Power switching system

Abstract

To provide a power supply changeover system that even in the case of occurence of an earthquake in a state in which a commercial power supply is stopped and a load operates using a distribution power supply, can cut off the load from the power supply.SOLUTION: A power supply changeover system comprises: a changeover switch 21 for performing changeover between a commercial power supply 4 and a storage battery 3 to supply power to a specific load; a seismoscope 23; and a control unit 24 for cutting off a power supply. The changeover switch 21 is connected with the secondary side of a trunk breaker 11 having the primary side to which the commercial power supply 4 is connected; and the specific load is connected to the output side of the changeover switch 21 via an earth leakage breaker 22. The control unit 24 includes: a relay 32 that makes both of the trunk breaker 11 and the earth leakage breaker 22 perform cut-off operation when sensing an earthquake; and a control section 35 for performing changeover control on the changeover switch 21. The control unit 24 receives supply of power from both of the commercial power supply 4 and the storage battery 3; and, when the commercial power supply 4 is stopped in a state in which the changeover switch 21 is connected to the commercial power supply 4, performs changeover of connection to the storage battery 3.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power supply switching system that switches the power supply of a load between a commercial power supply and a distributed power supply, and particularly to a power supply switching system having a seismic cutoff function.

Background Art

[0002] Conventionally, there has been a power supply switching system configured such that the power supply of some loads can be switched between a commercial power supply and a distributed power supply, and further including a seismic relay (seismic sensor) to cut off the load from the power supply when an earthquake occurs, thereby preventing the occurrence of an electrical fire. For example, in Patent Document 1, there is provided a distribution board equipped with a main breaker to which a commercial power supply is connected and a seismic relay, and a distributed power supply circuit section equipped with a switch for switching the power supply between the commercial power supply and the distributed power supply. When the seismic relay senses an earthquake, both the main breaker and the switch are cut off.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The power supply switching system of the above Patent Document 1 can cut off the load from the power supply in response to an earthquake and was effective in preventing an electrical fire. However, since the power supply of the seismic relay is supplied from the commercial power supply, when an earthquake occurs while the commercial power supply is out of power, the seismic relay does not operate. Therefore, a situation occurs where the power supply is not cut off when an earthquake occurs while the commercial power supply is out of power and the load is being driven by the distributed power supply.

[0005] Therefore, in view of such problems, an object of the present invention is to provide a power supply switching system that can cut off the load from the power supply even when an earthquake occurs while the commercial power supply has a power outage and the load is operating with a distributed power supply.

Means for Solving the Problems

[0006] To solve the above problems, the invention according to claim 1 includes a switching switch that switches the power supplied to a specific load between a commercial power supply and a distributed power supply, and a seismic control means having a function of detecting an earthquake and cutting off the power supply of all loads when an earthquake occurs. The power supply switching system is configured such that the switching switch has the secondary side of a main breaker to which the commercial power supply is connected to the primary side connected thereto and receives commercial power supply, and a specific load is connected to the output side of the switching switch via a leakage circuit breaker. Further, the seismic control means includes a cutoff operation unit that, when detecting an earthquake, causes both the main breaker and the leakage circuit breaker to perform a cutoff operation, and a switching control unit that performs switching control of the switching switch. The seismic control means receives power supply from both the commercial power supply and the distributed power supply, and when the commercial power supply has a power outage while the switching switch is connected to the commercial power supply, controls to switch the power supply of the specific load to the distributed power supply. According to this configuration, since the seismic control means is supplied with power from both the commercial power supply and the distributed power supply, even when the commercial power supply has a power outage and a specific load is operating with the distributed power supply, if an earthquake occurs, the seismic control means detects it and performs cutoff control. Therefore, even if an earthquake occurs while the commercial power supply has a power outage, all loads can be cut off from the power supply, ensuring safety. In addition, since the switching switch performs a switching operation and the power supply is switched from the commercial power supply to the distributed power supply in response to a power outage of the commercial power supply, the switching operation can be performed even without a function for monitoring the state of the commercial power supply in the switching switch, and power can be continuously supplied to a specific load.

[0007] In addition, in the above configuration, it is also conceivable to adopt a configuration in which the cutoff operation unit includes a first pseudo-leakage generation circuit that causes the leakage circuit breaker to perform a leakage cutoff operation and a second pseudo-leakage generation circuit that causes the main breaker to perform a leakage cutoff operation, and generates pseudo-leakage to cause a cutoff operation. By adopting this configuration, since the main breaker and the leakage circuit breaker are used to perform the interruption operation, only simple control is required. Also, in the above configuration, it is also conceivable to adopt a configuration in which the earthquake-sensitive control means has a leakage control unit that energizes and operates the first pseudo-leakage generation circuit immediately or after a certain time in response to the occurrence of an earthquake, while delaying the energization operation of the second pseudo-leakage generation circuit. By adopting this configuration, since the load on the output side of the changeover switch is first interrupted in response to the occurrence of an earthquake, if an electrical device dangerous to shaking is arranged on the output side of the changeover switch, it can be immediately turned off. On the other hand, since the main breaker does not immediately perform the interruption operation, it is possible to secure an evacuation route.

