Performance of Turbogenerator LOE Protection in FACTS Controllers Incorporated Transmission Networks

In this paper, extensive dynamic simulation studies are carried out to explore the performance of turbo generator loss of excitation (LOE) protection (Relay (40)) in FACTS Controller incorporated transmission networks. These studies have included the performance of LOE protection (Relay (40)) during two LOE modes, a complete LOE (due to field short circuit) and partial LOE (sudden drop of the excitation supply) during different generator loading conditions. The results of these investigations have shown that the presence of a FACTS Controller has a remarkable delay impact on the operation of the turbo generator LOE protection during LOE conditions. In addition, such a delay varies according to the generator loading and the LOE mode. Results have also shown that this delay is dramatically increased during partial LOE for all loading conditions. The dynamic simulations of a test benchmark have been conducted using the PSCAD/EMTDC software.