JP2013201871A - Power converter - Google Patents

Abstract

To provide a power converter capable of continuing power supply to a consumer load while protecting a construction worker and the like from the risk of electric shock even if a power failure occurs in an interconnected distribution system.
In a power converter that outputs converted AC power to a plurality of AC loads and a commercial distribution system via a switch, independent operation is performed by measuring a voltage in a connection line between the switch and the distribution system. Means for tripping a circuit breaker with an external trip function provided on the distribution system side of the plurality of AC loads in the connection line without opening the switch when detected.
[Selection] Figure 1

Description

  The present invention relates to a power converter for a photovoltaic power generation apparatus.

  The power converter for a photovoltaic power generation apparatus targeted by the present invention converts the DC power generated by the photovoltaic power generation apparatus into AC power and supplies it to a plurality of AC loads and commercial distribution systems of consumers. The output end of the power converter is connected to a commercial power distribution system via a switch, and a plurality of AC loads, which are consumer loads, are connected in parallel to the connection line between the switch and the commercial power distribution system. It is connected.

  By the way, in a power distribution system operated by an electric power company, a power failure may occur due to construction or the like. In this case, if electric power is supplied from the power converter to the construction section of the distribution system, there is a risk that a construction worker or the like may receive an electric shock.

  Therefore, conventional power converters for photovoltaic power generation equipment monitor the phase of the system voltage in the connection line between the switch and the commercial power distribution system, etc., and if a power failure occurs in the power distribution system, an independent operation is generated. As detected, the switch is opened and the power converter is disconnected from the distribution system so that no power is output to the power distribution system that is out of power.

JP 2003-319560 A

  However, when a power failure occurs in the power distribution system, if the power converter stops output, the customer load is stopped due to the absence of power supply.

  The present invention has been made in view of the above, and even if a power failure occurs in the interconnected distribution system, the power supply to the consumer load is continued while protecting the construction workers and the like from the risk of electric shock. An object is to obtain a power converter that can be used.

  In order to solve the above-described problems and achieve the object, the present invention provides a power converter that outputs converted AC power to a plurality of AC loads and a commercial power distribution system via a switch. A circuit breaker with an external trip function provided on the power distribution system side of the plurality of AC loads in the connection line without opening the switch when a single operation is detected by voltage measurement in a connection line between the system and the system A means for tripping is provided.

  According to the present invention, even if a power failure occurs in the interconnected distribution system, the power supply to the consumer load can be continued while protecting the construction worker and the like from the risk of electric shock. .

FIG. 1 is a block diagram showing a configuration of a power converter according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a configuration of a power converter according to Embodiment 2 of the present invention.

  Embodiments of a power converter according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a power converter according to Embodiment 1 of the present invention. In FIG. 1, a solar cell array 1 is a solar power generation apparatus installed as a private power generator for the purpose of supplying self-demanded electric power to consumers such as factories, hospitals, and hotels.

  The DC power generated by the solar cell array 1 is input to the power converter 3 via the connection box 2. The power converter 3 includes a main circuit unit 3a including a converter unit that boosts an input voltage and an inverter unit that converts the input voltage into AC power. One end of the power converter 3 is connected to an output end of the main circuit unit 3a. In addition to the switch 3b connected to the panel 4, an independent operation control unit 3c according to the first embodiment is provided. The switch 3b is configured by a relay or an electromagnetic switch.

  The distribution board 4 has a photovoltaic power generation breaker 5 having one end connected to the other end of the switch 3b, a distribution line 6 having one end connected to the other end of the photovoltaic power generation breaker 5, and a distribution line 6 A plurality of branch circuit breakers 7 having one end connected in parallel to each other, a circuit breaker 8 with an external trip function whose one end is connected to the other end of the distribution line 6, and one end at the other end of the circuit breaker 8 with an external trip function Is connected to a current limiter 9 to which is connected. And the system voltage observation point 10 is set to the connection line of the other end of the circuit breaker 8 with an external trip function, and the one end of the current limiter 9, and is connected to the control part 3c at the time of an independent operation. The other end of each of the plurality of branch breakers 7 is connected to an AC load of a consumer (hereinafter simply referred to as “load”). The other end of the current limiter 9 is connected to a power distribution system 11 operated by the power company.

  In the above configuration, first, general operations will be briefly described. The photovoltaic power generation breaker 5 and the current limiter 9 arranged on the distribution board 4 are opened and closed by the customer, but are normally closed. Moreover, the circuit breaker 8 with an external trip function attaches the function which trips with an external signal to the earth leakage circuit breaker, for example, and the normal operation control part 3c operates in the normal time when the power failure has not occurred in the distribution system 11 The circuit is closed. Moreover, the branch circuit breaker 7 corresponding to the load to be operated among the plurality of branch circuit breakers 7 is closed at the start of operation. The switch 3b of the power converter 3 is also closed at the start of operation.

