JPH01292716A - Control signal detecting device of power breaker - Google Patents

Abstract

PURPOSE:To prevent an error operation of ripple generated in a control unit by providing a penetration type current transformer to detect the control current for tripping at the tripping coil side from the connection of a trip circuit and a sealing-in circuit. CONSTITUTION:A penetrating type current transformer 5b to be a control current detecting device is provided at a tripping coil 46 side from the connection 21 of a trip circuit 9 and a sealing-in circuit 20. Therefore, at the former phase the breaking instruction of a breaker is input to an input terminal 9, the current I0 flowing from the sealing-in circuit 20 flows in to the next phase regardless of the penetration type current transformer 5b. As a result, the penetration type current transformer 5b does not detect the current I0 of the sealing-in circuit 20, but detects only the regular tripping instruation current I. The control signal can be detected with no error measurement, consequently.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a control signal detection device for a power circuit breaker used in a circuit breaker operating time measuring device.

(Conventional technology) Substations are equipped with power circuit breakers that perform important operations in high-voltage main circuits such as gas-insulated switchgear.In recent years, efforts have been made to improve the reliability and maintenance of these power circuit breakers. There is an increasing demand for a device that automatically monitors the operation of these circuit breakers for the purpose of reducing the number of accidents and preventing accidents.

As one of the devices that automatically monitors the operation of such a power circuit breaker, there is a switching time sensor that measures the operation time of the circuit breaker. This operation is performed by detecting the current of the closing or tripping command by the current detecting means attached to the closing and tripping control circuit of the power circuit breaker, and by detecting the opening/closing operation by the position detecting means attached to the switching equipment. By inputting the output signal of the detection means to the measurement means, the operating time from the input of the closing or tripping command to the opening/closing operation is measured.

As a method for detecting such a circuit breaker operating command, the following method has been proposed in Japanese Patent Application No. 62-062501@. That is, FIG. 2 shows the circuit breaker control signal detection circuit, and the closing circuit is connected to closing command input terminal 1.
It is composed of a changeover switch 2, an impedance 3, and a closing coil 4a provided in parallel with the impedance 3, and the current flowing through the closing coil 4a is determined by a current transformer (control current detection means) on the closing side. 5a.

A control line 6a passes through the through-type current transformer 5a at least once. The output signal of the feed-through current transformer 5a on the input side is:
The signal is inputted to a pulse shaping circuit (signal waveform shaping means) 8a via an impedance 7a. Here, pulse shaping circuit 8
A is a receiver that captures the rising edge of the input signal and outputs a square wave at a timing that matches the rising edge of the current, and is composed of a combination of, for example, a Schmitt trigger circuit or a monostable multivibrator circuit.

On the other hand, the tripping circuit is composed of a tripping command input terminal 9, an impedance 10, and a tripping coil 4b provided in series with the impedance 10, and the current flowing through the tripping coil 4b is on the tripping side. Through-type current transformer (
The control current is detected by the control current detection means>5b. A control line 6b passes through the through-type current transformer 5b at least once. The output signal of the feedthrough current transformer 5b on the tripping side is input to a pulse shaping circuit (signal waveform shaping means) 8b via an impedance 7b, and similarly to the input side, it is converted into a square shape at a timing that coincides with the rise of the current ■. Waves are now output.

In the control signal detection device for a power circuit breaker configured as described above, in the case of a disconnection operation, when a current flows through the control circuit in response to a disconnection command, this current is interrupted. It is detected by the through-type current transformer 5b on the side. As a result, the output signal of the cut-off side feedthrough current transformer 5b is input to the pulse shaping circuit 8b, and the pulse shaping circuit 8b outputs a pulse as shown by curve B in FIG. The time delay tl from the rise of the control current to the output of the detector output pulse is normally set to within 1 ms.

On the other hand, the circuit breaker operating position detection sensor detects each position of the closed and tripped states, and outputs a square wave like the C2D curve in FIG. 3. In this way, the operation of the device can be monitored by measuring the time T1 shown in FIG. 4 until each position detection sensor output pulse, based on the detector output pulse.

