Features of Operation of High-Voltage Electric Switches

Abstract

The paper draws attention to the fact that nowadays there are many high-voltage switches in operation of different manufacturers and designs, which differ in arc-quenching environment, principle of operation, features of operation. This requires from the maintenance and repair staff additional knowledge and skills agreed with the representatives of enterprises - manufacturers of switches of new designs. Based on the analysis of the statistics of damage to high-altitude switches, it is proved that there is not only damage to obsolete oil or air switches, but also new SF6 switches. the number of damaged SF6 circuit breakers in the total number of damaged high-voltage circuit breakers is 7.1%, while air circuit breakers - 22.3%, and oil circuit breakers - 70.6%. In order to improve the quality of operation of high-voltage switchgear equipment, it is necessary to have information about the technical, preferably current, condition of high-voltage switches. After all, these switches, by disconnecting damaged electrical equipment, significantly reduce the time of leakage of short-circuit overcurrents, and therefore reduce the likelihood of spreading damage to adjacent to the damaged equipment. To reduce errors of the first and second kind when forming conclusions about the technical condition of the diagnosed switch, it is desirable to use modern methods and tools of diagnosis. Conclusions based on the results of diagnosing circuit breakers should take into account the determination of risks during operation of the diagnosed circuit breakers. The following risk components are considered in the article: risk component of damage to living beings as a result of electric shock as a result of non-operation or destruction of the switch; component of the risk of physical damage to high-voltage equipment adjacent to the switch caused by failure of the switch, which could lead to explosion or fire, leakage of SF6 and endanger the environment, component of the risk of failure of internal switch systems due to deterioration main contacts, reduction of SF6 pressure, etc.) during switching on / off of rated currents; components of risk for electrical equipment of the switchgear in case of short circuit near the switchgear, component of risk of failure of internal circuit breaker systems caused by disconnection of short-circuit currents in the cycle of unsuccessful APV; Risk components for switchgear and switchgear equipment in the event of a short circuit in or near switchgear equipment, namely: component of risk of damage to living beings due to electric shock or step voltage during short circuits in switchgear equipment and switch failure , component of risk of physical damage to switchgear equipment (fire or explosion caused by short circuits and overloads of electrical equipment of switchgear and failure of appropriate switches due to unsatisfactory technical condition of the switch; component of risk of failure of the switch caused by damage to the source coil on and off coils, risk components for the circuit breaker during a short circuit in the operating DC line, namely the component of the risk of failure of internal circuit breaker systems caused by breakage or short circuit in the operating DC or voltage lines.