A novel parameter identification-based distance protection algorithm for transmission line connecting to wind power plant

In resent, large-scale wind power plant (WPP) integrating into transmission level and the transforming of over-head line (OHL) into underground cable (UC) bring significant challenges for existing relay protection in Denmark. This paper focuses on the phase-ground fault of an UC-based transmission system connecting to WPP. A novel parameter identification-based single-ended fault location method in time domain is proposed using the equivalent π model of transmission line. Due to the comprehensively considering of cable impedance, cable capacitance and transition resistance, the algorithm has high adaptability and the ability to endure the fault transition resistance in theory. Besides, the fault data before fault steady state including attenuation components are sampled to solve the differential equation for this time domain distance protection algorithm, namely, it can trip the breaker fast during the fault transient period. Finally, DIgSILENT simulation results verify the validity of the proposed protection method on UC-based transmission line with WPP integration.