Power Network Protection Using Wide-Area Measurements Considering Uncertainty in Data Availability

The wide-area measurement system (WAMS) is being incorporated in power systems for improved performance of monitoring, control, and protection schemes. During unavailability of synchrophasor data from critical buses, schemes utilizing the WAMS may become inactive or susceptible to malfunction. WAMS data may not be available due to failure of communication or measuring instruments. This paper proposes a WAMS-data-based method to identify transmission line faults for data unavailability from critical buses. For this purpose, three indices based on network power flow are proposed. The first index selects buses in the disturbance area in a network by observing the variation in current injections. A subsystem is formed thereafter using the selected buses. The second index calculates the input and output power difference for the subsystem to detect a fault in the network. Finally, a voltage-based index is used to identify the faulted line. The proposed method was tested for the New England 39 bus system with/using PSSE simulations and real-time simulations in OPAL-RT. Results show the ability of the algorithm to detect faulted line(s) in the network even with data loss from selected buses and simultaneous faults. The method is also capable of distinguishing faults from power swing and load encroachment conditions.