JPH0587928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a control signal detection device for power switching equipment used in a power system.

(Conventional technology) Substations are equipped with power switchgear, such as gas-insulated switchgear, that turn on and off high-voltage main circuits.In recent years, efforts have been made to improve the reliability and maintain the power switchgear. There is an increasing demand for a device that automatically monitors the operation of these switching devices for the purpose of reducing the amount of noise and preventing accidents.

As one of the devices that automatically monitors the operation of such power switching equipment, there is a switching time sensor that measures the operating time of the switching equipment. This device detects the current of the closing or tripping command by the current detecting means attached to the closing and tripping control circuit of the power switching equipment, and performs the opening/closing operation by the position detecting means attached to the switching equipment. The output signals of these detection means are input to the measurement means to measure the operating time from the input of the closing or tripping command until the opening/closing operation.

However, the following problems have conventionally existed in detecting closing and tripping commands.

That is, when an output signal of a closing or tripping command is received, it is detected that the closing or tripping command has been input, but it is not possible to determine which command it is. Therefore, the signal from the position detecting means of the opening/closing equipment is input to the discriminating means, and this discriminating means
It is determined whether a switching device is in a closed state or a tripped state, and based on the result, it is determined whether the command is for closing or tripping. That is, a command input when the switching device is in the closed state is determined to be a tripping command, and a command inputted while the switching device is in the tripping state is determined to be a closing command.

However, as described above, providing a separate discriminating means not only complicates the configuration, but also raises the possibility that the operation command cannot be accurately discriminated. That is,
The upper control system in a substation sometimes issues a closing command even though the switching equipment is in the closing state, and sometimes issues a tripping command even though the switching equipment is in the tripped state. be. Therefore, it has been impossible to accurately determine the command from the state of the switching device.

Therefore, in order to solve the above-mentioned problems, although it is not publicly known, the present applicant first installed current detection means and measurement means as shown in FIG. 4 on the closing side and the tripping side, respectively. We proposed a control signal detection device for power switchgear that is installed separately.

That is, FIG. 4 shows a control signal detection circuit for a circuit breaker. It consists of a coil 4a, and a closing coil 4.
The current flowing through a is detected by a through-type current transformer (control current detection means) 5a on the input side. A control wire 6a is wound through the through-type current transformer 5a one or more times to constitute a primary winding of the through-type current transformer. Through-type current transformer 5a on the input side
The output signal is input to a pulse shaping circuit (signal waveform shaping means) 8a via an impedance 7a. Here, the pulse shaping circuit 8a is a receiver that captures the rise of the current I of the input signal and outputs a square wave at a timing that matches the rise, and is configured by, for example, a combination of a Schmitt trigger circuit, a monostable multivibrator circuit, etc. be done.

On the other hand, the tripping circuit is connected to the 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 transmitted through a through-type current transformer (control current detection means) on the tripping side. 5b. A control wire 6b is wound through the through-type current transformer 5b one or more times to constitute a primary winding of the through-type current transformer. 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 matches the rise of the current I. Waves are being output.

In the control signal detection device for electric power switching equipment configured in this way, in the case of a closing operation, when a current I, for example as shown by curve A in FIG. 5, flows through the control circuit in response to a closing command, this The current is detected by the through-type current transformer 5a on the closing side. As a result,
The output signal of the feed-through current transformer 5a on the input side is input to a pulse shaping circuit 8a, and the pulse shaping circuit 8a outputs a pulse as shown by curve B in FIG.

By the way, the peak value, di/dt, etc. of the current I are as follows:
Since it is determined by the impedances 3 and 10 that are connected in series or parallel with the closing and tripping coils 4a and 4b, it depends on the model of the circuit breaker, and even if the circuit breaker is the same model, whether it is a closing circuit or a breaking circuit. They differ greatly.

