Filtering effects of substation secondary circuits on power system traveling wave transients

The accuracy of traveling wave fault location systems are highly dependent on the frequency response of the substation coupling transducers. This paper presents an electrical equivalent model of a current transformer and the associated secondary cabling, where the electrical parameters have been measured from 330 kV devices or calculated from the geometry of the equipment. Frequency dependant models have been developed from this data using the alternative transients program to simulate the filtering effects of the secondary cabling impact on high frequency transient. The simulation results are then compared to signals observed by traveling wave recorders connected to the substation secondary cabling.