A New Adaptive Impedance-Based LOE Protection of Synchronous Generator in the Presence of STATCOM

This paper presents a new adaptive distance function for loss of excitation (LOE) protection of synchronous generator in the presence of STATCOM. Nowadays, the Berdy distance function is most widely utilized as the main protection for LOE fault. However, the presence of FACTS devices has adverse impacts on the operation of this function. FACTS devices cause LOE protection function to underreach. Also, these devices cause a substantial delay on the performance of the distance LOE function. Consequently, due to the operational characteristic of the LOE distance protection function, a new adaptive method is proposed to remove STATCOM effects. The proposed scheme compensates theses undesirable effects on calculated apparent impedance by unsynchronized measurements at STATCOM terminals. In this method only, the Thevenin model parameters at STATCOM terminals are required to send the relay location via communication channel. The simulation results demonstrate that the proposed modified method enhances speed, security, and sensitivity of the LOE distance function when STATCOM is in service.