The Influences of UPFC on the Performance of LOE Protection of Synchronous Generator

Abstract

The primary protection of the power system is a synchronous generator loss of excitation (LOE) protection which is used to measure impedance. The impedance is calculated at the generator terminal by measurement of current (I) and voltage (V). The relay performance is conducted using the impedance trajectory nature. The R-X impedance measurement technique is used for assessing a synchronous generator's LOE performance. Different Flexible AC Transmission Systems (FACTS) devices have been used to improve the power system performance, although the main disadvantage of this FACTS controller is that it malfunctions the LOE relay by changing the impedance. The existence of a UPFC causes a delay in the operation of the LOE relay and causes conditions such as overreach and under-reach. This article examines UPFC's influence on the LOE relay. The mitigation technique is also implemented using Simulink/MATLAB.