JPH10304665A - Voltage control equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakdown of a power supply circuit in a control section or a coil of controlling magnet by connecting a three-pole circuit breaker for protecting a voltage control circuit from abnormal current to the primary side of X-phase and Y-phase controlling magnet contactor and a power supply circuit of a control section of a voltage control equipment. SOLUTION: When non-contact switches SSR1x to SSRnx and SSR1Y to SSRny fail in short-circuit mode due to surge noise or the like from the external, if the primary voltage of a transformer TR of the main circuit rises, a tap is disconnected and a tap in one forward step is selected, but an ordinary non-contact switch and a non-contact switch in one forward step are turned on at the same time in the moment when the tap in one forward stage has been selected, an interlayer short circuit of a transformer TR occurs and circuit breaker MCB1 protecting the above is operated. Then, at the same time with the operation of the circuit breaker MCB1, magnet contactors MC1, MC2, MC3 for control and a cable way to the power supply circuit 3 of a control section 2 are also disconnected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention always monitors the primary or secondary voltage of a transformer in a main circuit, and controls the output voltage of the transformer by switching a plurality of taps provided on the transformer with a non-contact switch. The present invention relates to a voltage control device for bringing a voltage applied to a load device connected to a secondary side of a transformer close to a preset reference voltage.

[0002]

2. Description of the Related Art Conventionally, a voltage control device is as shown in FIG. That is, the voltage control device 21 includes a plurality of taps T1x, T2x,
, Tnx have a plurality of taps T1 in the Y phase.
y, T2y, T3y,..., Tny, and these taps are respectively provided with a non-contact switch SSR1.
x, SSR2x, SSR3x, ..., SSRnx, S
SR1y, SSR2y, SSR3y,..., SSRn
and a two-pole circuit breaker MC on the primary side of the contactless switch via a control magnet contactor MC1.
B2 is connected.

The voltage control device 21 includes a transformer T of a main circuit.
The primary or secondary voltage of R is constantly monitored, and the transformer T
The contactless switch is switched under the control of a sequencer (not shown) so that the voltage applied to the load device connected to the secondary side of R approaches the reference voltage preset by the control unit 22.

[0004]

However, when the non-contact switch fails in the short-circuit mode due to external surge noise or the like and the primary voltage of the transformer TR of the main circuit rises, the conventional voltage controller 21 described above Disconnect the tap and select the next higher tap.At the moment the upper tap is selected, the normal tap solid state switch and the higher tap solid state switch are simultaneously turned on. As a result, a short circuit between the phases of the transformer TR occurs, the circuit breaker MCB2 for protecting the short circuit operates, and the primary side of the transformer TR is opened. Then, due to the load current on the secondary side of the transformer TR, the high voltage generated on the primary side of the transformer TR may destroy the coils of the control magnet contactors MC1 and MC2 and the power supply circuit 23 of the control unit 22.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the conventional voltage control device, an object of the present invention is to provide a secondary transformer for a transformer even if a contactless switch fails in a short-circuit mode and a circuit breaker operates. A single-phase voltage control device is provided that can prevent the coil of the control magnet and the power supply circuit of the control unit from being destroyed by the effect of the high voltage generated on the primary side of the transformer due to the load current on the side. The voltage on the primary side or the secondary side of the transformer of the main circuit of the three-wire circuit is constantly monitored, a plurality of taps provided on the transformer are switched by a non-contact switch, and the output voltage of the transformer is controlled. In a voltage control device that brings a voltage applied to a load device connected to a secondary side close to a preset reference voltage, a three-pole circuit breaker for protecting the voltage control device from an abnormal current has an X-phase and a Y-phase. Primary side of the control magnet contactor, and that connected to said power source circuit of the control unit of the voltage controller.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS When a non-contact switch fails in short-circuit mode due to external surge noise or the like, if the primary voltage of the transformer of the main circuit rises, the tap is disconnected.
The upper tap is selected, but at the moment the upper tap is selected, a non-contact switch of a normal tap,
The contactless switch of the upper tap is simultaneously turned on, causing a short circuit between the transformer phases, and the circuit breaker for protecting the short circuit operates. Then, at the same time as the operation of the circuit breaker, the control magnetic contactor and the electric circuit to the power supply circuit of the control unit are also cut off, so the high voltage generated on the primary side of the transformer due to the load current on the secondary side of the transformer causes
It is sent directly without damaging the coil of the control magnet contactor and the power supply circuit of the control unit.

