JP5645864B2 - Three-phase unbalance suppression system - Google Patents

Description

  The present invention relates to a three-phase unbalance suppression system that suppresses unbalance of a high-voltage three-phase distribution line connected to a load or a distributed power source.

A single-phase load connection to a high-voltage three-phase distribution line is made to any two phases in the three phases, but in an actual system, the single-phase load is concentrated and connected to a specific two-phase. Sometimes. In such a case, an unbalanced state of the three-phase load current is caused, and the utilization efficiency of the power equipment is deteriorated, or the load such as the three-phase induction motor is affected. In order to reduce the unbalance of such a three-phase distribution line, the connection phases of some loads are switched.
The conventional load switching device is equipped with a switch in parallel with the cutting point of each phase of the three-phase distribution line, and between the point on the power supply side from the cutting point of each phase and the point on the load side from the cutting point of the other phase. Install a contactless switch. Then, three-phase switching is performed by closing the contactless switch at a high speed following the opening of the switch (see, for example, Patent Document 1).

JP-A-6-165389

In recent years, the number of distributed power sources such as solar power generation facilities installed in homes and small-lot customers has increased rapidly. Such a distributed power source is connected to any two phases in the three phases of the three-phase distribution line, and the capacity thereof is larger than that of the normal load, so that an unbalanced state of the three-phase load current is further caused. In order to suppress the imbalance of the load current of the three-phase distribution line, it is necessary to switch the load and the connection phase of the distributed power source such as the solar power generation device.
In Patent Document 1, the connection phase of the load is switched at high speed by closing the contactless switch at high speed following the opening of the switch. However, a short interruption of power is inevitable at the time of switching, and it has been impossible to switch the load and the connection phase of the distributed power source with high reliability.

  The present invention was made to solve the above-described problems, and switches the load connected to the three-phase distribution line and the connection phase of the distributed power source with high reliability without causing a power failure at the time of switching. Thus, an object of the present invention is to provide a three-phase unbalance suppression system that can suppress unbalance of a three-phase load current.

A three-phase unbalance suppression system according to the present invention is a system for suppressing three-phase unbalance in a three-phase distribution line to which a plurality of devices consisting of a load or a distributed power source are connected, wherein the plurality of devices are arranged in the three-phase distribution. It is connected to the three-phase distribution line via a plurality of transformers each having a high voltage side connected to a predetermined two phases in the three phases of the electric wires. The three-phase unbalance suppression system includes a phase current detector that detects each phase current of the three-phase distribution line, and a first wire connected to a wiring between the low-voltage side of each transformer and the device. Based on the detection results of the switching device, the bypass line connecting between the low-voltage side wires of each of the transformers, the second switching device connected to the bypass line, and the phase current detector, A control device that controls two switching devices, and each of the bypass lines is a low voltage side of two transformers having different combinations of predetermined two phases to which the high voltage side is connected among the plurality of transformers , It is intended for coupling together between the apparatus-side wiring than the respective connected the first switching device, the first, second switching device, a first in series connected to the wiring or the bypass line A current limiting element and a second switch In which series body is configured by parallel connection.

  According to the above three-phase unbalance suppression system, the load phase connected to the three-phase distribution line or the connected phase of the equipment consisting of distributed power supplies can be switched reliably without any power failure during switching to suppress the three-phase load current unbalance. it can.

