RTDS Implementation and Stability Analysis of PSS4B Enabled Large Hydropower Plant Connected to a Series Compensated High Voltage Network

Power generation sources like hydropower plants are generally far away from the load centers and deliver power through a long transmission line. This situation may lead to the risk of low-frequency oscillations (LFO) which fall in the range of inter-area oscillations after any disturbance. Therefore, adequate measures need to be taken to mitigate these oscillations, which will otherwise cause widespread oscillations in the power system and as a consequence unit and plant shut down. It can be achieved by using an advanced power system stabilizer that dampens the system oscillation within an acceptable time frame for a large frequency range. This research considers a large hydropower complex of 1400 MW as the test system, which was modeled using an online simulator Real-Time Digital Power System Simulator Computer-Aided Design (RSCAD) and then using the high-performance RTDS processor, the actual response of the system was realized. The modeling of the system includes the generator, excitation system, power system stabilizer (PSS), and transmission line. A multiband power system stabilizer (PSS4B) was recommended in place of the existing power system stabilizer to improve the system's both steady state and transient response. The performance of the proposed controller was compared against the generic PSS and the existing PSS (PSS3B) of the test power plant. Furthermore, to check the controller's reliability, it was subjected to various abnormal conditions per the guidelines laid out by the Central Electricity Authority (CEA), India to simulate and evaluate the steady state and dynamic performance and confirm superior characteristics.