PHASOR MEASUREMENT UNIT BASED WIDE AREA BACKUP PROTECTION SCHEME FOR POWER TRANSMISSION LINES

摘要

Protective relays, pivotal devices that can quickly identify and isolate fault area in power systems, is of great importance for ensuring power system security and reliability. This paper proposes a wide area backup protection scheme for identifying the faulted zone in power transmission lines. This scheme uses the data of wide area measurement systems (WAMS) with constrained number of phasor measurements which are synchronized by nature. First, the number of PMUs required for the scheme is optimized and then, the transmission network is divided into backup protection zones (BPZs) based on the PMU placement and network topology. Whenever the fault arises in a transmission network, the sum of zero and/or positive sequence currents entering the faulted BPZ highly increases, and hence, the faulted BPZ can be determined. This scheme determines the faulted zone quickly and precisely and thereby, reducing the effect of the various faults on the power grid. The proposed method is tested and simulated using a standard WSCC 9-bus system using MATLAB/Simulink.