INTELLIGENT SAFETY DISCONNECT SWITCHING

• US 20140265638A1
• Filed: 03/15/2013
• Published: 09/18/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Solantro Semiconductor Corp. (China Electronics Corporation)
• Original Assignee: Solantro Semiconductor Corp. (China Electronics Corporation)
• Inventors: Orr, Raymond Kenneth, Keyes, Edward, Paquin, Antoine Marc Joseph Richard
• Granted Patent: US 9,524,832 B2
• Time in Patent Office: Days
• US Class Current: 307/131
• CPC Class Codes: H01H 9/00 Details of switching devices, not covered by groups H01H1/00 - H01H7/00
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/40 Synchronising a generator for connection to a network or to another generator
• CPC Class Codes: H02S 40/36 characterised by special electrical interconnection means between two or more PV modules, e.g. electrical module-to-module connection
• CPC Class Codes: H02S 50/00 Monitoring or testing of PV systems, e.g. load balancing or fault identification
• CPC Class Codes: H02S 50/10 Testing of PV devices, e.g. of PV modules or single PV cells testing of semiconductor devices during manufacturing H01L22/00
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

Intelligent safety disconnect switching methods and arrangements for PhotoVoltaic (PV) panels are disclosed. A determination is made as to whether a reconnect condition, for reconnecting a PV panel to a power system from which the PV panel is disconnected, is satisfied. The PV panel is automatically reconnected to the power system responsive to determining that the reconnect condition is satisfied. A determination is then made as to whether a power system operating condition is satisfied on reconnection of the PV panel, and the PV panel is automatically disconnected from the power system responsive to determining that the power system operating condition is not satisfied on reconnection of the PV panel.

Claims

1. A method comprising:

determining whether a reconnect condition, for reconnecting a PhotoVoltaic (PV) panel to a power system from which the PV panel is disconnected, is satisfied;

automatically reconnecting the PV panel to the power system responsive to determining that the reconnect condition is satisfied;

determining whether a power system operating condition is satisfied on reconnection of the PV panel;

automatically disconnecting the PV panel from the power system responsive to determining that the power system operating condition is not satisfied on reconnection of the PV panel.

2. The method of claim 1,

the reconnect condition comprising a time condition,

the determining whether a reconnect condition is satisfied comprising determining whether a time period has elapsed after disconnection of the PV panel from the power system.

3. The method of claim 1,

the power system operating condition comprising a current flow condition,

the determining whether a power system operating condition is satisfied comprising determining whether there is at least a minimum magnitude of current flow in the power system.

4. The method of claim 3, the determining whether there is at least a minimum magnitude of current flow in the power system comprising measuring current flow in the power system over a time during which the PV panel remains reconnected on reconnection to the power system.

5. The method of claim 1,

the power system operating condition comprising a current pulse condition,

the determining whether a power system operating condition is satisfied comprising determining whether a current pulse is detected at the PV panel on reconnection of the PV panel to the power system.

6. The method of claim 1,

the reconnect condition comprising a connected PV panel limit condition,

the determining whether a reconnect condition is satisfied comprising determining whether a predetermined number of other PV panels are reconnected to the power system within a predetermined period of time.

7. The method of claim 6, the determining whether a predetermined number of other PV panels are reconnected to the power system within a predetermined period of time comprising detecting, at the PV panel, current pulses generated in the power system on reconnection of the other PV panels to the power system during the predetermined period of time.

8. The method of claim 6, the determining whether a predetermined number of other PV panels are reconnected to the power system within a predetermined period of time comprising detecting, at the PV panel, signals sent by other PV panels on reconnection of the other PV panels to the power system during the predetermined period of time.

9. The method of claim 8, further comprising:

broadcasting a signal from the PV panel on connection of the PV panel to the power system.

10. The method of claim 1,

the reconnect condition comprising a connected PV panel limit condition,

the determining whether a reconnect condition is satisfied comprising determining whether a predetermined minimum number of PV panels including the PV panel are ready to reconnect to the power system.

11. The method of claim 10, the determining whether the predetermined minimum of PV panels are ready to reconnect to the power system comprising detecting, at the PV panel, current pulses generated in the power system on reconnection of the other PV panels to the power system.

