Economic Fault Current Limiter

Along with the scale of our national electric power net expanding rapidly, the electric power loads rising swiftly and big capability units going into function, the short circuit level is increasing day after day. How to limit the short circuit current became an important technical task of the development in electric power net. Therefore Fault Current Limiter (FCL) became the most popular research subject.Various of FCL are present in this article. Considering the feasibility and economy, Superconducting Fault Current Limiter (SFCL) and Flexible Short Current Limiter (FSCL) are difficult to apply in electric power net in the near future. Economical FCL based on general electric equipments which are un-superconducting or un-electronic is undoubtedly the best choice to solve the questions of limiting fault current. An optimized configuration about the series resonant FCL based on ZnO arrester is put forward in this article. Also, the 10W voltage sample in laboratory has been developed. Depending on simulant running experiment, the dynamic characteristic has been checked and the feasibility has been validated. These are the bases of 110kV and higher voltage rank FCL.To investigate the mutual influences between FCL and power net is the precondition of FCL which will achieve project application, including the mutual influence between FCL and the whole system involving various pivotal electric equipments. This article thoroughly simulated the influence of ZnO arrester based FCL on circuit breaker. Strict mathematical formulas were presented, based on theoretical analysis and deduction, to properly describe the relationship between rate of rise of recovery voltage (RRRV) of circuit breakers and current limit factor, stray capacitance as well as short-line fault distance. According to these formulas, detailed computations were carried out to fully account for the concrete impacts on RRRV from every principal parameter, and were correlated with the conclusions drawn by simulations in previous publications available, which verified effectively of the proposed analyzing methodology. The research results present analytical basis and theoretical reference for the parameter optimization of ZnO arrester based FCL andreliable selection of the breaking characteristics of HV circuit breakers.This article also simulated the influence of ZnO arrester based FCL on power quality. Installed in the distribution network, FCL can not only limit fault current level, but also restrain voltage sags and hold back harmonics passing the circuit, thereby can clearly improve power quality.