A Novel Fault-Location Algorithm for Long Transmission Lines Compensated by Series FACTS Devices

This paper introduces a new noniterative fault-location algorithm for long transmission lines compensated by a series flexible ac transmission systems (FACTS) device. In the proposed algorithm, synchronous voltage and current samples from both ends of the transmission line are used and the distributed parameter line model in the time domain is applied. Due to the difficulties in the modeling of the series FACTS devices during a fault, the presented method does not use the model of the series devices. In this paper, the fault-location problem is converted to an optimization one in which the location and resistance of the fault are the decision variables. The proposed method includes three stages. Two fault locations are obtained, corresponding to the first two stages. In stage three, the obtained results from stages 1 and 2 are compared, and the correct fault location is selected. The proposed algorithm is a noniterative one and it is suitable for transmission lines compensated by any series FACTS device which could have the overvoltage protection and can be in any operating mode. The performance of the proposed algorithm is evaluated under different structural and fault conditions. The simulation results confirm the accuracy of the proposed algorithm.