http://altpwr.net/api.php?action=feedcontributions&feedformat=atom&user=PstchThe Alternative Power Network - User contributions [en]2026-07-15T09:56:48ZUser contributionsMediaWiki 1.32.2http://altpwr.net/index.php?title=Safety&diff=76Safety2019-08-22T12:05:51Z<p>Pstch: </p>
<hr />
<div>* '''NOTE:''' This document was not written by an electrical engineer, its author doesn't have enough knowledge and experience to be confident enough in its content. ''' ANYTHING DESIGNED USING THIS CONTENT SHOULD BE REVIEWED BEFORE ACTUAL USAGE'''. Please don't shock yourself.<br />
* '''TODO: Find someone to review and validate this content.'''<br />
<br />
As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
There are multiple earthing schemes that can be used for DC circuits.<br />
<br />
* '''TODO: Describe earthing schemes and their relation to micro-grids and their structure'''<br />
* '''TODO: Describe RCDs, their relation to the earthing scheme and implications of their use (problems with "normal" residual current leaks, for example with cheap power supplies).'''<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
The thermal breakers should always be sized so that they trip before the conductors overheat.<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
The magnetic breakers should aways be sized so that they can properly break the maximum fault current. For this, the different fault currents must be calculated (fault current for accidental mains connection, fault current for short-circuit anywhere in the circuit, etc).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
'''TODO: Describe how to handle these situations, add links to the existing circuit designs<br />
'''</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=75Safety2019-08-22T12:00:38Z<p>Pstch: </p>
<hr />
<div>'''NOTE:''' This document was not written by an electrical engineer, its author doesn't have enough knowledge and experience to be confident enough in its content. <br />
''' ANYTHING DESIGNED USING THIS CONTENT SHOULD BE REVIEWED BEFORE ACTUAL USAGE'''. <br />
Please don't shock yourself.<br />
<br />
'''TODO: Find someone to review and validate this content.'''<br />
<br />
As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
There are multiple earthing schemes that can be used for DC circuits.<br />
<br />
'''TODO: Describe earthing schemes and their relation to micro-grids and their structure'''<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
'''TODO: Describe how to handle these situations, add links to the existing circuit designs<br />
'''</div>Pstchhttp://altpwr.net/index.php?title=User_talk:Pstch&diff=74User talk:Pstch2019-08-22T11:58:52Z<p>Pstch: Created page with "Hi !"</p>
<hr />
<div>Hi !</div>Pstchhttp://altpwr.net/index.php?title=User:Pstch&diff=73User:Pstch2019-08-22T11:58:40Z<p>Pstch: </p>
<hr />
<div>* '''Name:''' Hugo Geoffroy<br />
* '''Handle:''' ''pstch'' or ''pistache''<br />
* '''E-mail:''' pistache@lebib.org<br />
* '''Languages:''' French/English/Greek<br />
* '''Experience in electrical engineering:''' Low<br />
* '''Experience in PV-systems:''' None<br />
<br />
Feel free to ask/tell me something in the [[User_talk:Pstch|talk page]].</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=72Safety2019-08-22T11:57:01Z<p>Pstch: </p>
<hr />
<div>'''NOTE:''' This document was not written by an electrical engineer, its author doesn't have enough knowledge and experience to be confident enough in its content. <br />
''' ANYTHING DESIGNED USING THIS CONTENT SHOULD BE REVIEWED BEFORE ACTUAL USAGE'''. <br />
Please don't shock yourself.<br />
<br />
'''TODO: Find someone to review and validate this content.'''<br />
<br />
As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
TODO: Describe how to handle these situations, add links to the existing circuit designs</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=71Safety2019-08-22T11:56:44Z<p>Pstch: </p>
<hr />
<div>'''NOTE:''' This document was not written by an electrical engineer, its author doesn't have enough knowledge and experience to be confident enough in its content. ''' <br />
ANYTHING DESIGNED USING THIS CONTENT SHOULD BE REVIEWED BEFORE ACTUAL USAGE'''. <br />
Please don't shock yourself.<br />
<br />
'''TODO: Find someone to review and validate this content.'''<br />
<br />
As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
TODO: Describe how to handle these situations, add links to the existing circuit designs</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=70Safety2019-08-22T11:56:31Z<p>Pstch: Formatting</p>
<hr />
<div>'''NOTE:''' This document was not written by an electrical engineer, its author doesn't have enough knowledge and experience to be confident enough in its content. ''' ANYTHING DESIGNED USING THIS CONTENT SHOULD BE REVIEWED BEFORE ACTUAL USAGE'''. Please don't shock yourself.<br />
<br />
'''TODO: Find someone to review and validate this content.'''<br />
<br />
As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
TODO: Describe how to handle these situations, add links to the existing circuit designs</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=69Safety2019-08-22T11:56:06Z<p>Pstch: </p>
<hr />
<div><big>'''NOTE:''' This document was not written by an electrical engineer, its author doesn't have enough knowledge and experience to be confident enough in its content. '''<br />
<br />
ANYTHING DESIGNED USING THIS CONTENT SHOULD BE REVIEWED BEFORE ACTUAL USAGE'''. Please don't shock yourself.</big><br />
<br />
'''TODO: Find someone to review and validate this content.'''<br />
<br />
As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
TODO: Describe how to handle these situations, add links to the existing circuit designs</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=68Safety2019-08-22T11:55:15Z<p>Pstch: </p>
<hr />
<div><big>'''NOTE:''' This document was not written by an electrical engineer, its author doesn't have enough knowledge and experience to be confident enough in its content. '''<br />
<br />
ANYTHING DESIGNED USING THIS CONTENT SHOULD BE REVIEWED BEFORE ACTUAL USAGE'''. Please don't shock yourself.</big><br />
<br />
As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
TODO: Describe how to handle these situations, add links to the existing circuit designs</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=67Safety2019-08-22T11:55:05Z<p>Pstch: Add warning</p>
<hr />
<div><big>'''NOTE:''' This document was not written by an electrical engineer, its author doesn't have enough knowledge and experience to be confident enough in its content. '''ANYTHING DESIGNED USING THIS CONTENT SHOULD BE REVIEWED BEFORE ACTUAL USAGE'''. Please don't shock yourself.</big><br />
<br />
As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
TODO: Describe how to handle these situations, add links to the existing circuit designs</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=66Safety2019-08-22T11:51:05Z<p>Pstch: </p>
<hr />
<div>As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over/under-voltage protection ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
TODO: Describe how to handle these situations, add links to the existing circuit designs</div>Pstchhttp://altpwr.net/index.php?title=Safety&diff=65Safety2019-08-22T11:50:25Z<p>Pstch: Create safety page</p>
<hr />
<div>As with all electrical systems, great care must be taken to keep the system safe and avoid injuries and equipment damage. Different systems are used for different hazards, and the characteristics of the electrical system (voltage, max current, user exposition) determines the required protections.<br />
<br />
== Isolation, earthing and residual currents ==<br />
<br />
Electrical circuits must be isolated from their environment, and conductors must be isolated from other conductors. Earthing (grounding) is used to keep the exposed condutive parts close to earth potential, so that we can avoid electrical shock and electrocutions. Earthing is also useful to protect against lightning strikes, and it can improve the behaviour of residual current detectors.<br />
<br />
Even in the case of very low-voltage circuits, there are multiple reasons why proper earthing can be required :<br />
* Voltage doesn't kill, but current does. In some conditions, even 12V will be able to pass through a body and stop a heart or even fry everything. <br />
* Voltage is not always guaranteed : over-voltage systems have their limits, and you may be on the wrong side of this system, in which case the over-voltage situations can get even worse as the circuit is opened.<br />
* It can help for the operation of some over-voltage protections (surge suppressors)<br />
<br />
== Over-current protection ==<br />
<br />
An over-current condition is defined as a conductor/equipment carrying more current than it has been designed for. This situation is handled by opening the circuit, usually after a delay (to allow start-up peaks), using a thermal breaker (that opens the circuit after it has heated up to a certain level).<br />
<br />
== Fault/short-circuit protection ==<br />
<br />