It is a block diagram which shows the three-phase imbalance suppression system by Embodiment 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the whole outline | summary of the three-phase imbalance suppression system by Embodiment 1 of this invention. It is a figure which shows the structure of the 1st, 2nd switching apparatus by Embodiment 1 of this invention. It is a figure which shows the timing chart used for operation | movement description of the three-phase imbalance suppression system by Embodiment 1 of this invention. It is a figure which shows the connection of the switching apparatus by Embodiment 3 of this invention. It is a figure which shows the whole 3 phase imbalance suppression system by Embodiment 4 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below.
1 is a block diagram showing a three-phase unbalance suppression system according to Embodiment 1 of the present invention, and FIG. 2 is a diagram showing an overall outline of the three-phase unbalance suppression system.
As shown in FIG. 1, the power system includes a high-voltage three-phase distribution line 1 of 6.6 kV, for example. 2b, 2c are connected. Each transformer 2a, 2b, 2c is, for example, a single-phase three-wire system in which the high-voltage side (primary side) is connected to the three-phase distribution line 1, and the transformer 2a that becomes an AB transformer is in A phase and B phase, The transformer 2b, which is a BC transformer, is connected to the B phase and the C phase, and the transformer 2c, which is a CA transformer, is connected to the C phase and the A phase, that is, the combination of the two connected phases is different. Also, the low-voltage side (secondary side) of each transformer 2a, 2b, 2c is supplied from a single-phase 100V or a single-phase 200V load x of general households and small consumers, or a distributed power source y such as a photovoltaic power generator. The devices 100a, 100b, and 100c are connected.

  The three-phase unbalance suppression system includes a first switching device 200a, 200b, 200c connected to a wiring between the low voltage side of each transformer 2a, 2b, 2c and the devices 100a, 100b, 100c, Bypass lines 500a and 500b connecting between the low voltage side wires of the transformers 2a, 2b, and 2c, and second switching devices 300a and 300b connected to the bypass lines 500a and 500b are provided.

  The bypass line 500a includes a device 100a between the low-voltage side wiring of the transformer 2a (AB transformer) and the low-voltage side wiring of the transformer 2b (BC transformer) rather than the first switching devices 200a and 200b. Connect at the point on the 100b side. Further, the bypass line 500b is a device 100b between the low-voltage side wiring of the transformer 2b (BC transformer) and the low-voltage side wiring of the transformer 2c (CA transformer) rather than the first switching devices 200b and 200c. , 100c side. That is, the two transformers (2a, 2b) and (2b, 2c) on both sides of each bypass line 500a, 500b differ in the combination of the two phases connected to the high voltage side.

  Furthermore, the three-phase unbalance suppression system detects a current flowing in the low-voltage side of the phase current detector 3 that detects each phase current in the three-phase load current of the three-phase distribution line 1 and each of the transformers 2a, 2b, and 2c. Current detectors 810a, 810b, and 810c as transformer current detectors, and a control terminal 6 such as a PC, a server, and other monitoring devices are provided as a control device that performs monitoring control. Moreover, the transmitter 4 which transmits each phase current detected by the phase current detector 3 to the control terminal 6, and the communication network 5 are provided. In this case, the current detectors 810a, 810b, and 810c cause the first switching devices 200a, 200b, and 200c to detect the currents on the transformers 2a, 2b, and 2c side of the first switching devices 200a, 200b, and 200c. Provided. The first switching devices 200a, 200b, and 200c are provided with transceivers 8a, 8b, and 8c, and the second switching devices 300a and 300b are provided with receivers 9a and 9b.

  Each phase current detected by the phase current detector 3 is transmitted from the transmitter 4 to the control terminal 6 via the communication network 5, and each transformer 2a detected by the current detectors 810a, 810b, 810c. 2b and 2c are transmitted to the control terminal 6 via the communication network 5 from the transceivers 8a, 8b and 8c. The control terminal 6 determines the devices 100a, 100b, and 100c to be switched based on the received current values, and the communication network 5 and the transceivers 8a, 8b, and 8c, and the receivers 9a and 9b. The switching command is given to the first switching devices 200a, 200b, 200c, and the second switching devices 300a, 300b via the, and the first and second switching devices 200a, 200b, 200c, 300a, 300b are controlled. To do.

