JPH0384481A - Monitoring device for withstand voltage between poles of vacuum circuit breaker for condenser bank - Google Patents

Abstract

PURPOSE:To obtain a withstand voltage performance of a vacuum circuit breaker by providing a measuring means for detecting a preceding discharge thrown at a pole closing operation and measuring the distance between poles. CONSTITUTION:A start for throwing operation of the circuit breaker 3 is detected by a rotary encoder 4. An operation angle of operating shaft is obtained from the pulse output generated from the rotary encoder 4. The beginning of a preceding discharge current made to flow is detected by a signal ILED from an optical fiber 14 and the distance ls between poles is calculated by the rotary encoder 4. The output E of a differential amplifier 10 at that time becomes an impressing voltage Es between poles. The withstand voltage between poles is obtained by a data processing circuit 15 based on the impressed voltage Es between poles at the time point when the preceding discharge current is begun to flow and the distance ls between poles. This withstand voltage between poles is compared with the reference withstand voltage characteristic between poles which is being stored inside beforehand, and also the change of this compared value is trend-processed, then a deterioration of the withstand voltage between poles is diagnosed to issue an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a withstand voltage monitoring device between contacts of a vacuum circuit breaker for a capacitor bank.

89 Summary of the Invention The device for monitoring withstand voltage between contacts of a vacuum circuit breaker for a capacitor bank of the present invention measures the distance between the electrodes from the movement of the circuit breaker during closing operation, and detects the voltage on the power supply side of the vacuum circuit breaker and the voltage on the capacitor bank side. The voltage applied between the electrodes is measured from the current on the capacitor bank side, the start of the pre-discharge current is detected, and the withstand voltage performance between the electrodes is monitored in the operating state from the applied voltage between the electrodes and the distance between the electrodes at the time when the pre-discharge current starts to flow. It is made to be moisturized.

C1 Conventional technology Vacuum circuit breakers do not require maintenance of contacts, so they are widely used in power substations,
It is used as a power distribution circuit breaker. Among these, the interelectrode withstand voltage of the circuit breaker used in the power factor adjustment capacitor bank becomes extremely important in terms of preventing restriking.

This reduction in withstand voltage performance between the electrodes varies greatly depending on the electrical conditions used, such as the closing and shutting conditions.

Conventionally, vacuum circuit breakers have been maintained by measuring the degree of vacuum, integrated value of breaking current, etc. while the circuit breaker is in operation, but now it is necessary to monitor the deterioration of the withstand voltage performance between the electrodes during operation. There was no way.

D3 Problems to be Solved by the Invention For this reason, it has not been possible to appropriately prevent restriking of circuit breakers used in conventional capacitor banks.

The present invention has been made in view of these problems, and its purpose is to provide a vacuum circuit breaker for capacitor banks that can monitor the withstand voltage performance between the electrodes of the vacuum circuit breaker for capacitor banks in an operating state. An object of the present invention is to provide a withstand voltage monitoring device between contacts of a vacuum circuit breaker.

82 Means for Solving the Problems In order to achieve the above object, the vacuum circuit breaker for a capacitor bank according to the present invention has an inter-electrode distance measurement method that measures the inter-electrode distance by detecting the movement of the interrupting part during the closing operation. means for measuring the voltage applied between the electrodes for detecting the voltage on the power supply side and the voltage on the capacitor bank side and measuring the difference between the two voltages; and means for detecting the beginning of flow of the preceding discharge current for detecting the beginning of the flow of the current on the capacitor bank side; The data processing means receives the output of each means and calculates the withstand voltage performance between the electrodes from the voltage applied between the electrodes and the distance between the electrodes at the time when the start of flow of the preceding discharge current is detected.

Since the distance between the electrodes when the 11 action is interrupted is known, the distance between the electrodes can be measured by detecting the movement of the interrupter during the closing operation.

If the voltage applied between the electrodes is measured from the voltage on the power supply side and the voltage on the capacitor bank side, the voltage applied between the electrodes can be measured via a transformer or the like.

By detecting the beginning of the flow of current on the capacitor bank side, the beginning of the flow of the preceding discharge current, that is, the beginning of flashover, can be determined.

Therefore, the withstand voltage performance of the circuit breaker can be determined from the voltage applied between the electrodes and the distance between the electrodes at the time when the preceding discharge current begins to flow.

Therefore, the data processing means determines the inter-electrode withstand voltage, or compares the inter-electrode withstand voltage value with the reference inter-electrode withstand voltage characteristic, and processes the change in the value as a trend. Deterioration of voltage can be determined.

