基于自振回路的柔性直流线路故障测距方法OA

Flexible DC transmission lines are subject to a range of faults,including ground faults,from time to time.To ensure the reliable operation of the voltage source converter HVDC(VSC-HVDC)sys-tem,it is necessary to study its fault ranging technology.A new method of fault ranging for flexible DC transmission lines with additional self-oscillation loops is proposed.The scheme starts from the fact that reactive power is related to line inductance-capacitance,and a self-oscillating loop is attached to the large DC capacitor that can be re-integrated into the system after a trip,and use the reactive power and current provided by the circuit and the self-oscillation frequency as a criterion.The inductance wave-form is obtained by measuring the resulting line reactive power and current,and the inductance value is obtained by averaging to perform fault ranging.Finally,a simulation model is built using PSCAD/EMT-DC software,which verifies that the proposed scheme is not affected by the transition resistance and is ef-fective for fault location.The proposed scheme can meet the fault ranging requirements of flexible DC transmission lines by using only single-ended quantities for ranging.