  In the above description, the case where three transformers 2a, 2b, and 2c with different combinations of two connected phases are connected to one set of three-phase distribution lines 1 has been described for simplicity. As shown in FIG. 2, there are a large number of three-phase distribution lines 1-1n, and each three-phase distribution line 1-1n generally includes a large number of devices 100 (100a) via a large number of transformers 2 (2a, 2b,...). , 100b,... Are connected. Then, the first switching device 200 (200a, 200b,...) Is connected to the low-voltage side of each transformer 2, and the first switching device 200 of the two transformers 2 having different combinations of two connection phases is used. The wiring on the device 100 side is connected by a bypass line 500 (500a, 500b,...), And the second switching device 300 (300a, 300b,...) Is connected to each bypass line 500. The three-phase distribution lines 1 to 1n are supplied with power from a higher-voltage system power supply via the transformer 7.

FIG. 3 is a diagram illustrating a configuration of the first and second switching devices 200 and 300. The first switching device 200 is connected to the three wires as the low-voltage side wiring of each transformer 2, and the second switching device 300 is connected to the three wires of the bypass line 500, but has the same configuration. Reference numeral 8 denotes transceivers 8a, 8b, and 8c, 9 denotes receivers 9a and 9b, and the illustration of the current detector 810 (810a, 810b, 810c) provided in the first switching device 200 is omitted. .
As shown in FIG. 3, a first contactless switch 10 serving as a first switch is connected in series to two of the three wires, and a second contactless switch 11 serving as a second switch and a current limiting element. Are connected in parallel to the first contactless switch 10 respectively. In this case, only the contactless switch 13 is connected in series to the remaining one of the three wires, but the same configuration may be used for all three wires. If the remaining one wire is a three-phase single wire neutral wire, the switch may be omitted. The contactless switch 13 connected to the one line is controlled to be turned on / off so that the other two lines are turned on simultaneously.
The first and second contactless switches 10 and 11 and the contactless switch 13 are configured by bipolar semiconductor switches such as antiparallel thyristors and triacs, and the current limiting element may be a reactor or the like instead of the resistor 12.
In place of the first and second contactless switches 10 and 11 and the contactless switch 13, a contact switch can be used.

The operation of the three-phase unbalance suppression system configured as described above will be described below.
As described above, each phase current of the three-phase distribution line 1 is detected by the phase current detector 3 and transmitted from the transmitter 4 to the control terminal 6 via the communication network 5. Further, the current flowing to the low voltage side of each of the transformers 2a, 2b, 2c detected by the current detectors 810a, 810b, 810c is transmitted from the transceivers 8a, 8b, 8c to the control terminal 6 via the communication network 5. Sent to.
In the control terminal 6, the device 100 to be switched is determined based on the value of each received current, and the second transformer to be connected after switching is connected to the first transformer 2 to which the device 100 to be switched is connected. The two transformers 2 with the transformer 2 are determined from those in which the low voltage side wirings are connected to each other by the bypass line 500 in the plurality of transformers 2. Then, a switching instruction is generated so that the switching target device 100 is connected to the second transformer 2 to control the first and second switching devices 200 and 300.

A first example of the switching operation is shown below. In this example, the load amount connected to the BC phase is switched to the connection to the AB phase.
The load amount (power amount) of the device 100 connected to each of the two phases (AB phase, BC phase, CA phase) of the three-phase distribution line 1 is determined based on each phase current detected by the phase current detector 3. Table 1 shows the load amount before and after switching.

  In the stage before switching, the load amount of the device 100 connected to the AB phase is 4 kW, the load amount of the device 100 connected to the BC phase is -8 kW, and the load amount of the device 100 connected to the CA phase is -2 kW. is there. In this case, in the BC phase and the CA phase, there is a distributed power source y such as a solar power generator in the device 100, and the amount of power generation is larger than the amount of power consumption, and the value of the load amount is negative. The AB phase and the BC phase are unbalanced at 12 kW. If there is such a large variation between the phases, the power use efficiency is deteriorated and the load on the high-voltage three-phase motor or the like may be affected.

  The device 100b corresponding to the load amount of −6 kW connected to the BC phase is switched to be connected to the AB phase. Although details of the switching operation will be described later, the load amount connected to the AB phase, the BC phase, and the CA phase becomes −2 kW by switching, and the unbalance is eliminated. Moreover, since the power generation amount of the distributed power source y can be used in a system (different system) of another phase different from the original connection phase, consumption of commercial power can be suppressed.

