New Algorithm for Accurate Fault Location in Advanced Series Compensated Transmission Lines

In this paper a new accurate fault location algorithm in advanced series compensated transmission lines with TCSC (Thyristor Controlled Series Capacitor) is presented. In this algorithm time domain modeling of both transmission line and complete system of TCSC is considered. The algorithm includes two subroutines, one for faults in front of TCSC and another for faults in behind of it (TCSC). New parameter named (known as) FSI (Fault Section Indicator) is introduced and used for subroutines selection in the algorithm. In fact, FSI is virtual transient resistance of the TCSC element seen as a whole during the first cycle after fault inception. Voltages and currents samples at both ends of the transmission line are taken synchronously and used to calculate the fault location; however for computing FSI no synchronized data is needed. The algorithm accuracy is independent of fault resistance, fault inception angle and distance. Extent simulations carried out with ATP-EMTP software on a 400kV, 300km transmission system with TCSC installed in the middle of the line confirm capability and accuracy of the proposed algorithm.

Keywords:

Fault locator , Series compensated transmission line , Thyristor Controlled Series Capacitor (TCSC) , Digital relaying , Distributed line model