An improved voltage phasor estimation technique to minimize the impact of CCVT transients in distance protection

This paper describes the impact of the transient response of coupling capacitor voltage transformers (CCVTs) on the performance of distance relays. Several factors that affect the frequency and time responses of CCVTs are considered. The effect of the transient response on phasor estimation is illustrated. A new least squares phasor estimation technique, which uses the knowledge of the frequency of the CCVT transients, is presented. A sample case, taken from a set of studies, is included to demonstrate the performance of the proposed approach