Wide-Area Measurement-Based Backup Protection for Power Network With Series Compensation

This paper presents a synchronized phasor measurement-based wide-area backup protection scheme which compares the magnitude of sequence voltages of buses at a system protection center to identify the bus closest to the fault. Then, the sign of cosine of the angle between voltage and current at both ends of all lines connected to this bus are compared to identify the faulted branch. The technique is tested for various faults resulting in voltage/current inversion in a series-compensated line and during load encroachment and power swing conditions using data simulated through EMTDC/PSCAD for a nine-bus, three-machine power system. The scheme is found to be accurate and fast. With today´s synchronized phasor measurement technology and communication system, the proposed scheme can overcome the limitations of the conventional backup protection scheme.