Next, the detail of the operation | movement which switches the load amount for -6kW is demonstrated.
The control terminal 6 determines the device 100b corresponding to the load amount of −6 kW connected to the BC phase from the current flowing on the low voltage side of each transformer 2 detected by the current detector 810, and the device 100b is connected, that is, the transformer 2b before switching is defined as a first transformer. Then, the switched transformer 2a (second transformer) connected to the AB phase is determined. At this time, the first and second transformers 2b and 2a, which are two transformers, are bypass lines. The wiring on the low voltage side is connected to each other by 500a.
In this case, it is assumed that the device 100b connected to the transformer 2b (first transformer) in FIG. 1 is determined as a switching target. Then, the control terminal 6 transmits a switching command to the first and second switching devices 200a and 200b so that the device 100b is connected to the transformer 2a (second transformer) via the bypass line 500a. Switch.

In the state before switching, in the first switching devices 200a and 200b connected to the transformers 2a and 2b, the first contactless switch 10 and the contactless switch 13 are on, and the device 100a includes the transformer 2a. The device 100b is supplied with power via the transformer 2b.
FIG. 4 is a timing chart showing the operation of the first switching device 200b connected to the transformer 2b (first transformer) and the operation of the second switching device 300a. In the first switching device 200a on the low voltage side of the transformer 2a (second transformer), there is no change before and after switching.

When receiving the switching command from the control terminal 6, the second switching device 300a turns on the second contactless switch 11 and the contactless switch 13 to conduct the bypass line 500a. Since the transformer 2a is connected to the AB phase and the transformer 2b is connected to the BC phase and is of a different system, a cross current flows through the bypass line 500a, but the second contactless switch 11 of the second switching device 300a. The current is limited by the action of the resistor 12 connected in series to prevent overcurrent.
Next, when the first switching device 200b connected to the transformer 2b turns off the first contactless switch 10 and the contactless switch 13, the cross current path is cut off and the power supply from the transformer 2b is not supplied. Stopped. At this stage, power is supplied to the device 100b only from the transformer 2a via the bypass line 500a.
Subsequently, the second switching device 300a turns on the first contactless switch 10 and then turns off the second contactless switch 11, so that the resistor 12 is removed from the current path and the transformer 2a Power is supplied to the device 100b.

These series of operations are set to operate at a specified time difference by a built-in timer or sequencer. As shown in FIG. 4, the second contactless switch 11 of the second switching device 300a is turned on, and the first contactless switch 10 of the first switching device 200b is turned off. That is, since the overlap time t1 in which power is supplied to the device 100b from the two transformers 2a and 2b occurs, the power supply to the device 100b is interrupted even if the power supply from the transformer 2b is interrupted thereafter. There is no instantaneous power outage. In addition, since the overlap time t2 is provided when switching from the second contactless switch 11 to the first contactless switch 10 in the first switching device 200b, similarly, power is supplied without causing an instantaneous power failure. Can continue.
In this way, the connection phase of the device 100 can be switched with high reliability without causing a power failure at the time of switching, and the unbalance of the three-phase load current can be suppressed. Moreover, by suppressing the three-phase imbalance, it is possible to maintain a highly efficient state of power use with high reliability.

  In addition, the first switching device 200 is provided on the low voltage side of the transformer 2, and further, a bypass line 500 is arranged on the device 100 side from the first switching device 200, and the connection phase of the device 100 is connected to the low voltage side of the transformer 2. Therefore, the number of operating transformers 2 can be reduced by switching the device 100. Moreover, although the transformer 2 has no load loss even in the case of a light load, it is possible to reduce the overall no-load loss and reduce the loss by switching the device 100 and reducing the number of operating transformers 2 at a light load. it can.