  The power converter 3 receives supply of DC power from the solar cell array 1, boosts the DC voltage, converts it to AC power, and supplies AC power to a plurality of loads via the switch 3b. The electric power generated by the solar cell array 1 is affected by sunshine hours, amount of solar radiation, solar radiation intensity, and the like. Therefore, when the AC power converted and output by the power converter 3 is insufficient for the required power amount of the plurality of loads, the shortage is supplied from the distribution system 11 to the plurality of loads. In addition, when the AC power converted and output by the power converter 3 exceeds the required power amount of a plurality of loads, the surplus is output to the distribution system 11.

  During such interconnection operation, the independent operation control unit 3c of the power converter 3 monitors the phase of the system voltage Vg at the system voltage observation point 10, and a power failure occurs in the distribution system 11, causing the power converter 3 to operate. Is detected, the circuit breaker 8 with the external trip function is tripped without opening the switch 3b, and the plurality of loads and the power converter 3 are disconnected from the distribution system 11.

  Thereby, since the electric power is continuously supplied from the power converter 3 to the plurality of loads of the consumer, the operation can be continued even if the power distribution system 11 fails. In addition, since AC power is not supplied from the power converter 3 to the power distribution system 11 that is out of power, it is possible to protect construction workers and the like from the risk of electric shock.

  As described above, according to the first embodiment, even if a power failure occurs in the interconnected distribution system, power supply to the consumer load continues while protecting the construction workers and the like from the risk of electric shock. A power converter for a photovoltaic power generation device that can be obtained is obtained.

Embodiment 2. FIG.
FIG. 2 is a block diagram showing a configuration of a power converter according to Embodiment 2 of the present invention. In FIG. 2, components that are the same as or equivalent to the components shown in FIG. 1 (Embodiment 1) are assigned the same reference numerals. Here, the description will be focused on the portion related to the second embodiment.

  In FIG. 2, the power converter according to the second embodiment is provided with an independent operation control unit 3d in place of the independent operation control unit 3c in the configuration shown in FIG. 1 (Embodiment 1). Other configurations are the same as those in FIG.

  Some of the customer's loads may be problematic if the power supply is interrupted. On the other hand, the power generated by the solar cell array 1 is affected by the sunshine time, the amount of solar radiation, and the intensity of solar radiation. Therefore, priorities are determined for each of a plurality of loads in accordance with the importance, and a disjunctive load table that associates the amount of power output to the power distribution system according to the priorities with the load that does not operate at that amount of power It is set in the operation control unit 3d.

  As described in the first embodiment, the single operation control unit 3d detects the single operation, trips the circuit breaker 8 with the external trip function, and solves the plurality of loads and the power converter 3 from the distribution system 11. If it is arranged (operation of the control unit 3c at the time of single operation), the DC power amount to be converted or the converted AC power amount is acquired from the main circuit unit 3a, and a load to be disconnected is determined based on the reference load table based on the acquired DC power amount. The branch circuit breaker 7 corresponding to the low priority load to be disconnected is opened.

  As described above, according to the second embodiment, a load having a low priority is disconnected in accordance with the amount of AC power output during the single operation of the power converter for the photovoltaic power generator. Power supply performance can be improved.

  As described above, the power converter according to the present invention continues to supply power to the customer load while protecting the construction workers from the risk of electric shock even if a power failure occurs in the interconnected distribution system. It can be used as a power converter for a solar power generation device.

DESCRIPTION OF SYMBOLS 1 Solar cell array 2 Connection box 3 Power converter 3a Main circuit part 3b Switch 3c, 3d Control unit at the time of independent operation 4 Distribution board 5 Solar power generation breaker 6 Distribution line 7 Branch breaker 8 Circuit breaker with external trip function 9 Current limiter 10 System voltage observation point 11 Distribution system

Claims (2)

In a power converter that outputs converted AC power to multiple AC loads and commercial distribution systems via a switch,
When a single operation is detected by voltage measurement in a connection line between the switch and the power distribution system, the switch is not opened, and is provided on the power distribution system side of the plurality of AC loads in the connection line. A power converter comprising means for tripping a circuit breaker with an external trip function. Depending on the amount of AC power output to the distribution system via the switch, the switch is connected in parallel between the switch and the circuit breaker with external trip function in the connection line. The power converter according to claim 1, further comprising means for selectively opening a circuit breaker corresponding to an AC load having a low priority among the plurality of AC loads.

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