Transmission Line Back-up Protection with Unreliable PMU Data

Phasor Measurement Units have been widely used for transmission line back-up protection due to its speed and accuracy. Most of the methods completely rely on the accuracy of the PMU measurements for faulted line identification. However, PMU data may consist of measurement noise and missing data at some instants which may eventually lead to relay maloperation for many algorithms. The proposed scheme deals with the identification of faulted line using difference in estimated voltage phasor at a bus connected to a faulted line, which is derived from cubature kalman filtering (CKF) based dynamic state estimation. The scheme is tested on a New-England 39-bus system for several faulted conditions with the effect of missing data and measurement noise on the proposed scheme with measurement data from fewer PMUs.