Bridge arm Fault Location Method for High Voltage Capacitor of DC Filter in HVDC Systems based on Current Characteristics

There are two kinds of methods to locate fault for high voltage capacitor of DC filter in HVDC systems, which include 1) directly observing the appearance state of capacitor, 2) manually measuring the value of capacitor unit. However, they fail to achieve satisfactory efficiency and pose a threat to operators' safety. Thus, this paper proposes a novel fault location method for high voltage capacitor of DC filter based on current characteristics of direction and amplitude. The direction change characteristics of unbalanced current and the amplitude relationships among the bridge arm branches of high voltage capacitor are analyzed. The degree of current amplitude change of bridge arm branch is defined to locate the position of faulty bridge arm. Performance of the proposed location method for high voltage capacitor of DC filter is evaluated based on time-domain simulation studies in the PSCAD/EMTDC software environment and experimental results are based on a real-time digital simulator.