JP2001231167A - Method and apparatus for opening and closing capacitor equipment for three-phase alternating-current power - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent accidents such as dielectric breakdown of an alternating- current breaker when capacitor equipment for three-phase alternating-current power is turned off. SOLUTION: The method and apparatus are for opening and closing (turning on and off) a load of the capacitor equipment 3 for three-phase alternating- current power whose primary side is connected with a three-phase alternating- current power supply 1, and whose secondary side is in three-phase Y-connection with its neutral point grounded. The capacitor equipment 3 for three-phase alternating-current power is provided on the primary side with the alternating- current breaker 2 and further the capacitor equipment 3 for three-phase alternating-current power is provided on the secondary side with a switch 4. When the capacitor equipment 3 for three-phase alternating-current power is turned off, the switch 4 is released and then the alternating-current breaker 2 is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, load switching (ON / OFF) of capacitor equipment for three-phase AC power for the purpose of improving power factor or suppressing harmonics, for example, in power receiving and transforming facilities in power companies and factories. A method and apparatus for performing
Especially when turning off the three-phase AC power capacitor equipment,
The present invention relates to a method and an apparatus for opening and closing a three-phase AC power capacitor equipment capable of preventing a large voltage from being applied between the poles of an AC circuit breaker due to a potential shift of a neutral point and preventing an accident such as insulation breakdown of the AC circuit breaker. Things.

[0002]

2. Description of the Related Art Conventionally, for example, power receiving and transforming facilities in a power company and a factory are mainly provided with a three-phase AC power capacitor for the purpose of improving a power factor or suppressing harmonics.

[0003] Conventionally, load switching (ON / OFF) of such three-phase AC power capacitor equipment is performed only by opening and closing an AC circuit breaker.

FIG. 2 is a schematic diagram showing an example of a combination configuration of this type of conventional three-phase AC power capacitor equipment and its switchgear.

In FIG. 2, a primary side of a three-phase AC power capacitor facility 3 is connected to a three-phase AC power supply 1 via an AC circuit breaker 2.

On the secondary side of the three-phase AC power capacitor equipment 3, three phases are star-connected and the neutral point is grounded.

In the above configuration, the three-phase AC power capacitor equipment 3 supplied with power from the three-phase AC power supply 1 via the AC circuit breaker 2 is switched on / off (ON / OFF) by the AC circuit breaker 2. You.

Here, the three-phase AC power capacitor equipment 3
Has a neutral point because the three phases are star-connected. The potential at the neutral point is 0 (zero) volt because the three-phase AC power capacitor equipment 3 is in a three-phase equilibrium state while the capacitor equipment 3 is ON, but the AC circuit breaker 2 is tripped. Immediately after the operation is started, one phase is turned off, the other two phases are turned on, and a three-phase unbalanced state is established, so that the potential shifts (it is not 0 (zero) volt).

As a result, a large voltage is applied between the poles of the AC circuit breaker 2, which may lead to an accident such as insulation breakdown of the AC circuit breaker 2.

[0010]

As described above, in the prior art, the potential shift at the neutral point is superimposed on the residual charge of the capacitor immediately after the trip operation of the AC circuit breaker 2.
The voltage between the poles of the AC circuit breaker 2 becomes very large,
This may lead to an accident such as insulation breakdown of the AC circuit breaker 2.

An object of the present invention is to eliminate the potential shift at the neutral point with a simple configuration, so that when the three-phase AC power capacitor equipment is turned off, the potential shift at the neutral point causes a gap between the poles of the AC circuit breaker. It is an object of the present invention to provide a method and an apparatus for opening / closing a three-phase AC power capacitor equipment capable of preventing an accident such as insulation breakdown of an AC circuit breaker by preventing a large voltage from being applied to the AC power supply.

[0012]

In order to achieve the above object, according to the first aspect of the present invention, the primary side is connected to a three-phase AC power supply, the secondary side is connected to a three-phase star connection, and the neutral state is provided. In a method for switching the load (ON / OFF) of a three-phase AC power capacitor facility whose point is grounded, an AC circuit breaker is provided on the primary side of the three-phase AC power capacitor facility, and the three-phase AC power capacitor facility is provided. In order to turn off the three-phase AC power capacitor equipment, the switch is first tripped, and then the AC circuit breaker is tripped.

According to a second aspect of the present invention, there is provided a three-phase AC power capacitor system in which a primary side is connected to a three-phase AC power supply, a secondary side is connected in a three-phase star connection, and a neutral point is grounded. In an apparatus for performing load switching (ON / OFF), an AC circuit breaker provided on a primary side of a three-phase AC power capacitor facility, a switch provided on a secondary side of the three-phase AC power capacitor facility, When a request to turn off the three-phase AC power capacitor equipment is received from outside, a trip command is output to the switch, and the switch is turned off by the trip command.
And control means for controlling to output a tripping command to the AC circuit breaker on condition that the state is established.

