Power system stability enhancement in the presence of renewable energy resources

Abstract

In power systems, electrical networks constantly face unexpected events such as faults on lines or busses, sudden changes in load demand and loss of generation. When these events occur, the power grid can be plagued by uncontrollable loop currents, overloading equipment, and system instabilities, leading to cascade outages. In other words, all these events can cause the system to lose its stability. The concept of stability is essential in the power system, either with or without renewable energy. It is the system's ability to preserve its synchronism after disturbances have occurred. Maintaining synchronism is necessary in the power system due to the day-by-day expenditure of the system. This research focuses on enhancing the stability of a wind-integrated power system that is subjected to faults. The system stability is enhanced by using PSHP on a 100 MW wind power integrated network, the modified New England test system known as the 10-machines 39-bus system. Modern pumped storage hydropower plants (PSHP) based on doubly fed induction machines (DFIM), also known as variable speed PSHP, and conventional PSHP based on synchronous machines (SM), also known as fixed speed PSHP, both have distinct effects on the stability of a large-scale power system (FS). Comparing the effects of DFIM and SM-based PSHP in terms of the best stability improvement solution has shown that DFIM-PSHP presents better stability improvement results than SM-DFIM. Simulations were carried out using Digsilent Power Factory software, considering two study cases. The 1st study case is the stability improvement with a SM-based PSHP instead of a synchronous machine on Bus 10. The 2nd study is the stability improvement with a DFIM-based PSHP instead of SM-based PSHP. The two study cases were done under various scenarios, and it was shown that stability is best improved with the use of DFIM-based PSHP compared to SM-based PSHP.