G. Example Embodiments of the present invention will be described with reference to the drawings.

Figure 1 shows the circuit configuration of a vacuum circuit breaker contact breakdown voltage monitoring device for capacitor banks. In Figure 1, 1 is the main circuit, 2 is the capacitor bank connected to the main circuit l, and 3
is a vacuum breaker inserted into the main circuit l, 4 is a rotary encoder installed on the operating shaft linked to the breaker to measure the opening/closing operation of the vacuum breaker, and 5 is the rotation direction based on the pulse output generated by the rotary encoder. 6 is a touch point value setter that outputs a preset value of the touch point of the cutoff section; 7 is a counter that sets the count value of the counter 5 and the touch point value setter 6; A digital comparator that compares the count value and outputs a touch point signal S when the count value reaches the touch point.

8 is a voltage transformer that detects the voltage V1 on the power supply side, 9 is a voltage divider that detects the voltage V on the capacitor bank 2 side, 10 is a differential amplifier that outputs the difference voltage E between the voltages V+ and Vt, 11
1 is a current transformer that detects the current on the side of capacitor bank 2; 12 is a small auxiliary current transformer that detects the secondary current of current transformer 11;
3 is a current flow start detection circuit that causes a light emitting diode to emit light using the secondary energy of the current transformer 12; 14 is an optical fiber that transmits the light emitting signals L, D of the light emitting diode; 15 is a digital comparator 7; a differential amplifier 10. This is a data processing circuit to which signals E, S, and ILto from the optical fiber 14 are input.

Next, the operation of this monitoring device will be explained with reference to the time chart of FIG.

The rotary encoder 4 detects the start of the closing operation of the circuit breaker 3. The operating angle of the operating shaft is determined from the pulse output generated by the rotary encoder 4. The beginning of the flow of the preceding discharge current is detected by the signal I LED from the optical fiber 14, and the inter-electrode distance e8 is calculated by the rotary encoder 4. Also, the output E of the differential amplifier 10 at that time becomes the inter-electrode applied voltage E5.

The voltage applied between the main circuit contacts of the circuit breaker is determined by voltage transformers arranged for each phase. However, the time from the beginning of the flow of the preceding discharge current to the touch point t s h < 1
Calculate only when the pressure is greater than m s (if the input speed is 1 m/sec, ts = 1 ms is the interelectrode pressure MIRm, and jaz
The fact that the pre-discharge current begins to flow when the voltage is below z indicates that the inter-electrode withstand voltage characteristics are good).

The data processing circuit 15 determines the withstand voltage between the electrodes based on the inter-electrode applied voltage Es and the inter-electrode distance 12s at the time when the preceding discharge current starts flowing. In addition, this interelectrode withstand voltage is compared with the standard interelectrode withstand voltage characteristics stored internally in advance, and trend processing is performed on changes in the value to diagnose deterioration of the interelectrode withstand voltage and issue an alarm. It is designed to emit.

H1 Effects of the Invention Since the present invention is configured as described above, it produces the following effects.

■It is possible to detect the preceding discharge during the closing operation and determine the withstand voltage performance of the vacuum circuit breaker from the voltage applied between the electrodes and the distance between the electrodes at that time.

(2) The interelectrode withstand voltage characteristics are determined for each closing operation, and changes in operating conditions can be investigated.

■Since it is possible to diagnose the deterioration of the interelectrode withstand voltage and issue an alarm, it is possible to prevent the re-ignition of vacuum circuit breakers used in capacitor banks.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2(a) -
(c) and (d) are time charts showing changes in each signal and the distance between electrodes in the same circuit, and FIG. 3 is a flow chart of measurement processing in the same circuit. ■...Main circuit 1.2...Capacitor bank, 3...
・Vacuum circuit breaker, 4...Rotary encoder, 5...
- Counter, 6... Touch point value setter, 7... Digital comparator, 9... Voltage divider, 10... Differential amplifier, 13... Current flow start detection circuit, 15...
・Data processing circuit. Pre-discharge current begins to flow

Claims (1)

[Claims] (1) Interelectrode distance measuring means that measures the distance between the electrodes by detecting the movement of the interrupting part during the closing operation, and an interelectrode distance measuring means that detects the voltage on the power supply side and the voltage on the capacitor bank side and measures the difference between the two voltages. Applied voltage measuring means; Pre-discharge current flow start detection means for detecting the start of flow of current on the capacitor bank side; Outputs of the respective means are input, and voltage applied between the electrodes at the time when the start of flow of the pre-discharge current is detected. and data processing means for calculating the inter-electrode withstand voltage performance of the circuit breaker from the inter-electrode distance.