Therefore, in the method and the apparatus for opening and closing the three-phase AC power capacitor equipment according to the first and second aspects of the present invention, the three-phase AC power capacitor equipment is connected
When the FF is performed, the AC circuit breaker is tripped after the switch is tripped, and immediately after the AC circuit breaker starts the trip operation, the three-phase star on the secondary side of the three-phase AC power capacitor equipment Since the connections are open and the three phases are not connected at the neutral point, the potential shift phenomenon at the neutral point is eliminated. Thereby, when turning off the three-phase AC power capacitor equipment,
By suppressing the voltage applied between the AC circuit breakers, it is possible to prevent accidents such as dielectric breakdown of the AC circuit breakers.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a combined configuration of a three-phase AC power capacitor facility according to the present embodiment and a switchgear thereof. The same parts as those in FIG. The description will be omitted, and only different portions will be described here.

That is, in the present embodiment, as shown in FIG. 1, a switch 4 is provided on the secondary side of the three-phase AC power capacitor equipment 3 shown in FIG. The control device 5 for controlling the tripping operation of the container 2 is provided.

When the control device 5 receives a request to turn off the three-phase AC power capacitor equipment 3 from the outside, the control device 5 outputs a trip command to the switch 4, and the switch 4 is turned off by the trip command. Control is performed so that a trip command is output to the AC circuit breaker 2 on condition that the state has been achieved.

Next, a method of opening and closing the three-phase AC power capacitor equipment 3 according to the present embodiment configured as described above will be described.

When turning off the three-phase AC power capacitor equipment, the O.P.
When receiving the FF request, the control device 5 first outputs a trip command to the switch 4.

Next, in response to a trip command to the switch 4, a "switch 4 OFF state" signal indicating that the switch 4 has been turned off is fed back.
Control device 5 outputs a trip command to AC circuit breaker 2.

According to the above procedure, when the three-phase AC power capacitor equipment 3 is turned off, immediately after the AC circuit breaker 2 starts the tripping operation, the three-phase AC power capacitor equipment 3 on the secondary side is turned off. Since the phase star connection is open and the three phases are not connected at the neutral point, the potential shift phenomenon of the neutral point as described above is eliminated.

Thus, when the three-phase AC power capacitor equipment 3 is turned off, the voltage applied between the poles of the AC circuit breaker 2 is suppressed to prevent an accident such as insulation breakdown of the AC circuit breaker 2. it can.

As described above, in the present embodiment, a three-phase AC power capacitor equipment in which the primary side is connected to the three-phase AC power supply 1, the secondary side is connected in a three-phase star connection, and the neutral point is grounded. In the method and apparatus for switching the load (ON / OFF) of the three-phase AC power supply 3, an AC circuit breaker 2 is provided on the primary side of the three-phase AC power capacitor facility 3 and the secondary side of the three-phase AC power capacitor facility 3 is opened and closed. When the three-phase AC power capacitor equipment 3 is turned off, the switch 4 is tripped and then the AC circuit breaker 2 is tripped.
Eliminate the potential shift at the neutral point with a simple configuration, and when turning off the three-phase AC power capacitor equipment 3, prevent a large voltage from being applied between the poles of the AC circuit breaker 2 due to the potential shift at the neutral point. Accidents such as insulation breakdown of the AC circuit breaker 2 can be prevented.

[0025]

As described above, according to the present invention, when the three-phase AC power capacitor equipment is turned off, the AC circuit breaker is tripped after the switch is tripped. By eliminating the potential shift at the neutral point with the configuration, when turning off the three-phase AC power capacitor equipment, the potential shift at the neutral point prevents a large voltage from being applied between the AC circuit breakers. A method and an apparatus for opening and closing three-phase AC power capacitor equipment that can prevent an accident such as insulation breakdown can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of a method and an apparatus for opening and closing a three-phase AC power capacitor facility according to the present invention.

FIG. 2 is a schematic diagram showing a configuration example of a combination of a conventional three-phase AC power capacitor facility and a switchgear thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Three-phase alternating current power supply 2 ... Circuit breaker 3 ... Capacitor equipment for three-phase alternating current power 4 ... Switch 5: Control device.

Claims (2)

[Claims] 1. A three-phase AC power supply having a primary side connected to a three-phase AC power supply, a secondary side connected to a three-phase star connection, and a neutral point grounded to a three-phase AC power capacitor load switch (ON / OFF).
In the method of performing, the three-phase AC power capacitor equipment provided with an AC circuit breaker on the primary side, and a three-phase AC power capacitor equipment provided with a switch on the secondary side, the three-phase AC power capacitor equipment When turning off
A method for opening and closing a three-phase AC power capacitor facility, wherein the switch is tripped first, and then the AC circuit breaker is tripped. 2. Load switching (ON / OFF) of a three-phase AC power capacitor facility in which a primary side is connected to a three-phase AC power source, a secondary side is connected in a three-phase star connection, and a neutral point is grounded.
An AC circuit breaker provided on a primary side of the three-phase AC power capacitor facility; a switch provided on a secondary side of the three-phase AC power capacitor facility; and Upon receiving an OFF request for the AC power capacitor equipment, a trip command is output to the switch, and a trip command to the AC circuit breaker is provided on condition that the switch is turned off by the trip command. And a control means for controlling the output of the three-phase AC power capacitor equipment.