A current fault condition is defined as a conductor/equipment carrying "abnormal" current, where the current is "abnormal" in either/both its value or its rate of change. This situation can occur in the case of a "short-circuit", but also when the circuit is accidentally connected to a different circuit (for example, accidentally connecting a DC grid to the mains). This situation is handled by opening the circuit very quickly (because the fault current can be very high), using a magnetic breaker (that opens the circuit based on the rate of change of the current).<br />
<br />
== Over-voltage protection (also under-voltage) ==<br />
<br />
An over-voltage condition is defined as two conductors having a difference in potential that is out of the specified range. This situation can occur in the case of non-managed excess supply, or rapid unloading. It must be avoided because it can damage equipments, changes the operational characteristics of other safety devices, and decreases the resistance required to avoid carrying a current (increases the risk of an electrical shock). <br />
<br />
Under-voltage should ideally also be handled, as it can damage equipments and confuse an user/operator into thinking that a circuit is not connected to power. Under-voltage can occur in the case of lack of supply, or rapid loading.<br />
<br />
<br />
TODO: Describe how to handle these situations, add links to the existing circuit designs</div>Pstchhttp://altpwr.net/index.php?title=User:Pstch&diff=64User:Pstch2019-08-22T10:42:43Z<p>Pstch: Add personal info</p>
<hr />
<div>* '''Name:''' Hugo Geoffroy<br />
* '''Handle:''' ''pstch'' or ''pistache''<br />
* '''E-mail:''' pistache@lebib.org<br />
* '''Languages:''' French/English/Greek<br />
* '''Experience in electrical engineering:''' Low<br />
* '''Experience in PV-systems:''' None</div>Pstchhttp://altpwr.net/index.php?title=Grid_structure&diff=63Grid structure2019-08-22T10:39:47Z<p>Pstch: </p>
<hr />
<div>'''NOTE:''' ''This document is a draft, and it has been written by someone who may not have the required knowledge and experience in both PV-systems and electrical engineering. Feel free to correct mistakes, or to delete nonsensical content.''<br />
<br />
There are multiple ways to structure the micro-grid, some of which were mentioned in the D1 Micro-grid meet-up at CCCamp2019. These different structures depend on the scale of the grid (in terms of power, distance, and availability), but also on safety requirements and existing regulations, which determine what can be done practically.<br />
<br />
== Long-distance interconnections ==<br />
<br />
Very low voltage DC can not be carried very far, as the voltage drop implies a huge loss in efficiency. Multiple solutions were mentioned for this problem :<br />
<br />
* '''High(er) Voltage DC, around ~300V''' : tricky to work with (expensive equipment required), and not very safe (DC is hard to break, especially at such voltages), and requires a licensed electrician<br />
* '''Standard 230V AC''' : hard to synchronize properly, but already standardized. Sync problems can be avoided by only using unidirectional point-to-point links. The interconnection would present itself as a DC consumer to one side, and as a DC provider to the other. This way, standard, off-the-shelf equipment can be used.<br />
* '''"Sneaker-grid"''' : carrying batteries using mechanical/human power<br />
<br />
It may be useful to exchange data (supply, load, battery level, etc) between these subgrids. In that case, standard 230V AC would be practical, as it allows PLC using off-the-shelf equipment.<br />
<br />
== Short-distance interconnections ==<br />
<br />
Short-distance interconnections can be done directly using DC current. Because of this, it may be useful to use a standard voltage. 42V was used at SHA2017, but 48V is a good candidate too (multiple of 12, lower than 60V). Even with DC interconnection there are lots of variations possible :<br />
<br />
* The current flow can be bidirectional, or restricted to a single direction using diodes.<br />
* The connection can be passive, or active (opening the circuit when required, based on loads/supplies on each side of the connection)<br />
<br />
As these connections would not necessarily be point-to-point, it may be easier to conceptualize them as point-to-point links to a shared bus, which can be seen as battery. The diodes/switches would then be placed on the links to the shared bus. Designing and sizing this bus can be tricky (but very important) : ideally it needs to be able to carry the totality of the current supply, which could imply a big cable diameter. It may be possible to size the bus to less than the theoretical maximum current supply, but this would require some additional safety systems.<br />
<br />
It should also be noted that the fault current calculation is more complex when there are multiple power sources<br />
<br />
For active connections, it may be useful to exchange data between subgrids, for which a transmission method has to be determined. During the meeting, it was said that DC PLC is harder to do safely, as one would have to separate the signal from the relatively high DC currents.<br />
<br />
A quick look on the internet suggests that DC PLC is also possible. [https://www.tandfonline.com/doi/pdf/10.1080/22348972.2016.1217817 This paper] describes a DC PLC modem for PV cell monitoring.<br />
<br />
== PV-system interconnection ==<br />
<br />
The previous section covers short-distance subgrid interconnection, where each subgrid can be seen as a battery, but does not provide a solution for inter-grid PV-system interconnection (a concrete problem encountered by many at CCCamp 2019). Solutions to this problem were not discussed.<br />
<br />
* A possible solution could be to avoid using batteries for each PV controller, and instead use batteries on the shared bus. This also makes the system "simpler", as the shared bus is already mentally modeled as a battery. This would require a load/supply management circuit at the batteries. Note that "power availability" cannot be solely determined from the actual load : if some batteries are charging, there is "available power", but it would not be apparent in the bus voltage. Because of this, this load/supply management circuit would need to communicate an "available power" metric to the possible loads/users. Also, this load/supply management circuit would have to be able to control the generators (PV systems) in order to avoid excess supply when batteries are full, unless this excess supply can always be used by some Power-to-X load. It may be possible to use the bus voltage to communicate this situation to the generators, but the load/supply management circuit may be more efficient if it has a precise idea of the state of all generators (independently from the loads), which cannot be communicated by the shared bus voltage. The disadvantage of this solution is that it requires an additional battery charging circuit (+ the load/supply management system), because the existing PV-systems battery charging circuits can not be made to work with this shared bus.</div>Pstchhttp://altpwr.net/index.php?title=Grid_structure&diff=62Grid structure2019-08-22T10:37:36Z<p>Pstch: </p>
<hr />
<div>'''NOTE:''' ''This document is a draft, and it has been written by someone who may not have the required knowledge and experience in both PV-systems and electrical engineering. Feel free to correct mistakes, or to delete nonsensical content.''<br />
<br />
There are multiple ways to structure the micro-grid, some of which were mentioned in the D1 Micro-grid meet-up at CCCamp2019. These different structures depend on the scale of the grid (in terms of power, distance, and availability), but also on safety requirements and existing regulations, which determine what can be done practically.<br />
<br />
== Long-distance interconnections ==<br />
<br />
Very low voltage DC can not be carried very far, as the voltage drop implies a huge loss in efficiency. Multiple solutions were mentioned for this problem :<br />
<br />
* '''High(er) Voltage DC, around ~300V''' : tricky to work with (expensive equipment required), and not very safe (DC is hard to break, especially at such voltages), and requires a licensed electrician<br />
* '''Standard 230V AC''' : hard to synchronize properly, but already standardized. Sync problems can be avoided by only using unidirectional point-to-point links. The interconnection would present itself as a DC consumer to one side, and as a DC provider to the other. This way, standard, off-the-shelf equipment can be used.<br />
* '''"Sneaker-grid"''' : carrying batteries using mechanical/human power<br />
<br />
It may be useful to exchange data (supply, load, battery level, etc) between these subgrids. In that case, standard 230V AC would be practical, as it allows PLC using off-the-shelf equipment.<br />
<br />
== Short-distance interconnections ==<br />
<br />
Short-distance interconnections can be done directly using DC current. Because of this, it may be useful to use a standard voltage. 42V was used at SHA2017, but 48V is a good candidate too (multiple of 12, lower than 60V). Even with DC interconnection there are lots of variations possible :<br />
