A method of single and both fault locating and evaluating through or substitution on tree type power network

The problem of fault diagnosis of a tree type power network with single or both short-circuit or open-circuit and a contact resistance of arbitrary value between lines is studied. Based on or substitution, the method presented here is suitable for fault locating and contact resistance evaluating. Principles of diagnosis are discussed, diagnosis equations are established, and diagnosis algorithms are presented. Finally, examples for diagnosis a five-branches tree-type power network with short-circuit and open-circuit are given.