Enhancing Performance of Wide-Area Back-Up Protection Scheme Using PMU Assisted Dynamic State Estimator

Wide-area measurements consisting of phasor measurement information, are lately used for monitoring and protection purposes. However, due to certain constraints related to usage of phasor measurement units (PMU) at all the buses, optimal placement of PMUs are needed for wide area applications. Further, limitations of supervisory control and data acquisition measurements and erroneous PMU measurements due to noise and communication link failure at some instant leads to the requirement of dynamic state estimation (DSE) using PMU information. The proposed scheme deals with wide area back-up protection scheme utilizing cubature Kalman filtering-based DSE in conjunction with fewer PMU measurements for obtaining full observability. A voltage-based index is derived using the DSE information to identify the faulty line. The scheme is tested for several faulted as well as stressed conditions such as line outage, generator outage, load encroachment and voltage stressed conditions including measurement error and missing data at some of the PMU buses. Extensive test on New England 39-bus system indicate that the proposed wide-area back-up protection scheme can reliably take appropriate action for back-up zone.