<br />
* The current flow can be bidirectional, or restricted to a single direction using diodes.<br />
* The connection can be passive, or active (opening the circuit when required, based on loads/supplies on each side of the connection)<br />
<br />
Then, there are two ways to interconnect the sub-grids :<br />
<br />
* Mesh-like structure : point-to-(multi)point links between the sub-grids<br />
* Shared bus structure : point-to-point links between each sub-grid and a shared bus<br />
<br />
Using this shared bus could help simplify the mental model and safety systems :<br />
<br />
* Fault current calculation in a mesh-like structure can be tricky, and so designing the safety systems could be much harder (and more expensive).<br />
* The shared bus can be viewed as battery (it can act as a load, or as a supply)<br />
* Breaker/fuses can be placed on the interconnection between the sub-grid and the bus<br />
* The bus would have to be sized to the maximum possible current flow between sub-grids (tricky to calculate), or have its own over-current protections.<br />
* It should be possible to bypass this shared bus (directly interconnect two sub-grids, if the proper safeties are set up). However, requiring that connections are made to the bus could help ensure that the system is properly safe, and would probably simplify the fault current calculations.<br />
* The problem with this approach is that '''the shared bus is a SPOF'''. A mesh-like structure could be much more resilient.<br />
<br />
For active connections, it may be useful to exchange data between sub-grids, for which a transmission method has to be determined. During the meeting, it was said that DC Power-Line is harder to do safely, as one would have to separate the signal from the relatively high DC currents.<br />
<br />
== PV-system interconnection ==<br />
<br />
The previous section covers short-distance subgrid interconnection, where each subgrid can be seen as a battery, but does not provide a solution for inter-grid PV-system interconnection (a concrete problem encountered by many at CCCamp 2019). Solutions to this problem were not discussed.<br />
<br />
* A possible solution could be to avoid using batteries for each PV controller, and instead use a battery bank on the shared bus. Again, this creates a SPOF. This also makes the system "simpler", as the shared bus is already mentally modeled as a battery. This would require a load/supply controller at the batteries. Note that "power availability" cannot be solely determined from the actual load : if some batteries are charging, there is "available power", but it would not be apparent in the bus voltage. Because of this, this load/supply management circuit would need to communicate an "available power" metric to the possible loads/users. Also, this load/supply controllers would have to be able to control the generators (PV systems) in order to avoid excess supply when batteries are full, unless this excess supply can always be used by some Power-to-X load. It may be possible to use the bus voltage to communicate this situation to the generators, but the load/supply controller may be more efficient if it has a precise idea of the state of all generators (independently from the loads), which cannot be communicated by the shared bus voltage. The disadvantage of this solution is that it requires an additional battery charging circuit (+ the load/supply management system), because the existing PV-systems battery charging circuits can probably not be made to work with this shared bus.<br />
<br />
* It should be possible to have multiple battery banks on the shared bus (eliminating the battery-bank-SPOF, but not the shared-bus-SPOF) if the load/supply circuits for each bank can properly cooperate. In that case, and if the load/supply controller communicates the excess supply situation to the PV-systems using the bus voltage, the voltage drop will have to be taken in account, and could even make this approach infeasible, requiring OOB communication between PV-systems and load/supply controllers.<br />
<br />
* It should also be possible to have multiple battery banks in a mesh-like structure (eliminating both SPOFs), but the load/supply controllers would have to be aware of the mesh structure and of its capacity (the definition of "available power" becomes much more complex, because it has to take in account the limitations of the path. in a shared bus structure, the "available power" is a byzantine problem (everyone has the same view of it), while in a mesh-like structure, "available power" has a different definition for each node of the mesh).</div>Pstchhttp://altpwr.net/index.php?title=Grid_structure&diff=61Grid structure2019-08-22T10:36:37Z<p>Pstch: </p>
<hr />
<div>'''NOTE:''' ''This document is a draft, and it has been written by someone who may not have the required knowledge and experience in both PV-systems and electrical engineering. Feel free to correct mistakes, or to delete nonsensical content.''<br />
<br />
There are multiple ways to structure the micro-grid, some of which were mentioned in the D1 Micro-grid meet-up at CCCamp2019. These different structures depend on the scale of the grid (in terms of power, distance, and availability), but also on safety requirements and existing regulations, which determine what can be done practically.<br />
<br />
== Long-distance interconnections ==<br />
<br />
Very low voltage DC can not be carried very far, as the voltage drop implies a huge loss in efficiency. Multiple solutions were mentioned for this problem :<br />
<br />
* '''High(er) Voltage DC, around ~300V''' : tricky to work with (expensive equipment required), and not very safe (DC is hard to break, especially at such voltages), and requires a licensed electrician<br />
* '''Standard 230V AC''' : hard to synchronize properly, but already standardized. Sync problems can be avoided by only using unidirectional point-to-point links. The interconnection would present itself as a DC consumer to one side, and as a DC provider to the other. This way, standard, off-the-shelf equipment can be used.<br />
* '''"Sneaker-grid"''' : carrying batteries using mechanical/human power<br />
<br />
It may be useful to exchange data (supply, load, battery level, etc) between these subgrids. In that case, standard 230V AC would be practical, as it allows PLC using off-the-shelf equipment.<br />
<br />
== Short-distance interconnections ==<br />
<br />
Short-distance interconnections can be done directly using DC current. Because of this, it may be useful to use a standard voltage. 42V was used at SHA2017, but 48V is a good candidate too (multiple of 12, lower than 60V). Even with DC interconnection there are lots of variations possible :<br />
<br />
* The current flow can be bidirectional, or restricted to a single direction using diodes.<br />
* The connection can be passive, or active (opening the circuit when required, based on loads/supplies on each side of the connection)<br />
<br />
Then, there are two ways to interconnect the sub-grids :<br />
<br />
* Mesh-like structure : point-to-(multi)point links between the sub-grids<br />
* Shared bus structure : point-to-point links between each sub-grid and a shared bus<br />
<br />
Using this shared bus could help simplify the mental model and safety systems :<br />
<br />
* Fault current calculation in a mesh-like structure can be tricky, and so designing the safety systems could be much harder (and more expensive).<br />
* The shared bus can be viewed as battery (it can act as a load, or as a supply)<br />
* Breaker/fuses can be placed on the interconnection between the sub-grid and the bus<br />
* The bus would have to be sized to the maximum possible current flow between sub-grids (tricky to calculate), or have its own over-current protections.<br />
* It should be possible to bypass this shared bus (directly interconnect two sub-grids, if the proper safeties are set up). However, requiring that connections are made to the bus could help ensure that the system is properly safe, and would probably simplify the fault current calculations.<br />
* The problem with this approach is that '''the shared bus is a SPOF'''. A mesh-like structure could be much more resilient.<br />
<br />
For active connections, it may be useful to exchange data between sub-grids, for which a transmission method has to be determined. During the meeting, it was said that DC Power-Line is harder to do safely, as one would have to separate the signal from the relatively high DC currents.<br />
<br />
== PV-system interconnection ==<br />
<br />
The previous section covers short-distance subgrid interconnection, where each subgrid can be seen as a battery, but does not provide a solution for inter-grid PV-system interconnection (a concrete problem encountered by many at CCCamp 2019). Solutions to this problem were not discussed.<br />
<br />
