DDL algorithm based short circuit current detection in DC circuit breaker

Drastically growing trend of DC power utilities is subsequently enhancing the need of better protection techniques which are hampered by less reliable fault detection methods. This paper presents a DDL based algorithm for short circuit current detection in a DC circuit breaker (DCCB). The algorithm is based on rise rate and increment parameters of the current. Viability of the algorithm is theoretically discussed for various abnormal conditions. Analysis of relationship between short circuit detection time and noise present in system current is preceded by exploration of experimental results of signal source based testing. In order to verify feasibility of the proposed method in real DC system, short circuit detection experiment has been performed on a medium voltage DCCB. Keeping in view the importance of quick detection of short circuit, time delays offered by various stages for the experimental setup are also analyzed in the paper. Thus, all the pertinent topics, ranging from verification methods to time delay analysis are incorporated in the paper and the achieved detection time is less than 300μs.