Повышение пропускной способности ограничителей перенапряжений в составе вакуумных выключателей постоянного тока

Abstract

One of the problems that must be solved when short-circuit currents breakdown in a DC vacuum circuit breaker is the dissipation of electromagnetic energy stored in the inductance of the Lc network and brought by the source at the time of the current breakdown, as well as limiting the overvoltages on the circuit breaker elements. The high level of overvoltages U»Lсdi/dt is due to the rapid fall of the di/dt trip current in the network with inductance Lc, which, for example, in traction networks of electrified rail transport reaches 15 mH. To solve this problem, a nonlinear overvoltage arrestors (NOA) is used, which is installed parallel to the circuit breaker and provides for the overvoltage limiting and also serves to absorb electromagnetic energy stored in the inductance of the network. The amount of absorbed energy should not exceed the amount of energy dissipated into the outer space. Otherwise, there will be a constant increase in the temperature of the arrester and its subsequent thermal destruction. The energy absorbed in the arrester unit when the current is breakdown (Ibr2Lc/2) depends on the breakdown current Ibr and the inductance of the network Lc. The energy dissipated depends on the design of the arrester unit and the mass of the supply tires. The balance between absorbed and dissipated energy determines the throughput of the arrester unit without degrading it. The throughput of surge arresters with high current pulses is determined by its ability to withstand the max supply tires. The balance between absorbed and dissipated energy determines the throughput of the arrester unit without degrading it. The throughput of surge arresters with high current pulses is determined by its ability to withstand the maximum value of current pulses with duration of several milliseconds. This paper presents the results of numerical simulation and experimental research of ways to increase the throughput of an oxide-zinc (ZnO) surge arrester as part of a DC vacuum circuit breaker.