Discussion on on-line detection of the hottest vac

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Discussion on the detection of vacuum circuit breaker

1 the development trend and existing problems of vacuum circuit breaker

the advantages of vacuum circuit breaker are not only oil-free equipment, but also in that it has a long electrical life, mechanical life, large breaking insulation capacity, strong continuous breaking capacity and strong stability. The deformation measuring instrument is one of the factors worth considering by users. 1. Small volume, light weight, frequent operation, fire prevention With the advantages of less operation and maintenance and low failure rate, it is an ideal electrical equipment for unattended substation. At present, it is widely developed and used at home and abroad, and has the trend of completely replacing oil arc extinguishing medium. At present, multi-functional microcomputer (Electronic) protection devices are mostly used in substations, and the degree of comprehensive automation is also improved. The requirement of tending to be unattended has been basically met. Therefore, the main electrical equipment is required to have a certain detection (self-test) function, and the vacuum circuit breaker should not be an exception. The common faults of vacuum circuit breakers are mainly manifested in two parts:

(1) mechanical faults. Since the probability of such failure rate is smaller than that of electrical failure rate, the implementation of detection still requires the relevant departments to further improve the unified plan of enterprise concentration in terms of structure, size and combination mode

(2) electrical fault. This kind of fault is the main problem that directly threatens the safe, lasting and stable operation of electricity, and its probability cannot be ignored. Compared with mechanical fault, an electrical fault of vacuum circuit breaker is not only serious in nature, but also hidden, sudden, random, and difficult to predict in time. Therefore, manufacturers often remind users to observe the physical phenomenon of arc breaking in the vacuum interrupter in the factory report. Therefore, this kind of fault not only threatens the safety of electricity, but also easily causes personal and national economic losses

2 detection methods for solving vacuum circuit breakers

at present, there are many detection methods for vacuum circuit breakers, including the following common ones: ① capacitance induction method; ② Artificial neutral point method; ③ High voltage electric field induction method; ④ Resistance capacitance partial pressure method; ⑤ Photoelectric remote sensing method

in addition, there is a measurement method of vacuum circuit breaker based on Penning discharge principle (electromagnetic wind)

to sum up, each has its own characteristics. Although they can also obtain the signal that the breaking capacity of the vacuum circuit breaker is reduced due to air leakage in the vacuum arc extinguishing chamber under specific circumstances, they can achieve the purpose of alarm and locking after electrochemical processing. There are still many problems to be discussed if we want to promote and use it comprehensively

in terms of the method of artificial neutral point method (see Figure 1), C and R in the figure use high-voltage capacitors or high-value resistors to form artificial neutral points. Although the overall circuit resistance (reactance) value is or is large (when using high-voltage capacitors, the capacitive reactance is large), it does not have much impact on the whole system under normal working conditions. It is reasonable and characteristic to use high voltage potential and n (grounding) point reference to detect whether the vacuum circuit breaker is in good condition. If such methods are widely used, and some vacuum circuit breakers are overhauled or faulty, it is obvious that they are a virtual grounding point formed between the main system and the ground. Therefore, the organization scheme of safety work, relay protection setting calculation and operation configuration cannot be ignored. As for other schemes, there are also some problems, such as large volume, complex structure, no use of external energy, poor anti-interference, low seismic capacity, difficult remote transmission of data, and only effective for glass shell or easy to observe vacuum circuit breakers. Therefore, the actual impact and feasibility should be carefully considered when these methods are popularized and actually adopted

in fact, the detection of vacuum circuit breaker can also be achieved by other methods, and it is not very complicated. The interest of this subject is to measure the negative pressure change of vacuum interrupter. Its key point is that the detection device itself should not only have better electrical insulation capacity and smaller, add appropriate hydraulic oil in the chassis to reduce the volume of insufficient power and reliable operation performance, but also try to have safety specifications, reasonable standards, convenient use, minimum maintenance and stable cycle. In addition, it should also have the dual functions of data remote transmission and local notification, and the communication should also have standard transmission characteristics, which should not be different from relay protection

in order to do a good job in the detection of the arc extinguishing chamber of vacuum circuit breaker, it must comply with the current electric operation mechanism and feedback requirements, otherwise the consensual result can only solve a local problem and bring some unnecessary repetitive work or burden

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