THE PHASOR COMBINATION DIFFERENTIAL PROTECTION FOR LE-BLANC TRANSFORMERS

The main electrical protection of Le-Blanc connection transformers tha t supply the single-phase power to electric railway in Taiwan is the o vercurrent protection. This paper presents a mon complete protective s cheme, the differential protection, for Le-Blanc by phasor combination method. The calculation procedure and the good mismatch results of a practical design example using the parameters of a Le-Blanc transforme r of Taiwan Railway Bureau(Tairail) are described in this paper. In ad dition, using the normal current transformers and electromagnetic type transformer differential relays to completely construct the protectiv e scheme is another merit of this algorithm.