Next, a second example of the switching operation is shown. In this example, the load amount connected to the AB phase is switched to the connection to the BC phase. Table 2 shows load amounts before and after switching.
In the stage before switching, the load amount of the device 100 connected to the AB phase is −8 kW, the load amount of the device 100 connected to the BC phase is 4 kW, and the load amount of the device 100 connected to the CA phase is −2 kW. is there. Similar to the first example, the unbalance is 12 kW. In this case, the device 100 a corresponding to the load amount of −6 kW connected to the AB phase is switched to the connection to the BC phase. Equilibrium is canceled.

  In this case, the switching target device 100a, the transformer 2a before switching (first transformer), and the transformer 2b after switching (second transformer) are determined by the control terminal 6, and the first terminal Similar to the example, the connection of the device 100a is switched from the first transformer 2a to the second transformer 2b. Here, the control terminal 6 performs switching control between the first switching device 200a connected to the transformer 2a (first transformer) and the second switching device 300a.

Next, a third example of the switching operation is shown. In this example, the load amount connected to the BC phase is switched to the connection to the CA phase. Table 3 shows the load amount before and after switching.
In the stage before switching, the load amount of the device 100 connected to the AB phase is −2 kW, the load amount of the device 100 connected to the BC phase is 8 kW, and the load amount of the device 100 connected to the CA phase is 4 kW. . As in the first example, the unbalance is 12 kW, but in this case, the device 100b corresponding to the load amount of -6 kW connected to the BC phase is switched to the CA phase to switch the unbalance. Equilibrium is canceled.

  In this case, the device 100b to be switched, the transformer 2b before switching (first transformer), and the transformer 2c after switching (second transformer) are determined by the control terminal 6, and the first Similar to the example, the connection of the device 100b is switched from the first transformer 2b to the second transformer 2c. Here, the control terminal 6 switches and controls the first switching device 200b connected to the transformer 2b (first transformer) and the second switching device 300b.

Next, a fourth example of the switching operation is shown. In this example, the load amount connected to the CA phase is switched to the connection to the BC phase. Table 4 shows the load amount before and after switching.
In the stage before switching, the load amount of the device 100 connected to the AB phase is −2 kW, the load amount of the device 100 connected to the BC phase is 4 kW, and the load amount of the device 100 connected to the CA phase is −8 kW. is there. Similar to the first example, the unbalance is 12 kW. In this case, the device 100c corresponding to the load amount of -6 kW connected to the CA phase is switched to the connection to the BC phase. Equilibrium is canceled.

  In this case, the switching target device 100c, the transformer 2c before switching (first transformer), and the transformer 2b after switching (second transformer) are determined by the control terminal 6, and the first terminal Similar to the example, the connection of the device 100c is switched from the first transformer 2c to the second transformer 2b. Here, the control terminal 6 performs switching control between the first switching device 200c connected to the transformer 2c (first transformer) and the second switching device 300b.

Next, a fifth example of the switching operation is shown. In this example, the load amount connected to the AB phase is switched to the connection to the CA phase. Table 5 shows load amounts before and after switching.
In the stage before switching, the load amount of the device 100 connected to the AB phase is −8 kW, the load amount of the device 100 connected to the BC phase is −2 kW, and the load amount of the device 100 connected to the CA phase is 4 kW. is there. As in the first example, the unbalance is 12 kW. In this case, by switching the device 100a corresponding to the load amount of -6 kW connected to the AB phase to connect to the CA phase, The imbalance is eliminated.

  In this case, a two-stage switching operation of a first switching operation and a second switching operation is performed. In the first switching operation, the device 100a connected to the AB phase is switched to the BC phase as in the second example, and then connected to the BC phase by the second switching operation as in the third example. Switch the device 100b to the CA phase. However, the transformer 2 after switching in the first switching operation and the transformer 2 before switching in the second switching operation are both connected to the BC phase, but are usually different transformers.

