A Root-Cause-Analysis Based Method for Fault Diagnosis of Power System Digital Substations

Fault Diagnosis of power systems has attracted great attention in recent years. In the paper, the authors present a Cause-Effect fault diagnosis model, which takes into account the structure and technical features of a digital substation and performs root-cause-analysis so as to identify the exact reason of a power system fault occurred in the monitored district. The Dempster/Shafer evidence theory has been employed to integrate different types of fault information in the diagnosis model aiming at a hierarchical, systematic and comprehensive diagnosis based on the logic relationship between the parent fault node and the child nodes like transformers, circuit-breakers, and transmission lines, and between the root and child causes. An actual fault scenario is investigated in the case study to demonstrate the capability of the developed model in diagnosing malfunctions of protective relays and/or circuit breakers, miss or false alarms, and other faults often encountered at modern digital substations of a power system.