Application of multi-level spark gaps in resonant-type fault current limiter

With the rapid development of power industry, power load is also rising, leading to increased levels of short-circuit current, so the demand of the technology of short-circuit current limit is very urgent. Resonant-type fault current limiter used in extra high voltage(EHV) power grid makes high-power electronic devices with a slow response, limited withstand short-circuit current limited ability and cost disadvantages as trigger system. A new kind of multi-level spark gaps connected with frequency-dependent network, with high reliability, fast response and low cost advantages is made, which can effectively replace the highpower electronic devices to trigger resonant-type fault current limiter. In this paper, a new kind of smart passive trigger system for resonant-type fault current limiter is made. This new kind of smart passive trigger system mainly contains a series of multilevel spark gaps, a Tesla transformer, an isolation transformer and a Rogowski coil. The trigger system can identify the short-circuit fault automatically and make the Tesla transformer produce high-frequency high-voltage pulse to breakdown multilevel spark gaps to trigger resonant-type fault current limiter. The trigger system doesn't require on-line detection, control system and external power. It has advantages of high reliability, high response speed and low cost.