On the other hand, the output from the receiver is not at the rising edge of the current I, but at a set value determined by the circuit constants of the receiver. That is, when the peak value of the current I reaches the set value, it is output as a one-shot pulse. For this reason, the wave height value
When detecting a small current di/dt, as shown in FIG. 5, the output is delayed by a time _t1 from the rise of the voltage I. Sensor 1 and sensor 2
are sensors that indicate the operating position of the main shaft of the opening/closing device; for example, sensor 1 is placed in the closing position, and sensor 2 is placed in the closing position.

Normally, the opening/closing time is measured by the time T from the rise of the control current to the output of sensor 1, as shown in Figure 5. If the delay time _t1 is large, accurate measurement cannot be performed, and the switching equipment This was not desirable as a device for automatically monitoring operations.

(Problems to be Solved by the Invention) As mentioned above, in the conventional control current detection device for power switchgear, when the peak value or di/dt of the current flowing through the control circuit is small, the rise of the control current , a large delay may occur between the time output from the detector and the time output by the detector, making it impossible to perform accurate measurements.

The present invention was proposed in order to solve the problems of the prior art, and its purpose is to provide control that can obtain an output almost simultaneously with the rise of the control current and that does not adversely affect the receiver. An object of the present invention is to provide a current detection device.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a position detecting means attached to a power switchgear, and a position detecting means for turning on/off the power switchgear. Control of a power switchgear, comprising: a current detection means attached to a control circuit; and a measurement means for measuring the operation time of the power switchgear from the output signal of the current detection means and the output signal of the position detection means. In the signal detection device, the current detection means includes a feedthrough current transformer disposed in the closing and tripping control circuit, and a primary winding of the feedthrough current transformer is connected to the closing and tripping control circuit. The number of turns of the control line of this feedthrough current transformer is a value that compensates for the delay time from the rise of the control current flowing through the control circuit to the output of the current detection means. It is characterized by being set to .

(Function) According to the present invention having the above configuration, the number of turns of the control wire of the feedthrough current transformer is determined based on the control current flowing through the control circuit, taking into consideration the peak value and di/dt of the control current. Since the value is set to compensate for the delay time from the rise of the control current to the output of the current detection means, the output can be obtained almost simultaneously with the rise of the control current, minimizing the delay time and ensuring accurate measurement. It becomes possible.

(Example) The number of turns of the control winding when the control current detection device for power switching equipment according to the present invention as explained above is applied to the signal detection circuit of the circuit breaker shown in FIG. This will be explained in detail based on FIG.

In this example, the number of turns n of the control wire to the feedthrough current transformer used in switching equipment such as circuit breakers is
An appropriate number of turns is set on each of the closing and closing sides based on the peak value and di/dt of the control current.

Further, the number of turns on the input side is set to be three times or more the number of turns on the disconnection side.

In other words, the number of turns n of the control wire to the feed-through current transformer and the delay time t ₁ are inversely proportional as shown in Figure 1, and the number of turns n of the control wire to the feed-through current transformer is inversely proportional to As the number n increases, the output signal of the current transformer becomes larger, so the upper limit of the number of turns is determined by the receiver's withstand voltage performance. The number n can be set appropriately.

Furthermore, as shown in Figure 2, when comparing the measured value A of the control current waveform on the cutoff command side and the measured value B of the control current waveform on the make command side, the peak value of the control current on the make command side is Approximately 1/ compared to the peak value on the cutoff command side
3, therefore, by making the number of turns of the control line to the through-type current transformer on the closing side approximately three times or more than the number of turns on the closing side, the respective delay times t ₁ can be made equal.

In this way, by setting the appropriate number of turns of the control line to the feed-through current transformer and changing the number of turns on the cut-off side and the make-on side, the delay time _t1 can be minimized and the control The output can be obtained almost simultaneously with the rise of the current, and the influence on the receiver can be reduced, making it possible to standardize feedthrough current transformers and receivers.

Note that the present invention is not limited to the circuit breaker shown in FIG. 4, but can be applied to various switching devices. As an example, a control signal detection device for a circuit breaker is shown in FIG.

