Development of new concept optical zero-sequence current/voltage transducers for distribution network

Optical zero-sequence current-voltage transducers for detecting faults in nongrounded distribution networks were developed. The detection part can be electrically isolated from the ground by use of the divide method, in which there is a stray capacitance between line and ground. Zero-sequence current and voltage produced by the imbalance of error tolerance among the three-phase sensors were reduced by residual signal reducer processing. By artificial ground default testing and aging testing, it was confirmed that the transducers performed sufficiently for application to distribution networks