* A possible solution could be to avoid using batteries for each PV controller, and instead use a battery bank on the shared bus. Again, this creates a SPOF. This also makes the system "simpler", as the shared bus is already mentally modeled as a battery. This would require a load/supply controller at the batteries. Note that "power availability" cannot be solely determined from the actual load : if some batteries are charging, there is "available power", but it would not be apparent in the bus voltage. Because of this, this load/supply management circuit would need to communicate an "available power" metric to the possible loads/users. Also, this load/supply controllers would have to be able to control the generators (PV systems) in order to avoid excess supply when batteries are full, unless this excess supply can always be used by some Power-to-X load. It may be possible to use the bus voltage to communicate this situation to the generators, but the load/supply controller may be more efficient if it has a precise idea of the state of all generators (independently from the loads), which cannot be communicated by the shared bus voltage. The disadvantage of this solution is that it requires an additional battery charging circuit (+ the load/supply management system), because the existing PV-systems battery charging circuits can not be made to work with this shared bus.<br />
<br />
* It should be possible to have multiple battery banks on the shared bus (eliminating the battery-bank-SPOF, but not the shared-bus-SPOF) if the load/supply circuits for each bank can properly cooperate. In that case, and if the load/supply controller communicates the excess supply situation to the PV-systems using the bus voltage, the voltage drop will have to be taken in account, and could even make this approach infeasible, requiring OOB communication between PV-systems and load/supply controllers.<br />
<br />
* It should also be possible to have multiple battery banks in a mesh-like structure (eliminating both SPOFs), but the load/supply controllers would have to be aware of the mesh structure and of its capacity (the definition of "available power" becomes much more complex, because it has to take in account the limitations of the path. in a shared bus structure, the "available power" is a byzantine problem (everyone has the same view of it), while in a mesh-like structure, "available power" has a different definition for each node of the mesh).</div>Pstchhttp://altpwr.net/index.php?title=Camp2019_kits&diff=60Camp2019 kits2019-08-22T10:18:40Z<p>Pstch: Improve source code formatting</p>
<hr />
<div>'''At CCCamp 2019 there are a few electronic kits available for soldering, some related to our goal, some not.'''<br />
<br />
But anyway, here is the info you were looking for!<br />
<br />
=== Kit A: Solar powered noise maker: ===<br />
<br />
This kit is a simple bleeping sound generator, it has all SMD parts except for the headphone connector and the solar panel.<br />
<br />
[[File:PCB.png]]<br />
<br />
The PCB and components are RoHS compatible, but you could use leaded solder too. The small point on the outline of the LEDs is the anode/positive side of the LED. If you have finished soldering the PCB and there is a bit of light it should make some noise. Place your ear near the piezo or attach stereo headphones. The LEDs only blink in bright lights. The pads on the outside of the PCB can be used as finger contacts or to solder other components to influence the sound. The (-) pad on the top side of the picture is not connected correctly, but the other (-) pad is.<br />
<br />
[[File:Schema bliep.png]]<br />
<br />
=== Kit B: The EMF detector / RevSniffer: ===<br />
<br />
[[File:Revsniffer.png]]<br />
<br />
The schematic is pretty simple, but it works in a complex way. Any of the three transistors can work as an amplifier or detector. It all depends on the strength of the signal. <br />
After assembling, hold the button and point the inductor/antenna to the device you want to listen to. If there is a static or no field, you will hear some hissing noise, that's the noise generated by the electrons dancing inside the transistors. If there is a stable high frequency field, you will hear nothing, if there is some modulation, this will make all kinds of nice noises, from simple clicks to highly complex and beautiful sounds! Have fun! The provided headphones are cheap, so if you don't hear anything, try another set.<br />
<br />
=== Kit C: The AD(H)D timer ===<br />
<br />
This kit has a microcontroller that needs some programming, ask for benadski at the HSNL tent to get yours programmed after soldering. (Hopefully the toolchain is set up on Thursday evening.) <br />
<br />
;<br />
; ADDtimer.asm<br />
;<br />
; Created: 11/07/2019 21:43:20<br />
; Author : Wilenzo<br />
;<br />
; ___<br />
; VCC -|* |- GND<br />
; SW2 and TPI A0 -| |- B3 POT wiper<br />
; TPI A1 -| |- B2 POT V+ and buzzer<br />
; TPI /R -|___|- B1 SW1 and LEDs <br />
<br />
.def locl = r16<br />
.def stat = r17<br />
.def dly1 = r18<br />
.def dly2 = r19<br />
.def dlyi = r20<br />
.def loci = r21<br />
.def tmrd = r22<br />
<br />
;.def <br />
<br />
; Status byte <br />
.equ SLP = 0 ; Set before sleep is executed<br />
.equ ACP = 1 ; Analog conversion pending<br />
.equ SLR = 2 ; Sleep request<br />
.equ ALM = 3 ; Alarm (beeper and LEDs)<br />
<br />
; I/O pins or ADC channel<br />
.equ SW2 = 0<br />
.equ BTN = 1<br />
.equ LED = 1<br />
.equ BUZ = 2<br />
.equ POTP = 2<br />
.equ POTW = 7<br />
<br />
; Helpers<br />
.equ VLMON = (1<<VLM1)|(1<<VLM0)|(1<<VLMIE)<br />
<br />
; Init<br />
.org $0000<br />
rjmp RESET_vect<br />
<br />
.org $0001<br />
rjmp INT0_vect<br />
<br />
.org $0006<br />
rjmp TIM0_CA_vect<br />
<br />
.org $000A<br />
rjmp VLM_vect<br />
<br />
.org $000B<br />
rjmp ADC_vect<br />
<br />
;Handles button and wake function<br />
INT0_vect:<br />
; Wait for pin to get high, set pot positive high, wait a few msecs<br />
in loci, SREG<br />
push loci<br />
WAIT_PIN:<br />
sbis PINB, BTN<br />
rjmp WAIT_PIN<br />
<br />
sbr stat, (1<<ACP)<br />
sbi PORTB, POTP<br />
<br />
I0SNOOZE:<br />
dec dlyi<br />
brne I0SNOOZE<br />
<br />
; Check if awoken from sleep, if so: reset flag and ...<br />
sbrs stat, SLP<br />
rjmp NOSLEEP<br />
cbr stat, (1<<SLP)<br />
in locl, SMCR<br />
andi locl, ~(1<<SE)<br />
out SMCR, locl<br />
NOSLEEP:<br />
; Code for button processing, start A/D conversion<br />
sbi ADCSRA, ADSC<br />
<br />
INT0_end:<br />
pop loci<br />
out SREG, loci<br />
reti<br />
<br />
; Timing, fires every 30 seconds<br />
TIM0_CA_vect:<br />
in loci, SREG<br />
push loci <br />
<br />
;cpi tmrd, 0<br />
;breq REPEAT<br />
<br />
dec tmrd<br />
brne TIM0_END<br />
<br />
ldi tmrd, 255<br />
sbr stat, (1<<ALM)<br />
<br />
sbis PINA, SW2<br />
rjmp REPEAT<br />
rcall LED_OFF<br />
sbr stat, (1<<SLR)<br />
rjmp TIM0_END<br />
REPEAT:<br />
<br />
sbr stat, (1<<ACP)<br />
sbi PORTB, POTP<br />
<br />
T0SNOOZE:<br />
dec dlyi<br />
brne T0SNOOZE<br />
<br />
sbi ADCSRA, ADSC<br />
<br />
TIM0_END:<br />
pop loci<br />
out SREG, loci<br />
reti<br />
<br />
; Voltage level too low? Flash LED, do nothing else<br />
VLM_vect:<br />
in loci, SREG<br />
push loci <br />
<br />
sbi DDRB, LED<br />
<br />
ENDLESS:<br />
dec dlyi<br />
brne ENDLESS<br />
sbrc loci, 6<br />
rcall LED_ON<br />
dec loci<br />
brne ENDLESS<br />
ldi loci, 80<br />
rcall LED_OFF<br />
rjmp ENDLESS<br />
<br />
pop loci<br />
out SREG, loci<br />
reti<br />
<br />
; Conversion complete, set pot positive to 0V, process value<br />
ADC_vect:<br />
in loci, SREG<br />
push loci <br />
<br />
cbi PORTB, POTP<br />
cbr stat, (1<<ACP)<br />
in tmrd, ADCH<br />
lsr tmrd<br />
cpi tmrd, 10<br />
brsh MAX_VAL<br />
ldi tmrd, 10<br />
MAX_VAL:<br />
cpi tmrd, 120<br />
brlo VAL_OK<br />
ldi tmrd, 120<br />
VAL_OK:<br />
pop loci<br />
out SREG, loci<br />
reti<br />
<br />
; LED on (with safe pushbutton thing)<br />
LED_ON:<br />
ldi locl, 0<br />
out EIMSK, locl ; INT0 off<br />
nop<br />
nop<br />
cbi PORTB, LED<br />
sbi DDRB, LED<br />
ret<br />
<br />
; LED off (with safe pushbutton thing)<br />
LED_OFF:<br />
cbi DDRB, LED<br />
sbi PORTB, LED<br />
nop<br />
nop<br />
ldi locl, (1<<INT0)<br />
out EIMSK, locl ; INT0 (low level for waking from sleep)<br />
ret<br />
<br />
RESET_vect:<br />
cli<br />
<br />
clr stat<br />
ldi locl, low(RAMEND)<br />
out SPL, locl<br />
ldi locl, high(RAMEND)<br />
out SPH, locl<br />
<br />
; Set clock speed to 128kHz<br />
ldi locl, 0xD8<br />
out CCP, locl<br />
ldi locl, (1<<CLKMS0)<br />
out CLKMSR, locl<br />
ldi locl, 0xD8<br />
out CCP, locl<br />
clr locl<br />
out CLKPSR, locl<br />
<br />
; I/O init <br />
ldi locl, (1<<SW2)<br />
out PUEA, locl <br />
ldi locl, (1<<BUZ)<br />
out DDRB, locl<br />
ldi locl, (1<<BTN)<br />
out PUEB, locl<br />
<br />
FLASH:<br />
rcall LED_ON<br />
dec dly1<br />
brne FLASH<br />
rcall LED_OFF<br />
<br />
; ADC setup, point mux to pot wiper enable with interrupt, left adjust and turn off digital input<br />
ldi locl, POTW<br />
out ADMUX, locl<br />
ldi locl, (1<<ADEN)|(1<<ADIE)<br />
out ADCSRA, locl<br />
ldi locl, (1<<ADLAR)<br />