(Problems to be Solved by the Invention) Such a system has the following drawbacks. In other words,
When the device is operating, before the original command signal flows through the control circuit, ripples may occur in the control current A as shown in Figure 4 due to the influence of other relay operations included in the control circuit or wrap-around within the control circuit. may occur.

Ripples that occur due to the effects of normal relay operation, etc.
These effects are small in terms of level, and by adjusting the sensitivity at the input section of the pulse shaping circuit 8b, it is possible to eliminate these effects without significantly affecting the characteristics of the control signal detection device. However, in the breaker exception circuit, the feed-through current transformer 5b on the tripping side is installed after the tripping circuit 9 and the seal-in circuit 20 merge, so as for the leakage from the seal-in circuit 20, For the purpose of a protective relay trip, several tens of mA of relay excitation current may flow from the seal-in filter 20 before the normal cutoff signal current (2) flows. Therefore, a ripple IO, which is much larger than other ripples, flows into the control line where the detection feedthrough current transformer (control current detection means) 5b is installed before the normal control current signal rises. .

The control current detection circuit captures the rising edge of the tuple (I) as described above and outputs a pulse. For this reason, the operating time To of the device is equivalently extended, and there is a problem that false alarms, such as when the operating time is exceeded, occur.

An object of the present invention is to provide a control signal detection device for a power circuit breaker that can accurately measure operating time without malfunctioning due to ripples generated in the control current.

[Structure of the Invention] (Means for Solving the Problems) Control of a power circuit breaker according to the present invention! ! The signal detection device is
The present invention is characterized in that the control current detection means is provided closer to the tripping coil than the normally used connection point between the tripping circuit and the seal-in circuit.

(Function) In the present invention, large ripples generated in the control current from the seal-in circuit can be excluded, and the operating time of the circuit breaker can be accurately measured.

(Example) The present invention will be explained below with reference to the embodiment shown in FIG.

In FIG. 1, the same reference numerals as in FIG. 2 indicate the same parts, so the explanation thereof will be omitted.

In FIG. 1, the control signal detection device for a power circuit breaker according to the present invention detects a trip coil current transformer 5b as a control current detection means from a connection point 21 between a trip circuit 9 and a seal-in circuit 20. It is characterized by being provided on the 46 side.

In FIG. 1, before the circuit breaker interrupting command enters the input terminal 9, the current ■o flowing from the seal-in circuit 20 is:
It flows into the next stage regardless of the oil-through current transformer 5b on the tripping side. Therefore, the oil-through current transformer 5b does not detect the current IO of the seal-in circuit 20, and the normal trip command current
will be detected only. There is no problem even if the oil-through current transformer 5b is provided on the tripping coil side, and the operating time can be detected with sufficient accuracy.

[Effects of the Invention] As explained above, according to the present invention, an accurate power circuit breaker without erroneous measurements can be achieved by changing the installation location of the oil-through current transformer of the control current detection means. A control signal detection device can be configured.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of a control signal detection device for a power circuit breaker according to the present invention, FIG. 2 is a circuit diagram showing a conventional control signal detection circuit for a circuit breaker, and FIGS. 3 and 4 1 is a time chart diagram showing output signals of a control current, a control signal detector, and a position detection sensor; FIG. 1... Closing command input terminal 2... Changeover switch 3.7a, 7b, 10... Impedance 4a...
Closing coil 4b...Tripping coil 5a...Through oil current transformer 5b on the closing side...Through oil current transformer 8a on the tripping side...Pulse shaping circuit 8b on the closing side...Tripping Side pulse shaping circuit 9...Tripping command input terminal 20...Seal-in circuit 21...Connection point ■...Tripping command current IQ...Current flowing from the seal-in circuit (ripple) (8733 ) Agent Patent Attorney Yoshiaki Inomata (Baka
1 person) b Figure 1

Claims (1)

[Claims] In the closing and tripping control circuit of a power circuit breaker equipped with a closing circuit, a tripping circuit, and a seal-in circuit, a feed-through current transformer for detecting the tripping control current is connected to the tripping circuit and the seal-in circuit. A control signal detection device for a power circuit breaker, characterized in that it is provided on the tripping coil side from the point.