A Method for Controlled Fault Interruption Based on Predicted Current Behavior

A method for prediction of the behaviour of fault currents has been developed for the application of controlled fault interruption (CFI). A generic, asymmetrical fault current model is used for predicting viable interruption current zero times, to which the trip commands of a circuit breaker can be synchronized in order to interrupt with pre-selected (optimum) arcing times in each phase. Analysis-of-variance (ANOVA) testing of the model against sampled current values is used to regulate control of the algorithm. The algorithm has been tested in simulations with a wide range of fault current cases and found to predict target current zero times within plusmn0.5 ms, even in presence of large random signal distortion.