Advantages of the Invention

[0008] According to the present invention, since the earthquake-sensitive control means is supplied with power from the output side of the changeover switch, even if the commercial power supply fails and a specific load is operating by a distributed power source, when an earthquake occurs, the earthquake-sensitive control means senses it and performs the interruption control. Therefore, even if an earthquake occurs during a power outage of the commercial power supply, all loads can be disconnected from the power source, ensuring safety. In addition, in response to a power outage of the commercial power supply, the changeover switch performs a switching operation and the power source is switched from the commercial power supply to the distributed power source. Therefore, even if the changeover switch does not have a function of monitoring the state of the commercial power supply, it can perform the switching operation and continue to supply power to a specific load.

Brief Description of the Drawings

[0009]

Figure 1

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments embodying the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an example of a power supply switching system according to the present invention, which includes a distribution board 1 that supplies power to a load using a commercial power supply 4 as a power source, a switching board 2 that includes a switching switch 21 and supplies power from a power source selected by the switching switch 21 to a specific load, and a storage battery 3 as a distributed power source.

[0011] The distribution board 1 is assembled with a main breaker 11 and a plurality of branch breakers 12. A commercial power supply 4 consisting of single-phase three-wire is connected to the main breaker 11, and the branch breaker 12 is connected to the secondary side thereof. Loads (not shown) are respectively connected to the secondary sides of the branch breakers 12. In addition, the main breaker 11 is an ELB having a leakage protection function in addition to an overcurrent protection function.

[0012] In addition to the switching switch 21, the switching board 2 is assembled with a leakage breaker (ELB) 22, a seismic sensor 23 that senses an earthquake, a control unit 24, and a plurality of branch breakers 25. A specific load (not shown) is connected to this branch breaker 25, and the power selected by the switching switch 21 is supplied. The switching switch 21 includes two input terminals 21a and one output terminal 21b, and performs switching between two inputs by operating a switching handle (not shown), and one of them is connected to the output terminal 21b. In addition, it is provided with a switching control unit 21c that receives an external switching signal and switches the input. Even when the commercial power supply 4 experiences a power outage, a specific load connected to the branch breaker 25 is configured to continue operating using the storage battery 3 as a power source.

[0013] The seismic sensor 23 incorporates an acceleration sensor, and for example, when it senses shaking of seismic intensity 5 or more, it outputs a seismic sensing signal. This seismic sensing signal is transmitted to the control unit 24 via the transmission line S1. In addition, a power line S4 is connected to the secondary side of the leakage breaker 22 for the seismic sensor 23 to receive power supply.

[0014] The control unit 24 includes two relays 32 (a first relay 32a and a second relay 32b) that constitute a cutoff operation unit, a signal input unit 33 to which a detection signal is input, a sensor unit 34 that detects the circuit voltage, a control unit 35 composed of a microcomputer that controls the relay 32 and the changeover switch 21, and the like. The relay 32 has an a contact. The first relay 32a is arranged in parallel with the earth leakage circuit breaker 22 to form a first pseudo-earth leakage generation circuit W1 that generates a pseudo-earth leakage. The second relay 32b is arranged in parallel with the main breaker 11 to form a second pseudo-earth leakage generation circuit W2 that generates a pseudo-earth leakage. Thus, when the first relay 32a is turned on, the first pseudo-earth leakage generation circuit W1 becomes energized, and the earth leakage circuit breaker 22 determines that an earth leakage has occurred and performs an earth leakage cutoff operation. Also, when the second relay 32b is turned on, the second pseudo-earth leakage generation circuit W1 becomes energized, and the main breaker 11 determines that an earth leakage has occurred and performs an earth leakage cutoff operation.

[0015] The sensor unit 34 is a terminal that detects the voltages of two power supply circuits. A detection line S2 that detects a predetermined line voltage of the secondary side circuit S5 of the main breaker 11 to which commercial power is supplied and a detection line S3 that detects a predetermined line voltage of the output circuit S6 of the storage battery 3 are connected. Note that power is supplied to the control unit 24 via these detection lines S2 and S3.

[0016] The power supply switching system configured as described above operates as follows when an earthquake occurs. When the seismic sensor 23 detects an earthquake of a seismic intensity equal to or greater than a pre-set detection threshold, it outputs an earthquake detection signal. This earthquake detection signal is transmitted to the control unit 24 via the transmission line S1. When the control unit 35 receives the earthquake detection signal via the signal input unit 33, it starts the following control. First, it immediately turns on the first relay 32a. As a result, a pseudo-earth leakage occurs on the secondary side of the earth leakage circuit breaker 22, and the earth leakage circuit breaker 22 performs a cutoff operation.

