The application of controlled switching device for prevention resonance overvoltages in nonsinusoidal modes

Due to the rising role of overhead lines extra high voltage there is a need of application of modern electronic devices that allow controlling modes of bulk electricity system. The switching control unit Switchsync F236 is one of such devices which enables to connect and disconnect contacts of poles circuit breakers at required time. This function of Switchsync F236 can be used not only for interruption of short circuit. One of the objectives of application Switchsync F236 is prevention of resonance overvoltage occurrence at closing extra high voltage line on no-load autotransformer. Durable resonance overvoltages may cause damage of electrical power equipment. This kind of overvoltages is caused by properties of the network and can be eliminated by changing the values of network parameters. Unlike switching overvoltages that exist centiseconds, resonance overvoltages not only occur unexpectedly, but they may go on for a long time until the automatic action or action of personnel will not change electrical schemes or mode. The resonant overvoltages are neglected when selecting insulation or parameters for high-voltage surge arrester as this protective measure is calculated to limit switching overvoltages, not to extinguish a long resonance process. Therefore, the probability and development of system accidents due to resonance overvoltages is significant. The importance of application and prevention of resonance ovevoltages caused research area which is presented in article.