Next, a sixth example of the switching operation is shown. In this example, the load amount connected to the CA phase is switched to the connection to the AB phase. Table 6 shows the load amount before and after switching.
In the stage before switching, the load amount of the device 100 connected to the AB phase is 4 kW, the load amount of the device 100 connected to the BC phase is -2 kW, and the load amount of the device 100 connected to the CA phase is -8 kW. is there. As in the first example, the unbalance is 12 kW. In this case, by switching the device 100c corresponding to the load amount of −6 kW connected to the CA phase to connect to the AB phase, The imbalance is eliminated.

  In this case, a two-stage switching operation of a first switching operation and a second switching operation is performed. In the first switching operation, the device 100c connected to the CA phase is switched to the BC phase as in the fourth example, and then connected to the BC phase by the second switching operation as in the first example. The device 100b to be operated is switched to the AB phase. However, the transformer 2 after switching in the first switching operation and the transformer 2 before switching in the second switching operation are both connected to the BC phase, but are usually different transformers.

  In each switching operation of the first to sixth examples, the switching target device 100 is directly connected to the first transformer 2 before switching (not via the bypass line 500). It is connected to the second transformer 2 via 500. At that time, after the second non-contact switch 11 in the second switching device 300 connected to the bypass line 500 is turned on, the first non-switching in the first switching device 200 connected to the first transformer 2 is performed. After the contact switch 10 is turned off, and then the first contactless switch 10 in the second switching device 300 is turned on, the second contactless switch 11 in the second switching device 300 is turned off. Thereby, the connection phase of the apparatus 100 can be switched reliably without a power failure at the time of switching, and the unbalance of the three-phase load current can be suppressed.

  In the above embodiment, the current detector 810 that detects the current flowing on the low-voltage side of each transformer 2 is used when the number of transformers 2 is small or when the difference in load amount between transformers is small. It is not necessary. In that case, the control terminal 6 determines the device 100 to be switched based on the detection result of the phase current detector 3.

  In the above embodiment, only the single-phase three-wire transformer 2 is shown, but a three-phase three-wire transformer may be used. For example, when the transformer 2 connected to the two phases of the three-phase distribution line 1 has a light load, switching the device 100 connected to the transformer 2 to be connected to the three-phase three-wire transformer, Loss can be reduced by reducing the number of operating transformers 2 while suppressing imbalance in the three-phase load current.

Embodiment 2. FIG.
In the first embodiment, the device 100 to be switched is connected to the second transformer 2 via the bypass line 500 after switching. However, in the second embodiment, the reverse case, that is, The case of returning to the original connection state not via the bypass line 500 is shown.
A case where the switching is returned to the original state using the first example of the first embodiment will be described below.
At the stage where the switching in the first example is completed, power is supplied to the device 100b from the transformer 2a via the bypass line 500a. The first switching device 200a connected to the transformer 2a and the second switching device 300a connected to the bypass line 500a are both in the state where the first contactless switch 10 and the contactless switch 13 are on. In the first switching device 200b connected to 2b, all the switches, that is, the first and second contactless switches 10, 11 and the contactless switch 13 are in the OFF state.

Thereafter, the load amount (power amount) of the device 100 connected to each of the two phases (AB phase, BC phase, CA phase) of the three-phase distribution line 1 fluctuates, and the load amount connected to the AB phase is large. When the load amount connected to the phase becomes small, the load amount connected to the AB phase needs to be switched to the BC phase.
Also in this case, the control terminal 6 determines the switching target device 100b from the current detected by the current detector 810. In this case, the determined device 100b is connected from the transformer 2a via the bypass line 500a. Assume that power is supplied. The device 100b is connected, that is, the transformer 2a before switching is set as the first transformer, and the transformer 2b after switching (second transformer) connected to the BC phase is determined. At this time, in the first and second transformers 2a and 2b, which are two transformers, the low-voltage side wiring is connected to each other by the bypass line 500a.