out ADCSRB, locl<br />
ldi locl, (1<<POTW)<br />
out DIDR0, locl<br />
<br />
; VLM setup (off for now)<br />
ldi locl, 0<br />
out VLMCSR, locl<br />
<br />
; Interrupts setup<br />
ldi locl, (1<<INT0)<br />
out EIMSK, locl ; INT0 (low level for waking from sleep)<br />
ldi locl, 0x60<br />
ldi loci, 0xEA<br />
out OCR0AH, loci ; Set timer compare match at 60000<br />
out OCR0AL, locl<br />
ldi locl, (1<<CS00)|(1<<CS01)|(1<<WGM02)<br />
out TCCR0B, locl ; CLKtmr = CLKio/64 => 2000Hz<br />
ldi locl, (1<<OCIE0A)<br />
out TIMSK0, locl ; Interrupt fires every 30 seconds.<br />
<br />
; Set sleep mode to power down<br />
ldi locl, (1<<SM1)<br />
out SMCR, locl ; (1<<SE) just before sleep instruction and clear after waking.<br />
<br />
; Enable interrupts and go<br />
sei<br />
rjmp MAIN<br />
<br />
ZZZ:<br />
cbr stat, (1<<SLR)<br />
sbr stat, (1<<SLP)<br />
in locl, SMCR<br />
ori locl, (1<<SE)<br />
out SMCR, locl<br />
sleep<br />
rjmp MAIN<br />
<br />
; Check if battery voltage is OK, delay is for settling time.<br />
VLM_CHECK:<br />
sbrc stat, ACP<br />
ret<br />
sbis PORTB, LED<br />
ret<br />
sbic PORTB, BUZ<br />
ret<br />
ldi locl, VLMON<br />
out VLMCSR, locl<br />
ldi dly1, 4 <br />
VLM_DLY:<br />
dec dly1<br />
brne VLM_DLY<br />
ldi locl, 0<br />
out VLMCSR, locl<br />
ret<br />
<br />
; LED and buzzer sequence<br />
ALARM:<br />
ldi dly2, 5<br />
ALARM_LOOP:<br />
;sbi PORTB, BUZ piezo only<br />
cbi PORTB, BUZ<br />
rcall LED_ON<br />
;cbi PORTB, BUZ piezo only<br />
dec dly1<br />
brne ALARM_LOOP<br />
rcall LED_OFF<br />
sbi PORTB, BUZ<br />
BLEEP:<br />
; sbi PORTB, BUZ piezo only<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
; cbi PORTB, BUZ piezo only<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
dec dly1<br />
brne BLEEP<br />
dec dly2<br />
brne ALARM_LOOP<br />
cbr stat, (1<<ALM)<br />
cbi PORTB, BUZ<br />
ret<br />
<br />
; Just wait here and check voltage from time to time<br />
MAIN:<br />
dec dly1<br />
brne MAIN<br />
sbrc stat, ALM<br />
rcall ALARM<br />
dec dly2<br />
brne MAIN<br />
rcall VLM_CHECK<br />
sbrc stat, SLR<br />
rjmp ZZZ<br />
rjmp MAIN<br />
<br />
[[File:Schema_ADHD.png]]<br />
<br />
=== Kit D: The Lithium cell balancer PCB ===<br />
<br />
This kit is an intelligent cell balancer prototype, the microcontroller can be programmed to read out the cell voltage, discharge the cell to a certain voltage and to send a undervoltage or overvoltage signal on a bus to another PCB that controls charging and discharging of the whole pack (or single cell).<br />
<br />
More info [[Lithium_batteries|here]]!</div>Pstchhttp://altpwr.net/index.php?title=Camp2019_kits&diff=59Camp2019 kits2019-08-22T10:17:26Z<p>Pstch: Improve source code formatting</p>
<hr />
<div>'''At CCCamp 2019 there are a few electronic kits available for soldering, some related to our goal, some not.'''<br />
<br />
But anyway, here is the info you were looking for!<br />
<br />
=== Kit A: Solar powered noise maker: ===<br />
<br />
This kit is a simple bleeping sound generator, it has all SMD parts except for the headphone connector and the solar panel.<br />
<br />
[[File:PCB.png]]<br />
<br />
The PCB and components are RoHS compatible, but you could use leaded solder too. The small point on the outline of the LEDs is the anode/positive side of the LED. If you have finished soldering the PCB and there is a bit of light it should make some noise. Place your ear near the piezo or attach stereo headphones. The LEDs only blink in bright lights. The pads on the outside of the PCB can be used as finger contacts or to solder other components to influence the sound. The (-) pad on the top side of the picture is not connected correctly, but the other (-) pad is.<br />
<br />
[[File:Schema bliep.png]]<br />
<br />
=== Kit B: The EMF detector / RevSniffer: ===<br />
<br />
[[File:Revsniffer.png]]<br />
<br />
The schematic is pretty simple, but it works in a complex way. Any of the three transistors can work as an amplifier or detector. It all depends on the strength of the signal. <br />
After assembling, hold the button and point the inductor/antenna to the device you want to listen to. If there is a static or no field, you will hear some hissing noise, that's the noise generated by the electrons dancing inside the transistors. If there is a stable high frequency field, you will hear nothing, if there is some modulation, this will make all kinds of nice noises, from simple clicks to highly complex and beautiful sounds! Have fun! The provided headphones are cheap, so if you don't hear anything, try another set.<br />
<br />
=== Kit C: The AD(H)D timer ===<br />
<br />
This kit has a microcontroller that needs some programming, ask for benadski at the HSNL tent to get yours programmed after soldering. (Hopefully the toolchain is set up on Thursday evening.) <br />
<br />
ExtraCrappyCode(tm); sorry for the mess, check the source of the page for a better view...<br />
<nowiki><br />
;<br />
; ADDtimer.asm<br />
;<br />
; Created: 11/07/2019 21:43:20<br />
; Author : Wilenzo<br />
;<br />
; ___<br />
; VCC -|* |- GND<br />
; SW2 and TPI A0 -| |- B3 POT wiper<br />
; TPI A1 -| |- B2 POT V+ and buzzer<br />
; TPI /R -|___|- B1 SW1 and LEDs <br />
<br />
.def locl = r16<br />
.def stat = r17<br />
.def dly1 = r18<br />
.def dly2 = r19<br />
.def dlyi = r20<br />
.def loci = r21<br />
.def tmrd = r22<br />
<br />
;.def <br />
<br />
; Status byte <br />
.equ SLP = 0 ; Set before sleep is executed<br />
.equ ACP = 1 ; Analog conversion pending<br />
.equ SLR = 2 ; Sleep request<br />
.equ ALM = 3 ; Alarm (beeper and LEDs)<br />
<br />
; I/O pins or ADC channel<br />
.equ SW2 = 0<br />
.equ BTN = 1<br />
.equ LED = 1<br />
.equ BUZ = 2<br />
.equ POTP = 2<br />
.equ POTW = 7<br />
<br />
; Helpers<br />
.equ VLMON = (1<<VLM1)|(1<<VLM0)|(1<<VLMIE)<br />
<br />
; Init<br />
.org $0000<br />
rjmp RESET_vect<br />
<br />
.org $0001<br />
rjmp INT0_vect<br />
<br />
.org $0006<br />
rjmp TIM0_CA_vect<br />
<br />
.org $000A<br />
rjmp VLM_vect<br />
<br />
.org $000B<br />
rjmp ADC_vect<br />
<br />
;Handles button and wake function<br />
INT0_vect:<br />
; Wait for pin to get high, set pot positive high, wait a few msecs<br />
in loci, SREG<br />
push loci<br />
WAIT_PIN:<br />
sbis PINB, BTN<br />
rjmp WAIT_PIN<br />
<br />
sbr stat, (1<<ACP)<br />
sbi PORTB, POTP<br />
<br />
I0SNOOZE:<br />
dec dlyi<br />
brne I0SNOOZE<br />
<br />
; Check if awoken from sleep, if so: reset flag and ...<br />
sbrs stat, SLP<br />
rjmp NOSLEEP<br />
cbr stat, (1<<SLP)<br />
in locl, SMCR<br />
andi locl, ~(1<<SE)<br />
out SMCR, locl<br />
NOSLEEP:<br />
; Code for button processing, start A/D conversion<br />
sbi ADCSRA, ADSC<br />
<br />
INT0_end:<br />
pop loci<br />
out SREG, loci<br />
reti<br />
<br />
; Timing, fires every 30 seconds<br />
TIM0_CA_vect:<br />
in loci, SREG<br />
push loci <br />
<br />
;cpi tmrd, 0<br />
;breq REPEAT<br />
<br />
dec tmrd<br />
brne TIM0_END<br />
<br />
ldi tmrd, 255<br />
sbr stat, (1<<ALM)<br />
<br />
sbis PINA, SW2<br />
rjmp REPEAT<br />
rcall LED_OFF<br />
sbr stat, (1<<SLR)<br />
rjmp TIM0_END<br />
REPEAT:<br />
<br />
sbr stat, (1<<ACP)<br />
sbi PORTB, POTP<br />
<br />
T0SNOOZE:<br />
dec dlyi<br />
brne T0SNOOZE<br />
<br />
sbi ADCSRA, ADSC<br />
<br />
TIM0_END:<br />
pop loci<br />
out SREG, loci<br />
reti<br />
<br />
; Voltage level too low? Flash LED, do nothing else<br />
VLM_vect:<br />
in loci, SREG<br />
push loci <br />
<br />
sbi DDRB, LED<br />
<br />
ENDLESS:<br />
dec dlyi<br />
brne ENDLESS<br />
sbrc loci, 6<br />
rcall LED_ON<br />
dec loci<br />
brne ENDLESS<br />
ldi loci, 80<br />
rcall LED_OFF<br />
rjmp ENDLESS<br />
<br />
pop loci<br />
out SREG, loci<br />
reti<br />
<br />
; Conversion complete, set pot positive to 0V, process value<br />
ADC_vect:<br />
in loci, SREG<br />
push loci <br />
<br />
cbi PORTB, POTP<br />
cbr stat, (1<<ACP)<br />
in tmrd, ADCH<br />
lsr tmrd<br />
cpi tmrd, 10<br />
brsh MAX_VAL<br />
ldi tmrd, 10<br />
MAX_VAL:<br />
cpi tmrd, 120<br />
brlo VAL_OK<br />
ldi tmrd, 120<br />
VAL_OK:<br />
pop loci<br />
out SREG, loci<br />
reti<br />
<br />
; LED on (with safe pushbutton thing)<br />
LED_ON:<br />
ldi locl, 0<br />
out EIMSK, locl ; INT0 off<br />
nop<br />
nop<br />
cbi PORTB, LED<br />
sbi DDRB, LED<br />
ret<br />
<br />
; LED off (with safe pushbutton thing)<br />
LED_OFF:<br />
cbi DDRB, LED<br />
sbi PORTB, LED<br />
nop<br />
nop<br />
ldi locl, (1<<INT0)<br />
out EIMSK, locl ; INT0 (low level for waking from sleep)<br />
ret<br />
<br />
RESET_vect:<br />
cli<br />
<br />
clr stat<br />
ldi locl, low(RAMEND)<br />
out SPL, locl<br />
ldi locl, high(RAMEND)<br />
out SPH, locl<br />
<br />
; Set clock speed to 128kHz<br />
ldi locl, 0xD8<br />
out CCP, locl<br />
ldi locl, (1<<CLKMS0)<br />
out CLKMSR, locl<br />
ldi locl, 0xD8<br />
out CCP, locl<br />
clr locl<br />
out CLKPSR, locl<br />
<br />
; I/O init <br />
ldi locl, (1<<SW2)<br />
out PUEA, locl <br />
ldi locl, (1<<BUZ)<br />
out DDRB, locl<br />
ldi locl, (1<<BTN)<br />
out PUEB, locl<br />
<br />
FLASH:<br />