That is, 13 is an input terminal for the circuit breaker on/off command;
14 is a switch for direct or remote operation.
When a command is input to the input terminal 13, the closing coil 15a (or tripping coil 15b) is excited, the contact 16a (or 16b) is closed, and the motor 1
A current flows through 7. 5 is a through-type current transformer for detecting this current, and a control line 18 passes through this current transformer.
Further, an impedance 7 is connected to the through-type current transformer 5, and a signal from the current transformer 5 is sent to a receiver 8, and after waveform shaping, is output as a square wave.

Normally, in a disconnector, the peak value and di/dt of the motor current are very large (about 3 to 10 times) compared to the peak value and di/dt of the circuit breaker, and the control to the feedthrough current transformer 5 is Even if the number of turns of the wire is one, sufficient detection is possible.

[Effects of the Invention] As explained above, according to the present invention, the number of turns of the control line around the feedthrough current transformer is determined by adjusting the peak value of the control current and the number of turns of the control line around the feedthrough current transformer.
By simply setting the appropriate number of turns using di/dt and changing the number of turns of the control line on the cut-off side and the make-on side, an output can be obtained almost simultaneously with the rise of the control current, and the receiver It is possible to provide a control current detection device that does not adversely affect.

[Brief explanation of the drawing]

Fig. 1 shows the relationship between the number of turns n of the control line and the delay time _t1 in the control signal detection device of the present invention, and Fig. 2 shows the relationship between the control signal detection circuit of a circuit breaker when the present invention is applied. 3 is a circuit diagram showing another embodiment of the present invention, and FIG. 4 is a circuit breaker control signal detection circuit. Circuit diagram showing 5th
The figure is a time chart showing the command current, the pulse shaping circuit, and the output signals of each position detection means. 1... Closing command input terminal, 2... Changeover switch, 3, 7a, 7b, 10... Impedance,
4a... Closing coil, 4b... Tripping coil, 5
a... Through-type current transformer on the closing side (control current detection means on the closing side), 5b... Through-hole current transformer on the tripping side (control current detection means on the tripping side), 6a... Closing-side control line, 6b... tripping side control line, 8a... pulse shaping circuit on the closing side (signal waveform shaping means on the closing side), 8b... pulse shaping circuit on the tripping side (signal waveform shaping means on the tripping side) , 9... Tripping command input terminal, 13... On/off command input terminal, 14... Changeover switch, 15a... Closing coil, 15b...
Tripping coil, 16... Contact, 17... Motor,
18...Control line.

Claims (1)

[Scope of Claims] 1. A position detection means attached to a power switchgear, a current detection means attached to a closing/tripping control circuit of the power switchgear, and an output signal of the current detection means and the In a control signal detection device for a power switchgear device, the control signal detection device includes a measuring means for measuring the operation time of the power switchgear device from an output signal of the position detection means, wherein the current detection means is arranged in the closing and tripping control circuit. The primary winding of this through-type current transformer is constituted by the control wire of the closing and tripping control circuit, and the winding of the control wire of this through-type current transformer is A control signal detection device for power switching equipment, characterized in that the number is set to a value that compensates for a delay time from the rise of the control current flowing through the control circuit to the output of the current detection means. 2. The control circuit includes a closing-side control circuit and a cut-off control circuit, and each of the closing-side control circuit and the cut-off control circuit is provided with a feed-through current transformer whose primary winding is the control line of each control circuit. The number of turns of the control line of the feed-through current transformer attached to the closing-side control circuit is equal to the number of turns of the control line of the feed-through current transformer attached to the breaking-side control circuit. The control signal device for power switching equipment according to claim 1, characterized in that the number of signals is greater than the number of signals. 3. A patent claim in which the power switchgear is a circuit breaker, and the number of turns of the control line in the closing-side control circuit is three times or more the number of turns of the control line in the closing-side control circuit. A control signal detection device for power switching equipment according to scope 2.