On-line monitoring methods for high-voltage circuit-breaker switching on-off time

Abstract

The present invention relates to a method of monitoring the gate opening and closing time on line by a high-voltage circuit breaker. The inception time for the breaker gate opening and closing coil with electricity can be obtained through the voltage telecommand sampling of the breaker gate opening and closing coil, the time for the separation and connection of breaker head can be obtained through three-phase voltage telecommand sampling of capacitance sensor of high-voltage electricity-carrying display device that is arranged on the electric power transmission lines. The time gap between the inception time of breaker gat closing coil with electricity and the finish time of separation of breaker head is calculated, then the gate opening time is worked out; the time gap between the inception time of breaker gate closing coil with electricity and the finish time of jointing of breaker head is calculated, then the gate closing time is worked out. The method of the present invention bases on the telecommand sampling of voltage signal; brings the operating facilities of electric power system into full play; and overcomes the shortcomings of previous online monitoring methods; thereby making the verification of time point more conveniently and accurately, and reducing the cost, thus being favorable for the realization of state repairing of the breaker.

Description

technical field [0001] The invention relates to an on-line monitoring method for a high-voltage circuit breaker, in particular to an on-line monitoring method for the opening and closing time of a high-voltage circuit breaker. Background technique [0002] Among the devices in the power system, the high-voltage circuit breakers have the largest number, a large amount of maintenance, and high costs. Relevant statistics show that more than half of substation maintenance costs are spent on high-voltage circuit breakers, and 60% of them are used for minor repairs and routine maintenance of circuit breakers. In the past, planned maintenance based on cycle (time) was carried out. According to statistics, 10% of circuit breaker failures are caused by incorrect maintenance. The circuit breaker must be completely disassembled during the overhaul, which is time-consuming and expensive. Disassembly and reassembly can introduce many new defects. In order to improve the pertinence of m...

AI Technical Summary

Problems solved by technology

This method has the following disadvantages: 1: The current of the opening / closing coil of the circuit breaker itself is an object of on-line monitoring of the circuit breaker, and the magnitude and duration of the opening / closing coil current reflect the mechanical operation of the circuit breaker The quality of the mechanism reflects the advantages and disadvantages of the mechanical characteristics of the circuit breaker. Once the performance of the operating mechanism is poor, it will directly affect the current of the opening / closing coil of the circuit breaker; 2: The resistance of the opening / closing coil of different circuit breakers It is different from reactance, and the current of the corresponding opening / closing coil will also be different; 3: Different R-L parameters of different coils affect the steepness of current rise, and it is difficult to set the threshold or threshold value of "current or no current" 4: The opening / closing coil current of the circuit breaker has a changing process, and different threshold values ​​will correspond to different time points. Therefore, different threshold value settings will produce Different starting moments of the closing process; 5: The fault of the circuit breaker (including the fault of the operating mechanism) will cause the change of the coil current

In fact, when closing, when the moving contact of the circuit breaker has not reached the closing position point, the main circuit has already passed the pre-breakdown current, so the presence or absence of current cannot correctly reflect the actual closing of the contact of the circuit breaker time

This method also has the following defects: first, there must be a load current, once there is no load in the operation process, the existence of the current cannot be monitored, and the location cannot be located; second, the threshold value for judging the existence of the current The size affects the accuracy of the opening / closing completion time of the circuit breaker contacts; thirdly, a current transformer must be installed in the online monitoring device. If it is used together with the current transformer existing in the original system, the damage of the monitoring device is likely to affect the use The performance of other devices of the current transformer, which is contrary to the principle that the added monitoring device cannot destroy the performance of the original device

Since the auxiliary switch is a mechanical contact switch, the conversion speed is poor and unstable, so the measurement results are biased; what's more, the auxiliary contact of the circuit breaker is also one of the parameters of the circuit breaker's online monitoring

[0016] In short, the existing on-line detection methods for the opening and closing time of high-voltage circuit breakers have their own shortcomings, such as high practical application cost, poor accuracy, and unsatisfactory results.

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