rcall LED_ON<br />
dec dly1<br />
brne FLASH<br />
rcall LED_OFF<br />
<br />
; ADC setup, point mux to pot wiper enable with interrupt, left adjust and turn off digital input<br />
ldi locl, POTW<br />
out ADMUX, locl<br />
ldi locl, (1<<ADEN)|(1<<ADIE)<br />
out ADCSRA, locl<br />
ldi locl, (1<<ADLAR)<br />
out ADCSRB, locl<br />
ldi locl, (1<<POTW)<br />
out DIDR0, locl<br />
<br />
; VLM setup (off for now)<br />
ldi locl, 0<br />
out VLMCSR, locl<br />
<br />
; Interrupts setup<br />
ldi locl, (1<<INT0)<br />
out EIMSK, locl ; INT0 (low level for waking from sleep)<br />
ldi locl, 0x60<br />
ldi loci, 0xEA<br />
out OCR0AH, loci ; Set timer compare match at 60000<br />
out OCR0AL, locl<br />
ldi locl, (1<<CS00)|(1<<CS01)|(1<<WGM02)<br />
out TCCR0B, locl ; CLKtmr = CLKio/64 => 2000Hz<br />
ldi locl, (1<<OCIE0A)<br />
out TIMSK0, locl ; Interrupt fires every 30 seconds.<br />
<br />
; Set sleep mode to power down<br />
ldi locl, (1<<SM1)<br />
out SMCR, locl ; (1<<SE) just before sleep instruction and clear after waking.<br />
<br />
; Enable interrupts and go<br />
sei<br />
rjmp MAIN<br />
<br />
ZZZ:<br />
cbr stat, (1<<SLR)<br />
sbr stat, (1<<SLP)<br />
in locl, SMCR<br />
ori locl, (1<<SE)<br />
out SMCR, locl<br />
sleep<br />
rjmp MAIN<br />
<br />
; Check if battery voltage is OK, delay is for settling time.<br />
VLM_CHECK:<br />
sbrc stat, ACP<br />
ret<br />
sbis PORTB, LED<br />
ret<br />
sbic PORTB, BUZ<br />
ret<br />
ldi locl, VLMON<br />
out VLMCSR, locl<br />
ldi dly1, 4 <br />
VLM_DLY:<br />
dec dly1<br />
brne VLM_DLY<br />
ldi locl, 0<br />
out VLMCSR, locl<br />
ret<br />
<br />
; LED and buzzer sequence<br />
ALARM:<br />
ldi dly2, 5<br />
ALARM_LOOP:<br />
;sbi PORTB, BUZ piezo only<br />
cbi PORTB, BUZ<br />
rcall LED_ON<br />
;cbi PORTB, BUZ piezo only<br />
dec dly1<br />
brne ALARM_LOOP<br />
rcall LED_OFF<br />
sbi PORTB, BUZ<br />
BLEEP:<br />
; sbi PORTB, BUZ piezo only<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
; cbi PORTB, BUZ piezo only<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
nop<br />
dec dly1<br />
brne BLEEP<br />
dec dly2<br />
brne ALARM_LOOP<br />
cbr stat, (1<<ALM)<br />
cbi PORTB, BUZ<br />
ret<br />
<br />
; Just wait here and check voltage from time to time<br />
MAIN:<br />
dec dly1<br />
brne MAIN<br />
sbrc stat, ALM<br />
rcall ALARM<br />
dec dly2<br />
brne MAIN<br />
rcall VLM_CHECK<br />
sbrc stat, SLR<br />
rjmp ZZZ<br />
rjmp MAIN<br />
</nowiki><br />
<br />
[[File:Schema_ADHD.png]]<br />
<br />
=== Kit D: The Lithium cell balancer PCB ===<br />
<br />
This kit is an intelligent cell balancer prototype, the microcontroller can be programmed to read out the cell voltage, discharge the cell to a certain voltage and to send a undervoltage or overvoltage signal on a bus to another PCB that controls charging and discharging of the whole pack (or single cell).<br />
<br />
More info [[Lithium_batteries|here]]!</div>Pstchhttp://altpwr.net/index.php?title=Links&diff=58Links2019-08-22T10:14:26Z<p>Pstch: </p>
<hr />
<div>This page contains useful links related to micro-grid design and operation :<br />
<br />
== Background info ==<br />
<br />
* [https://en.wikipedia.org/wiki/Microgrid#Advantages WP: Microgrid]<br />
* [https://en.wikipedia.org/wiki/Maximum_power_point_tracker WP: Maximum power-point tracker]<br />
* [https://en.wikipedia.org/wiki/Distributed_generation WP: Distributed generation]<br />
<br />
== Existing projects ==<br />
<br />
* [https://www.cet.or.at/pdf_files/Paspberry%20Pi%20Microgrid%20Controller.pdf A flexible low cost PV/EV microgrid controller concept based on a Raspberry Pi]<br />
* [https://www.tandfonline.com/doi/pdf/10.1080/22348972.2016.1217817 DC PLC modem for PV cell monitoring]</div>Pstchhttp://altpwr.net/index.php?title=Grid_structure&diff=57Grid structure2019-08-22T09:54:11Z<p>Pstch: </p>
<hr />
<div>'''NOTE:''' ''This document is a draft, and it has been written by someone who may not have the required knowledge and experience in both PV-systems and electrical engineering. Feel free to correct mistakes, or to delete nonsensical content.''<br />
<br />
There are multiple ways to structure the micro-grid, some of which were mentioned in the D1 Micro-grid meet-up at CCCamp2019. These different structures depend on the scale of the grid (in terms of power, distance, and availability), but also on safety requirements and existing regulations, which determine what can be done practically.<br />
<br />
== Long-distance interconnections ==<br />
<br />
Very low voltage DC can not be carried very far, as the voltage drop implies a huge loss in efficiency. Multiple solutions were mentioned for this problem :<br />
<br />
* '''High(er) Voltage DC, around ~300V''' : tricky to work with (expensive equipment required), and not very safe (DC is hard to break, especially at such voltages), and requires a licensed electrician<br />
* '''Standard 230V AC''' : hard to synchronize properly, but already standardized. Sync problems can be avoided by only using unidirectional point-to-point links. The interconnection would present itself as a DC consumer to one side, and as a DC provider to the other. This way, standard, off-the-shelf equipment can be used.<br />
* '''"Sneaker-grid"''' : carrying batteries using mechanical/human power<br />
<br />
It may be useful to exchange data (supply, load, battery level, etc) between these subgrids. In that case, standard 230V AC would be practical, as it allows PLC using off-the-shelf equipment.<br />
<br />
== Short-distance interconnections ==<br />
<br />
Short-distance interconnections can be done directly using DC current. Because of this, it may be useful to use a standard voltage. 42V was used at SHA2017, but 48V is a good candidate too (multiple of 12, lower than 60V). Even with DC interconnection there are lots of variations possible :<br />
<br />
- The current flow can be bidirectional, or restricted to a single direction using diodes.<br />
- The connection can be passive, or active (opening the circuit when required, based on loads/supplies on each side of the connection)<br />
<br />
As these connections would not necessarily be point-to-point, it may be easier to conceptualize them as point-to-point links to a shared bus, which can be seen as battery. The diodes/switches would then be placed on the links to the shared bus. Designing and sizing this bus can be tricky (but very important) : ideally it needs to be able to carry the totality of the current supply, which could imply a big cable diameter. It may be possible to size the bus to less than the theoretical maximum current supply, but this would require some additional safety systems.<br />
<br />
It should also be noted that the fault current calculation is more complex when there are multiple power sources<br />
<br />
For active connections, it may be useful to exchange data between subgrids, for which a transmission method has to be determined. During the meeting, it was said that DC PLC is harder to do safely, as one would have to separate the signal from the relatively high DC currents.<br />
<br />
A quick look on the internet suggests that DC PLC is also possible. [https://www.tandfonline.com/doi/pdf/10.1080/22348972.2016.1217817 This paper] describes a DC PLC modem for PV cell monitoring.<br />
<br />
== PV-system interconnection ==<br />
<br />
The previous section covers short-distance subgrid interconnection, where each subgrid can be seen as a battery, but does not provide a solution for inter-grid PV-system interconnection (a concrete problem encountered by many at CCCamp 2019). Solutions to this problem were not discussed.<br />
<br />
* A possible solution could be to avoid using batteries for each PV controller, and instead use batteries on the shared bus. This also makes the system "simpler", as the shared bus is already mentally modeled as a battery. This would require a load/supply management circuit at the batteries. Note that "power availability" cannot be solely determined from the actual load : if some batteries are charging, there is "available power", but it would not be apparent in the bus voltage. Because of this, this load/supply management circuit would need to communicate an "available power" metric to the possible loads/users. Also, this load/supply management circuit would have to be able to control the generators (PV systems) in order to avoid excess supply when batteries are full, unless this excess supply can always be used by some Power-to-X load. It may be possible to use the bus voltage to communicate this situation to the generators, but the load/supply management circuit may be more efficient if it has a precise idea of the state of all generators (independently from the loads), which cannot be communicated by the shared bus voltage. The disadvantage of this solution is that it requires an additional battery charging circuit (+ the load/supply management system), because the existing PV-systems battery charging circuits can not be made to work with this shared bus.</div>Pstchhttp://altpwr.net/index.php?title=Grid_structure&diff=56Grid structure2019-08-22T09:53:52Z<p>Pstch: Add headings</p>
