Fault analysis method of integrated high voltage direct current transmission lines for onshore wind farm

Voltage source converter (VSC) based high voltage direct current (HVDC) transmission is most suited for the wind farm as it allows flexibility for reactive power control in multi-terminal transmission lines and transmits low power over smaller distance. In this work, a novel method has been proposed to detect the fault, identify the section of faults and classify the pole of the fault in DC transmission lines fed from onshore wind farm. In the proposed scheme, voltage signal from rectifier end terminal is extracted with sampling frequency of 1 kHz given as input to the detection, classification and section discrimination module. In this work, severe AC faults are also considered for section discrimination. Proposed method uses fuzzy inference system (FIS) to carry out all relaying task. The reach setting of the relay is 99.9% of the transmission line. Besides, the protection covers and discriminates the grounding fault with fault resistance up to 300 Ω. Considering the results of the proposed method it can be used effectively in real power network.