One-terminal fault location for VSC-HVDC transmission lines based on principles of parameter identification

To ensure reliable operation of voltage source converter HVDC (VSC-HVDC) transmission system, a one-terminal fault location method for VSC-HVDC transmission line is proposed. Because high-capacity capacitors are connected to both ends of VSC-HVDC transmission line, so during the fault location the converter station systems at both ends of VSC-HVDC transmission line can be equivalent to capacitors in the network of zero-mode component, and by means of the principle of parameter identification the differential equations in time-domain, which contains two unknown parameters of fault distance and transition resistance, can be listed, and solving this equation by least square optimization both fault distance and transition resistance can be attained, thus the fault location is implemented. The proposed method only needs single end electric quantities and is undemanding to sampling frequency, besides, theoretically this method is not affected by transition resistance, so it can meet the demand on fault location for VSC-HVDC transmission lines. Results of PSCAD simulation show that the proposed method can implement accurate fault location for VSC-HVDC transmission line while the maximum location error is not more than 1%.