<hr />
<div>'''NOTE:''' ''This document is a draft, and it has been written by someone who may not have the required knowledge and experience in both PV-systems and electrical engineering. Feel free to correct mistakes, or to delete nonsensical content.''<br />
<br />
There are multiple ways to structure the micro-grid, some of which were mentioned in the D1 Micro-grid meet-up at CCCamp2019. These different structures depend on the scale of the grid (in terms of power, distance, and availability), but also on safety requirements and existing regulations, which determine what can be done practically.<br />
<br />
== Long-distance interconnections ==<br />
<br />
Very low voltage DC can not be carried very far, as the voltage drop implies a huge loss in efficiency. Multiple solutions were mentioned for this problem :<br />
<br />
* '''High(er) Voltage DC, around ~300V''' : tricky to work with (expensive equipment required), and not very safe (DC is hard to break, especially at such voltages), and requires a licensed electrician<br />
* '''Standard 230V AC''' : hard to synchronize properly, but already standardized. Sync problems can be avoided by only using unidirectional point-to-point links. The interconnection would present itself as a DC consumer to one side, and as a DC provider to the other. This way, standard, off-the-shelf equipment can be used.<br />
* '''"Sneaker-grid"''' : carrying batteries using mechanical/human power<br />
<br />
It may be useful to exchange data (supply, load, battery level, etc) between these subgrids. In that case, standard 230V AC would be practical, as it allows PLC using off-the-shelf equipment.<br />
<br />
== Short-distance interconnections ==<br />
<br />
Short-distance interconnections can be done directly using DC current. Because of this, it may be useful to use a standard voltage. 42V was used at SHA2017, but 48V is a good candidate too (multiple of 12, lower than 60V). Even with DC interconnection there are lots of variations possible :<br />
<br />
- The current flow can be bidirectional, or restricted to a single direction using diodes.<br />
- The connection can be passive, or active (opening the circuit when required, based on loads/supplies on each side of the connection)<br />
<br />
As these connections would not necessarily be point-to-point, it may be easier to conceptualize them as point-to-point links to a shared bus, which can be seen as battery. The diodes/switches would then be placed on the links to the shared bus. Designing and sizing this bus can be tricky (but very important) : ideally it needs to be able to carry the totality of the current supply, which could imply a big cable diameter. It may be possible to size the bus to less than the theoretical maximum current supply, but this would require some additional safety systems.<br />
<br />
It should also be noted that the fault current calculation is more complex when there are multiple power sources<br />
<br />
For active connections, it may be useful to exchange data between subgrids, for which a transmission method has to be determined. During the meeting, it was said that DC PLC is harder to do safely, as one would have to separate the signal from the relatively high DC currents.<br />
<br />
A quick look on the internet suggests that DC PLC is also possible. [https://www.tandfonline.com/doi/pdf/10.1080/22348972.2016.1217817 This paper] describes a DC PLC modem for PV cell monitoring.<br />
<br />
== PV-system interconnection ==<br />
<br />
The previous section covers short-distance subgrid interconnection, where each subgrid can be seen as a battery, but does not provide a solution for inter-grid PV-system interconnection (a concrete problem encountered by many at CCCamp 2019). Solutions to this problem were not discussed.<br />
<br />
* A possible solution could be to avoid using batteries for each PV controller, and instead use batteries on the shared bus. This also makes the system "simpler", as the shared bus is already mentally modeled as a battery. This would require a load/supply management circuit at the batteries. Note that "power availability" cannot be solely determined from the actual load : if some batteries are charging, there is "available power", but it would not be apparent in the bus voltage. Because of this, this load/supply management circuit would need to communicate an "available power" metric to the possible loads/users. Also, this load/supply management circuit would have to be able to control the generators (PV systems) in order to avoid excess supply when batteries are full, unless this excess supply can always be used by some Power-to-X load. It may be possible to use the bus voltage to communicate this situation to the generators, but the load/supply management circuit may be more efficient if it has a precise idea of the state of all generators (independently from the loads), which cannot be communicated by the shared bus voltage. The disadvantage of this solution is that it requires an additional battery charging circuit (+ the load/supply management system), because the existing PV-systems battery charging circuits can not be made to work with this shared bus.</div>Pstchhttp://altpwr.net/index.php?title=Grid_structure&diff=55Grid structure2019-08-22T09:53:11Z<p>Pstch: Formatting fixes</p>
<hr />
<div>'''NOTE:''' ''This document is a draft, and it has been written by someone who may not have the required knowledge and experience in both PV-systems and electrical engineering. Feel free to correct mistakes, or to delete nonsensical content.''<br />
<br />
There are multiple ways to structure the micro-grid, some of which were mentioned in the D1 Micro-grid meet-up at CCCamp2019. These different structures depend on the scale of the grid (in terms of power, distance, and availability), but also on safety requirements and existing regulations, which determine what can be done practically.<br />
<br />
1. Long-distance interconnections<br />
<br />
Very low voltage DC can not be carried very far, as the voltage drop implies a huge loss in efficiency. Multiple solutions were mentioned for this problem :<br />
<br />
* '''High(er) Voltage DC, around ~300V''' : tricky to work with (expensive equipment required), and not very safe (DC is hard to break, especially at such voltages), and requires a licensed electrician<br />
* '''Standard 230V AC''' : hard to synchronize properly, but already standardized. Sync problems can be avoided by only using unidirectional point-to-point links. The interconnection would present itself as a DC consumer to one side, and as a DC provider to the other. This way, standard, off-the-shelf equipment can be used.<br />
* '''"Sneaker-grid"''' : carrying batteries using mechanical/human power<br />
<br />
It may be useful to exchange data (supply, load, battery level, etc) between these subgrids. In that case, standard 230V AC would be practical, as it allows PLC using off-the-shelf equipment.<br />
<br />
2. Short-distance interconnections<br />
<br />
Short-distance interconnections can be done directly using DC current. Because of this, it may be useful to use a standard voltage. 42V was used at SHA2017, but 48V is a good candidate too (multiple of 12, lower than 60V). Even with DC interconnection there are lots of variations possible :<br />
<br />
- The current flow can be bidirectional, or restricted to a single direction using diodes.<br />
- The connection can be passive, or active (opening the circuit when required, based on loads/supplies on each side of the connection)<br />
<br />
As these connections would not necessarily be point-to-point, it may be easier to conceptualize them as point-to-point links to a shared bus, which can be seen as battery. The diodes/switches would then be placed on the links to the shared bus. Designing and sizing this bus can be tricky (but very important) : ideally it needs to be able to carry the totality of the current supply, which could imply a big cable diameter. It may be possible to size the bus to less than the theoretical maximum current supply, but this would require some additional safety systems.<br />
<br />
It should also be noted that the fault current calculation is more complex when there are multiple power sources<br />
<br />
For active connections, it may be useful to exchange data between subgrids, for which a transmission method has to be determined. During the meeting, it was said that DC PLC is harder to do safely, as one would have to separate the signal from the relatively high DC currents.<br />
<br />
A quick look on the internet suggests that DC PLC is also possible. [https://www.tandfonline.com/doi/pdf/10.1080/22348972.2016.1217817 This paper] describes a DC PLC modem for PV cell monitoring.<br />
<br />
3. PV-system interconnection<br />
<br />
The previous section covers short-distance subgrid interconnection, where each subgrid can be seen as a battery, but does not provide a solution for inter-grid PV-system interconnection (a concrete problem encountered by many at CCCamp 2019). Solutions to this problem were not discussed.<br />
