Load breaker arrangement

• US 20090097172A1
• Filed: 09/30/2008
• Published: 04/16/2009
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: SMA Solar Technology AG
• Original Assignee: SMA Solar Technology AG
• Inventors: Bremicker, Sven, Buchhold, Stefan, Greizer, Frank, Cramer, Gunther
• Granted Patent: US 8,213,133 B2
• Time in Patent Office: Days
• US Class Current: 361/8
• CPC Class Codes: H01H 33/596 for interrupting dc
• CPC Class Codes: H01H 9/542 Contacts shunted by static switch means
• 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: Y02E 10/50 Photovoltaic [PV] energy

Abstract

The subject matter of the present invention is a load breaker arrangement (1) for switching on and off a DC current of a DC current circuit in a photovoltaic plant with a semiconductor switching element (4) to avoid a switching arc, there being provided an electronic control unit (5) configured such that one or more signals are received by the control unit, and the load breaker arrangement (1) being configured such that in at least one current-carrying line of the DC current circuit there is galvanic separation by a switching contact that is automatically controllable by the control unit (5) in the switched-off condition and one or more control signals being transmitted to the load breaker arrangement (1) and a semiconductor switching element (4) interrupting the DC current so that the switching contact is de-energized, whereby

• • the signals are flaw signals that are received in case of a flaw in the PV generator, inverter or on the AC side, the DC current circuit being automatically switched on or off by the control signals in case of at least one flaw,
  • said arrangement being configured such that, during switch off,
  • said semiconductor switching element (4) is at first closed in a first step,
  • the switching contacts (K1, K2) of a first switching means are opened in a second step for the DC current to flow through said semiconductor switching element (4),
  • said semiconductor switching element (4) being again opened in a third step and
  • switching contacts (K1, K2) of a second switching means being opened in order to cause galvanic separation to occur
  • and that an additional manually operable load breaker (8) is connected, said manually operable load breaker (8) being a manually breakable DC current connecting system with plug contacts for photovoltaic plants that is provided with an electronic arc quenching system.

Claims

1. A load breaker arrangement (1) for switching on and off a DC current of a DC current circuit in a photovoltaic plant with a semiconductor switching element (4) to avoid a switching arc, there being provided an electronic control unit (5) configured such that one or more signals are received by the control unit, and the load breaker arrangement (1) being configured such that in at least one current-carrying line of the DC current circuit there is galvanic separation by a switching contact that is automatically controllable by the control unit (5) in the switched-off condition and one or more control signals being transmitted to the load breaker arrangement (1) and a semiconductor switching element (4) interrupting the DC current so that the switching contact is de-energized, characterized in

that the signals are flaw signals that are received in case of a flaw in the PV generator, inverter or on the AC side, the DC current circuit being automatically switched on or off by the control signals in case of at least one flaw, said arrangement being configured such that, during switch off,

said semiconductor switching element (4) is at first closed in a first step,

the switching contacts (K1, K2) of a first switching means are opened in a second step for the DC current to flow through said semiconductor switching element (4),

said semiconductor switching element (4) being again opened in a third step and

switching contacts (K1, K2) of a second switching means being opened in order to cause galvanic separation to occur

and that an additional manually operable load breaker (8) is connected, said manually operable load breaker (8) being a manually breakable DC current connecting system with plug contacts for photovoltaic plants that is provided with an electronic arc quenching system.

2. The load breaker arrangement as set forth in claim 1, characterized in that, in the current-carrying line of the DC current circuit, there are arranged two switching means that are switchable one after the other through control signals, said switching means having switching contacts (K1, K2), in particular two relays (R1, R2), in such a manner that on the one side one of the switching means is bridged by the semiconductor switching element (4) for the DC current to be switched off by opening the semiconductor switching element (4), and that on the other side galvanic separation of the DC current circuit occurs through the other switching means.

3. The load breaker arrangement as set forth in claim 2, characterized in that one of the switching means is mounted in series with the semiconductor switching element (4).

4. The load breaker arrangement as set forth in claim 2,

characterized in that the switching contacts of the switching means are connected in series.

5. The load breaker arrangement as set forth in claim 2,

characterized in that a third switching means with switching contacts (K1, K2) is connected in another current-carrying line of the DC current circuit.

6. The load breaker arrangement as set forth in claim 1,

characterized by at least two relays (R1, R2, R3).

7. The load breaker arrangement as set forth in claim 1,

characterized in that switching on or off occurs in the event of:

an overcurrent,

an overvoltage,

too high a temperature,

fire in an apparatus,

a flaw in an apparatus,

a manuel switch-off command,

an external electrical command,

opening of a cover of the apparatus,

failure of a public low-voltage utility grid and/or

theft of the photovoltaic plant.

8. The load breaker arrangement as set forth in claim 1, characterized in that an external control line (6) of the control unit (5) is provided and that the control unit (5) is arranged outside of the load breaker arrangement (1), in particular in a solar inverter, or that said control unit (5), in particular a flaw detection unit, is integrated in a control electronics of the load breaker arrangement (1).

9. The load breaker arrangement as set forth in claim 1,

characterized in that a voltage supply of the load breaker arrangement occurs both from a DC side and from an AC side.

10. The load breaker arrangement as set forth in claim 3,

characterized in that the switching contacts of the switching means are connected in series.

11. The load breaker arrangement as set forth in claim 4,

characterized in that a third switching means with switching contacts (K1, K2) is connected in another current-carrying line of the DC current circuit.