12. The method of claim 11,

the reconnect condition further comprising a current pulse condition,

the determining whether a reconnect condition is satisfied further comprising:

reconnecting the PV panel to the power system;

determining whether a current pulse is detected at the PV panel on reconnection of the PV panel to the power system;

disconnecting the PV panel from the power system on detection of a current pulse or expiry of a pulse detection time period;

determining that the reconnect condition is satisfied where a current pulse is detected at the PV panel during the pulse detection time period and the predetermined minimum of PV panels including the PV panel are ready to reconnect to the power system.

13. The method of claim 10, the determining whether the predetermined minimum of PV panels are ready to reconnect to the power system comprising detecting, at the PV panel, signals sent by other PV panels on reconnection of the other PV panels to the power system during the predetermined period of time.

14. The method of claim 13,

the reconnect condition further comprising a current pulse condition,

the determining whether a reconnect condition is satisfied further comprising:

reconnecting the PV panel to the power system;

determining whether a current pulse is detected at the PV panel on reconnection of the PV panel to the power system;

broadcasting a signal from the PV panel on detection of a current pulse during a pulse detection time period;

disconnecting the PV panel from the power system on detection of a current pulse or expiry of the pulse detection time period;

determining that the reconnect condition is satisfied where a current pulse is detected at the PV panel during the pulse detection time period and the predetermined minimum of PV panels including the PV panel are ready to reconnect to the power system.

15. The method of claim 10, the reconnecting comprising reconnecting the predetermined minimum number of PV panels to the power system on determining that the predetermined minimum of PV panels are ready to reconnect to the power system.

16. The method of claim 1,

the reconnect condition comprising a numeric value condition,

the determining whether a reconnect condition is satisfied comprising comparing a random number associated with the PV panel to a predefined value.

17. The method of claim 1,

the reconnect condition comprising receipt of a connect command from a grid sensor coupled to the power system,

the determining whether a reconnect condition is satisfied comprising determining whether the connect command is received.

18. A PhotoVoltaic (PV) panel disconnect switching arrangement comprising:

switches to control connection of the PV panel to a power system and bypass of the PV panel on disconnection of the PV panel from the power system;

a controller operatively coupled to the switches, to determine whether a reconnect condition for reconnecting the PV panel to the power system is satisfied, to automatically reconnect the PV panel to the power system responsive to determining that the reconnect condition is satisfied, to determine whether a power system operating condition is satisfied on reconnection of the PV panel, to automatically disconnect the PV panel from the power system responsive to determining that the power system operating condition is not satisfied on reconnection of the PV panel.

19. The PV panel disconnect switching arrangement of claim 18, the controller being configured to determine that the reconnect condition is satisfied where one or more of:

a time period has elapsed after disconnection of the PV panel from the power system;

a predetermined number of other PV panels are reconnected to the power system within a predetermined period of time;

a predetermined minimum number of PV panels including the PV panel are ready to reconnect to the power system;

a random number associated with the PV panel has a predetermined relationship to a predefined value;

a connect command is received from a grid sensor coupled to the power system.

20. The PV panel disconnect switching arrangement of claim 18, the controller being configured to determine that the reconnect condition is satisfied where one or more of:

there is at least a minimum magnitude of current flow in the power system;

a current pulse is detected at the PV panel on reconnection of the PV panel to the power system.

21. A method comprising:

detecting, at a PhotoVoltaic (PV) panel that is connected to a power system, a low current condition or an arc fault condition in the power system;

automatically disconnecting the PV panel from the power system responsive to detection of the low current condition or the arc fault condition.

22. The method of claim 21,

the detecting comprising independently detecting the low current condition or the arc fault condition at each of a plurality of PV panels, including the PV panel, that are connected to the power system,

the automatically disconnecting comprising independently automatically disconnecting each PV panel from the power system responsive to detection of the low current condition or the arc fault condition at each PV panel.

23. A PhotoVoltaic (PV) panel disconnect switching arrangement comprising:

switches to control connection of the PV panel to a power system and bypass of the PV panel on disconnection of the PV panel from the power system;

a controller operatively coupled to the switches, to detect a low current condition or an arc fault condition in the power system while the PV panel is connected to the power system, to automatically disconnect the PV panel from the power system responsive to detection of the low current condition or the arc fault condition.