An improved fault detection and phase identification for collector system of DFIG-wind farms using least square transient detector coefficient

Electricity generated from the present-day large-capacity wind turbine generators (WTGs), i.e. doubly-fed induction generators (DFIGs), is commonly accumulated at the collector station by intricate collector lines (CLs) and then evacuated through the transmission line (TL) to the utility grid. The traditional over-current protection of such CLs may face difficulty due to variable control action of the WTG and power electronic-based voltage support devices (e.g. STATCOM) at collector substation bus (CSB). In this paper, a superimposed least-square approach based transient detector phase coefficient of modal current for detecting faulty CLs/TL and magnitude coefficients of phase currents for identifying the accurate faulty phase of the CLs for two standard multi-segment test systems. The algorithm is also validated through the modified IEEE 9-bus system. The detection and phase identification times of faults are found less than 8 ms and 15 ms, respectively from 3600 fault cases. These test systems are modeled in RSCAD software and validated through RTDS hardware simulator. Further, the traditional over-current scheme is verified using SEL-451 PMU and SEL-3573 PDC data. Finally, the proposed algorithm is performed in MATLAB and validated through OPAL-RT (OP5600) using the generated data from RTDS. The use of single-end data at a lower sampling rate (1 kHz), obtained results and real-time validation justify the efficacy of the proposed method.