[0017] On the one hand, the control unit 35 incorporates a timer. When it receives an earthquake detection signal from the earthquake sensor 23, the timer counts a predetermined time, and when the predetermined time has elapsed, it turns on the second relay 32b. As a result, a pseudo-leakage occurs on the secondary side of the main breaker 11, and the main breaker 11 performs a tripping operation. That is, a delay operation is carried out in which the main breaker 11 performs a tripping operation after a certain time has elapsed since the earthquake occurred.

[0018] Also, when the sensor unit 34 detects a power outage of the commercial power supply 4 while the changeover switch 21 is selecting the commercial power supply 4, the control unit 35 outputs a switching signal to the switching control unit 21c of the changeover switch 21 and switches the power supply connected to the output terminal 21b from the commercial power supply 4 to the storage battery 3. Further, when the commercial power supply 4 is restored while the power supply is switched to the storage battery 3, the sensor unit 34 detects this and performs control to return the connection of the input terminal 21a of the changeover switch 21 to the commercial power supply 4.

[0019] In this way, since the earthquake sensor 23 receives power supply from the output side of the changeover switch 21, even if the commercial power supply 4 experiences a power outage and a specific load is operating with the storage battery 3, the earthquake can be detected when an earthquake occurs. And since the control unit 24 is supplied with power from the commercial power supply 4 and the storage battery 3, when it receives an earthquake detection signal from the earthquake sensor 23, it performs cutoff control on the main breaker 11 and the leakage circuit breaker 22. Therefore, even if an earthquake occurs during a power outage of the commercial power supply 4, all loads can be cut off from the power supply, ensuring safety. Also, since the tripping operation is performed by utilizing the leakage cutoff function of the main breaker 11 and the leakage circuit breaker 22, there is no need to incorporate a new circuit, and simple control suffices. In addition, since the load on the output side of the changeover switch 21 is first cut off upon receiving an earthquake, dangerous electrical equipment with respect to shaking can be instantly turned off by connecting it as a specific load. On the other hand, since the main breaker 11 does not perform an immediate tripping operation, it is possible to secure an evacuation route. Also, upon receiving a power outage of the commercial power supply 4, the changeover switch 21 performs a switching operation and the power supply of a specific load is switched from the commercial power supply 4 to the storage battery 3. Therefore, even without a function for monitoring the state of the commercial power supply 4 in the changeover switch 21, it can perform a switching operation and continue to supply power to a specific load.

[0020] Also, in the above embodiment, the leakage circuit breaker 22 is immediately tripped when the earthquake detection signal from the earthquake sensor 23 is received. However, the leakage circuit breaker 22 may also be tripped after a certain period of time from the occurrence of an earthquake. And when the leakage circuit breaker 22 and the main breaker 11 are thus delayed in tripping operation, the earthquake sensor 23 itself may be delayed in operation so that the earthquake detection signal is output after a certain period of time from the detection of an earthquake. Further, although the earthquake sensor 23 and the control unit 24 are separate bodies, they may be integrated. Also, when there is a signal input section for separately tripping the main breaker 11 and the leakage circuit breaker 22, a signal output section that outputs a tripping signal to the signal input section may be provided instead of the first relay 32a and the second relay 32b. Also, although the distributed power source is the storage battery 3, it may be a power generation facility such as a solar power generation device or a fuel cell. Furthermore, although the changeover switch 21 and the control unit 24 are housed in a switchboard 2 separated from the distribution board 1, the switchboard 2 may be integrated with the distribution board 1 and all assembled in the distribution board 1.

Explanation of Reference Numerals

[0021] 1... Distribution board, 2... Switchboard, 3... Storage battery (distributed power source), 4... Commercial power source, 11... Main breaker, 12... Branch breaker, 21... Changeover switch, 22... Leakage circuit breaker, 23... Earthquake sensor (earthquake detection control means), 24... Control unit (earthquake detection control means), 25... Branch breaker, 32... Relay (tripping operation section), 33... Signal input section, 34... Sensor section, 35... Control section (leakage control section, changeover control section), W1... First pseudo-leakage generation circuit, W2... Second pseudo-leakage generation circuit.

Claims

【Claim 1】 A power supply switching system comprising a switching switch for switching the power supplied to a specific load between a commercial power supply and a distributed power supply, and a seismic control means having a function of detecting an earthquake and cutting off the power supply of all loads when an earthquake occurs, wherein the switching switch is connected to the secondary side of a main breaker to which the commercial power supply is connected to the primary side, and commercial power is supplied, and the specific load is connected to the output side of the switching switch via a leakage circuit breaker, and further, the seismic control means includes a cutoff operation unit for cutting off both the main breaker and the leakage circuit breaker when an earthquake is detected, and a switching control unit for switching and controlling the switching switch. The seismic control means receives power supply from both the commercial power supply and the distributed power supply, and when the commercial power supply fails while the switching switch is connected to the commercial power supply, controls to switch the power supply of the specific load to the distributed power supply. A power supply switching system characterized by this.

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