A Statistical Decision Theoretic Approach to Digital Relaying

Digital relaying is logically decomposed into three successive processes-sensing, evaluating, and discriminating ones. The first process transforms the system voltage and current into digital forms. The middle process produces the criterion value through a specific measuring algorithm. Finally, the last process discriminates a faulted condition based on the criterion value. One of the important strengths of the digital systems over the analog ones is the ability of making decisions in the final process, which so far has been neglected in the relaying field. With the probabilistic natures in the fault condition in mind, this paper presents one of the approaches toward this direction through the statistical decision theory, and also presents a determination method of the sampling rates for the digital relays.