Then, the control terminal 6 controls the first and second switching devices 200 and 300 to change the device 100b connected via the bypass line 500a from the transformer 2a connected to the AB phase to the original state. I.e., switching to the BC phase.
When receiving a switching command from the control terminal 6, the first switching device 200b connected to the second transformer 2b turns on the second contactless switch 11 and the contactless switch 13. At this time, since the bypass line 500a is conductive, the transformer 2a is connected to the AB phase, and the transformer 2b is connected to the BC phase, a cross current flows through the bypass line 500a. 11, the current is limited by the action of the resistor 12 connected in series to prevent overcurrent.
Next, when the first contactless switch 10 and the contactless switch 13 of the second switching device 300a connected to the bypass line 500a are turned off, the bypass line 500a is cut off and the cross current path is also cut off. Subsequently, in the first switching device 200b, the first contactless switch 10 is turned on and then the second contactless switch 11 is turned off, so that the resistor 12 is removed from the current path. Power is supplied to the device 100b. Note that the first switching device 200a connected to the first transformer 2a does not change before and after switching.

  In such a switching operation, the switching target device 100 is connected to the first transformer 2 via the bypass line 500 before switching, and is connected to the second transformer 2 after switching. At that time, after the second non-contact switch 11 in the first switching device 200 connected to the second transformer 2 is turned on, the first non-switching in the second switching device 300 connected to the bypass line 500 is performed. After the contact switch 10 is turned off and then the first contactless switch 10 in the first switching device 200 connected to the second transformer 2 is turned on, the second switch in the first switching device 200 is turned on. Turn off the contact switch. Thereby, the connection phase of the apparatus 100 can be switched reliably without a power failure at the time of switching, and the unbalance of the three-phase load current can be suppressed.

Embodiment 3 FIG.
In this embodiment, in addition to the three-phase unbalance suppression system shown in FIG. 1 of the first embodiment, wiring on the low voltage side between the transformer 2c that is a CA transformer and the transformer 2a that is an AB transformer is further provided. A bypass line 500c and a second switching device 300c connected to the bypass line 500c are provided. The bypass line 500c connects the low-voltage side wiring of the transformer 2c and the low-voltage side wiring of the transformer 2a at a point closer to the devices 100c and 100a than the first switching devices 200c and 200a.
Accordingly, the device 100a connected to the AB phase can be quickly switched to the CA phase, and the device 100c connected to the CA phase can be quickly switched to the AB phase by one switching operation.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described.
FIG. 6 is a diagram showing an overall outline of a three-phase imbalance suppression system according to Embodiment 4 of the present invention. As shown in the figure, the three-phase distribution line 1 is divided into a plurality of sections 1x, 1y, and 1z by a section switch 400 and managed. A plurality of devices 100 are connected to each of the sections 1x, 1y, and 1z via a plurality of transformers 2 having different combinations of two connected phases, and the first and second switching devices are the same as in the first embodiment. 200, 300 and a bypass line 500 are provided. Each section includes a phase current detector 3 and a transmitter 4 that detect each phase current of the sections 1x, 1y, and 1z. As described above, the portions corresponding to the sections 1x, 1y, and 1z of the three-phase unbalance suppression system share the control terminal 6 and the communication network 5, and are the same as those in the first embodiment.
The control terminal 6 monitors the unbalance of the three-phase load current for each section, and switches the connection phase of the device 100 with high reliability without causing a power failure when switching, as in the first embodiment. Suppresses phase load current imbalance.
Thus, for each of the divisions divided into a plurality of divisions, it is possible to suppress the unbalance of the three-phase load current, and it is possible to suppress the bias of the connection phase for each more detailed area. In addition, in the event of a power system failure, it is possible to quickly determine whether or not power can be accommodated in units of sections.

  It should be noted that within the scope of the invention, the embodiments can be freely combined, or the embodiments can be appropriately modified or omitted.

1 Three-phase distribution line, 2 transformer, 2a transformer (AB transformer),
2b transformer (BC transformer), 2c transformer (CA transformer), 3-phase current detector,
5 communication network, 6 control terminal,
10 a first contactless switch as the first switch;
11 Second contactless switch as second switch, 12 resistor,
100 (100a, 100b, 100c) equipment,
200 (200a, 200b, 200c) first switching device,
300 (300a, 300b, 300c) second switching device, 400 section switch,
500 (500a, 500b, 500c) bypass line,
810 (810a, 810b, 810c) a current detector as a transformer current detector,
x Load, y Distributed power source.