[0007]

FIG. 1 shows a first embodiment of a voltage control apparatus according to the present invention. Hereinafter, the present invention will be described with reference to the drawings.

The voltage control device 1 includes a transformer TR of a main circuit.
Has a plurality of taps T1x, T2x, T3x,.
., Tnx is a plurality of taps T1y, T2y, T
, Tny, are provided respectively, and these taps are provided with non-contact switches SSR1x, SSR2x, SSR, respectively.
SR3x,..., SSRnx, SSR1y, SSR2
, SSRny, a three-pole circuit breaker MCB1 connected to the primary side of a non-contact switch, and an X-phase and Y-phase control magnet contactor MC
1 and the power supply circuit 3 of the control unit 2 of the voltage control device 1.

The voltage control device 1 includes a transformer TR of a main circuit.
Constantly monitors the primary or secondary voltage of the
The non-contact switch is switched under the control of a sequencer (not shown) so that the voltage applied to the load equipment connected to the secondary side of the controller approaches the reference voltage set in advance by the control unit 2.

When the primary side voltage of the transformer TR of the main circuit rises when the non-contact switch fails in the short-circuit mode due to external surge noise or the like, the tap is disconnected and the tap one level higher is selected. At the moment when the upper tap is selected, the contactless switch of the normal tap and the contactless switch of the upper tap are simultaneously turned on, and a short circuit between the phases of the transformer TR occurs to protect the same. The circuit breaker MCB1 operates. Then this circuit breaker MCB
1 and the control magnet contactors MC1,
MC2 and MC3 and the electric circuit to the power supply circuit 3 of the control unit 2 are also cut off, so that the control magnet contactor MC1 is controlled by the high voltage generated on the primary side of the transformer TR by the load current on the secondary side of the transformer TR. , MC2 and the power supply circuit 3 of the control unit 2 are directly sent without being destroyed.

Further, as in a second embodiment shown in FIG. 2, a surge absorber Z is provided at both ends of the primary tap of the transformer TR.
NRx, ZNRy and fuses FUSEx, FUSEy
Is provided, the reliability of interruption of the circuit breaker MCB1 can be improved.

[0012]

As described above, the voltage control apparatus according to the present invention constantly monitors the primary or secondary voltage of the transformer in the main circuit of the single-phase three-wire circuit, and controls the plurality of the plurality of transformers provided in the transformer. A tap is switched by a non-contact switch to control an output voltage of the transformer, and a voltage control device that brings a voltage applied to a load device connected to a secondary side of the transformer close to a preset reference voltage. A three-pole circuit breaker for protecting the voltage control device is connected to the primary side of the X-phase and Y-phase control magnet contactors and to the power supply circuit of the control unit of the voltage control device. If the circuit breaker operates in the short-circuit mode and the circuit breaker operates, the control magnet coil and Can power circuit parts are prevented from being destroyed, there is an effect that it is very safe.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a first embodiment of a voltage control device according to the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the voltage control device according to the present invention.

FIG. 3 is an explanatory diagram of a conventional voltage control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Voltage control device, 2 ... Control part, 3 ... Power supply circuit, TR ... Transformer, T1x, T2x, T3x,
Tnx, T1y, T2y, T3y, Tny ... tap, SSR1x, SSR2x, SSR3x, SSRn
x, SSR1y, SSR2y, SSR3y, SSRny
... Solid state switches, MC1, MC2, MC3 ...
Control magnet contactor.

Claims (1)

[Claims] An output voltage of the transformer is monitored by constantly monitoring a primary or secondary voltage of a transformer of a main circuit of a single-phase three-wire circuit, and switching a plurality of taps provided on the transformer by a non-contact switch. A voltage control device that controls a voltage applied to a load device connected to the secondary side of the transformer to a predetermined reference voltage, and a three-pole circuit cutoff for protecting the voltage control device from abnormal current. A voltage controller connected to a primary side of the X-phase and Y-phase control magnet contactors and a power supply circuit of a control unit of the voltage controller.