<br />
* A possible solution could be to avoid using batteries for each PV controller, and instead use batteries on the shared bus. This also makes the system "simpler", as the shared bus is already mentally modeled as a battery. This would require a load/supply management circuit at the batteries. Note that "power availability" cannot be solely determined from the actual load : if some batteries are charging, there is "available power", but it would not be apparent in the bus voltage. Because of this, this load/supply management circuit would need to communicate an "available power" metric to the possible loads/users. Also, this load/supply management circuit would have to be able to control the generators (PV systems) in order to avoid excess supply when batteries are full, unless this excess supply can always be used by some Power-to-X load. It may be possible to use the bus voltage to communicate this situation to the generators, but the load/supply management circuit may be more efficient if it has a precise idea of the state of all generators (independently from the loads), which cannot be communicated by the shared bus voltage. The disadvantage of this solution is that it requires an additional battery charging circuit (+ the load/supply management system), because the existing PV-systems battery charging circuits can not be made to work with this shared bus.</div>Pstchhttp://altpwr.net/index.php?title=Grid_structure&diff=54Grid structure2019-08-22T09:52:24Z<p>Pstch: Created page with "'''NOTE:''' ''This document is a draft, and it has been written by someone who may not have the required knowledge and experience in both PV-systems and electrical engineering..."</p>
<hr />
<div>'''NOTE:''' ''This document is a draft, and it has been written by someone who may not have the required knowledge and experience in both PV-systems and electrical engineering. Feel free to correct mistakes, or to delete nonsensical content.''<br />
<br />
There are multiple ways to structure the micro-grid, some of which were mentioned in the D1 Micro-grid meet-up at CCCamp2019. These different structures depend on the scale of the grid (in terms of power, distance, and availability), but also on safety requirements and existing regulations, which determine what can be done practically.<br />
<br />
1. Long-distance interconnections<br />
<br />
Very low voltage DC can not be carried very far, as the voltage drop implies a huge loss in efficiency. Multiple solutions were mentioned for this problem :<br />
<br />
- High(er) Voltage DC, around ~300V : tricky to work with (expensive equipment required), and not very safe (DC is hard to break, especially at such voltages), and requires a licensed electrician<br />
- Standard 230V AC : hard to synchronize properly, but already standardized. Sync problems can be avoided by only using unidirectional point-to-point links. The interconnection would present itself as a DC consumer to one side, and as a DC provider to the other. This way, standard, off-the-shelf equipment can be used.<br />
- "Sneaker-grid" : carrying batteries using mechanical/human power<br />
<br />
It may be useful to exchange data (supply, load, battery level, etc) between these subgrids. In that case, standard 230V AC would be practical, as it allows PLC using off-the-shelf equipment.<br />
<br />
2. Short-distance interconnections<br />
<br />
Short-distance interconnections can be done directly using DC current. Because of this, it may be useful to use a standard voltage. 42V was used at SHA2017, but 48V is a good candidate too (multiple of 12, lower than 60V). Even with DC interconnection there are lots of variations possible :<br />
<br />
- The current flow can be bidirectional, or restricted to a single direction using diodes.<br />
- The connection can be passive, or active (opening the circuit when required, based on loads/supplies on each side of the connection)<br />
<br />
As these connections would not necessarily be point-to-point, it may be easier to conceptualize them as point-to-point links to a shared bus, which can be seen as battery. The diodes/switches would then be placed on the links to the shared bus. Designing and sizing this bus can be tricky (but very important) : ideally it needs to be able to carry the totality of the current supply, which could imply a big cable diameter. It may be possible to size the bus to less than the theoretical maximum current supply, but this would require some additional safety systems.<br />
<br />
It should also be noted that the fault current calculation is more complex when there are multiple power sources<br />
<br />
For active connections, it may be useful to exchange data between subgrids, for which a transmission method has to be determined. During the meeting, it was said that DC PLC is harder to do safely, as one would have to separate the signal from the relatively high DC currents.<br />
<br />
A quick look on the internet suggests that DC PLC is also possible. [This paper](https://www.tandfonline.com/doi/pdf/10.1080/22348972.2016.1217817) describes a DC PLC modem for PV cell monitoring.<br />
<br />
3. PV-system interconnection<br />
<br />
The previous section covers short-distance subgrid interconnection, where each subgrid can be seen as a battery, but does not provide a solution for inter-grid PV-system interconnection (a concrete problem encountered by many at CCCamp 2019). Solutions to this problem were not discussed.<br />
<br />
* A possible solution could be to avoid using batteries for each PV controller, and instead use batteries on the shared bus. This also makes the system "simpler", as the shared bus is already mentally modeled as a battery. This would require a load/supply management circuit at the batteries. Note that "power availability" cannot be solely determined from the actual load : if some batteries are charging, there is "available power", but it would not be apparent in the bus voltage. Because of this, this load/supply management circuit would need to communicate an "available power" metric to the possible loads/users. Also, this load/supply management circuit would have to be able to control the generators (PV systems) in order to avoid excess supply when batteries are full, unless this excess supply can always be used by some Power-to-X load. It may be possible to use the bus voltage to communicate this situation to the generators, but the load/supply management circuit may be more efficient if it has a precise idea of the state of all generators (independently from the loads), which cannot be communicated by the shared bus voltage. The disadvantage of this solution is that it requires an additional battery charging circuit (+ the load/supply management system), because the existing PV-systems battery charging circuits can not be made to work with this shared bus.</div>Pstchhttp://altpwr.net/index.php?title=Links&diff=53Links2019-08-22T08:29:05Z<p>Pstch: </p>
<hr />
<div>This page contains useful links related to micro-grid design and operation :<br />
<br />
== Background info ==<br />
<br />
* [https://en.wikipedia.org/wiki/Microgrid#Advantages WP: Microgrid]<br />
* [https://fr.wikipedia.org/wiki/Maximum_power_point_tracker WP: Maximum power-point tracker]<br />
* [https://en.wikipedia.org/wiki/Distributed_generation WP: Distributed generation]<br />
<br />
== Existing projects ==<br />
<br />
* [https://www.cet.or.at/pdf_files/Paspberry%20Pi%20Microgrid%20Controller.pdf A flexible low cost PV/EV microgrid controller concept based on a Raspberry Pi]</div>Pstchhttp://altpwr.net/index.php?title=Links&diff=52Links2019-08-22T08:28:25Z<p>Pstch: </p>
<hr />
<div>This page contains useful links related to micro-grid design and operation :<br />
<br />
== Background info ==<br />
<br />
[http://foo Wikipedia : Microgrid]<br />
- [https://en.wikipedia.org/wiki/Microgrid#Advantages WP: Microgrid]<br />
- [https://fr.wikipedia.org/wiki/Maximum_power_point_tracker WP: Maximum power-point tracker]<br />
- [https://en.wikipedia.org/wiki/Distributed_generation WP: Distributed generation]<br />
<br />
== Existing projects ==<br />
<br />
- [https://www.cet.or.at/pdf_files/Paspberry%20Pi%20Microgrid%20Controller.pdf A flexible low cost PV/EV microgrid controller concept based on a Raspberry Pi]</div>Pstchhttp://altpwr.net/index.php?title=Links&diff=51Links2019-08-22T08:26:51Z<p>Pstch: Add some initial links</p>
<hr />
<div>This page contains useful links related to micro-grid design and operation :<br />
<br />
== Background info ==<br />
<br />
- [Wikipedia : Microgrid](https://en.wikipedia.org/wiki/Microgrid#Advantages)<br />
- [Wikipedia : Maximum power-point tracker](https://fr.wikipedia.org/wiki/Maximum_power_point_tracker)<br />
- [Wikipedia : Distributed Gneration](https://en.wikipedia.org/wiki/Distributed_generation)<br />
<br />
== Existing projects ==<br />
<br />
- [A flexible low cost PV/EV microgrid controller concept based on a Raspberry P](https://www.cet.or.at/pdf_files/Paspberry%20Pi%20Microgrid%20Controller.pdf)</div>Pstch