Accurate Overcurrent Relay Algorithm using Fundamental Component

This paper presents a new logic of operation for time overcurrent relays. With the application of the proposed technique, the sensitivity of time overcurrent relays is increased. In this paper, we have proposed a new relay algorithm using fundamental component where the trip time of relay is not set using only the initial current, rather it is updated using the current as the fault progresses. The functional structure is described and the logic of overcurrent relay is evaluated under a phase-ground fault condition. A significant decrement in the operating time is observed.