RESEARCH ON FAULT LOCATION BY RLC MODEL OF TRANSMISSION LINE

The Π equivalent circuits of transmission lines are commonly used in power system calculations. If this equivalent circuit is used in fault location of ordinary transmission line, the voltage and current at the terminal of the equivalent circuit is the very voltage and current at busbar and faulty position. If it is used in fault location of long distance high voltage transmission line, the algorithm is similar to the fault location for transmission line with distributed parameters. In this paper a fault location algorithm based on Π equivalent circuit is presented. In fact, the presented algorithm could be applied to different kinds of line models. When it is used for fault location of line with concentrated parameters, the formula estimating the faulty position is a forth order algebraic equation with real coefficients, the initial value for iteration should be selected appropriately to obtain proper solution. In the calculation example of this paper the fault simulation is performed by distributed parameter equation, the fault location is carried out by RLC line model. For 220kV transmission line the error of fault location results from this method is acceptable, but its algorithm is not so succinct as that based on the RL model. For 500kV long distance transmission line the fault location result is not so accurate as that based on the model with distributed parameters. Thus, this method could be only used in the fault location of 220kV transmission line and in the study on the comparison of fault location performances of different transmission line models.