Claims (9)

In a three-phase unbalance suppression system that suppresses the three-phase unbalance of a three-phase distribution line connected to multiple devices consisting of loads or distributed power supplies,
The plurality of devices are connected to the three-phase distribution line through a plurality of transformers each having a high-voltage side connected to a predetermined two phases in the three phases of the three-phase distribution line,
A phase current detector for detecting each phase current of the three-phase distribution line;
A first switching device connected to the wiring between the low voltage side of each transformer and the device;
A bypass line connecting between the low-voltage side wires of each of the transformers and a second switching device connected to the bypass line;
A control device for controlling the first and second switching devices based on the detection result of the phase current detector;
Each of the bypass lines is more than the first switching device connected to each other on the low voltage side of the two transformers having different combinations of predetermined two phases to which the high voltage side is connected among the plurality of transformers. It connects the wiring on the equipment side to each other,
The first and second switching devices are configured by connecting a series body of a current limiting element and a second switch in parallel to a first switch connected in series to the wiring or the bypass line. A three-phase unbalance suppression system. The control device determines a device to be switched among the plurality of devices based on a detection result of the phase current detector, and connects to the first transformer to which the device is connected after switching. Two transformers, two transformers, are determined from those in which the low-voltage side wires are connected to each other by the bypass lines in the plurality of transformers, and the first and second switching devices are determined. The three-phase imbalance suppression system according to claim 1, wherein the system is controlled. The control device is connected to the bypass line when the device to be switched is directly connected to the first transformer without passing through the bypass line between the first and second transformers. After closing the second switch in the second switching device, the first switch in the first switching device connected to the first transformer is opened from the closed state, and then the second switch After closing the first switch in the switching device, the device is connected to the second transformer via the bypass line by opening the second switch in the second switching device. The three-phase imbalance suppression system according to claim 2, wherein the three-phase imbalance suppression system is switched. The control device is connected to the second transformer when the device to be switched is connected to the first transformer via the bypass line between the first and second transformers. After closing the second switch in the first switching device, the first switch in the second switching device connected to the bypass line is released from the closed state, and then the first switching is performed. After the first switch in the device is closed, the second switch in the first switching device is opened to switch the device to be connected to the second transformer. The three-phase imbalance suppression system according to claim 2. A transformer current detector for detecting the current flowing to the low-voltage side of each transformer,
The control device determines the device to be switched based on the detection result of the phase current detector and the detection result of the transformer current detector, and determines the first and second transformers. The three-phase unbalance suppression system according to any one of claims 2 to 4, wherein the system is determined. The plurality of transformers include an AB transformer connected to the A and B phases of the three phases A, B and C of the three-phase distribution line, and a BC transformer connected to the B and C phases. And a CA transformer connected to C and A phases, and the first switching device is connected to the low voltage side of the AB transformer, BC transformer, and CA transformer, respectively, and the AB transformer, BC The bypass line and the second switching device connected to the bypass line are respectively provided between the low-voltage side wires of the transformer and between the low-voltage side wires of the BC transformer and the CA transformer. The three-phase imbalance suppression system according to any one of claims 1 to 5. The three-phase according to claim 6, further comprising the bypass line and the second switching device connected to the bypass line between the low-voltage side wires of the CA transformer and the AB transformer. Unbalance suppression system. The three-phase distribution line has a plurality of sections divided by a section switch, and each section is connected to the plurality of devices via the plurality of transformers and includes the phase current detector. The said control apparatus suppresses the three-phase imbalance of the said three-phase distribution line for every said division, The three-phase imbalance suppression system of any one of Claim 1 to 7 characterized by the above-mentioned. . 9. The control device according to claim 1, wherein the control device acquires a detection result of the phase current detector via a communication network, and gives a control signal to the first and second switching devices. The three-phase unbalance suppression system of any one of Claims.

Images