Emergency fault affected wide-area automatic generation control via large-scale deep reinforcement learning

Abstract

When a complex large power system is in an emergency, the conventional discrete emergency control strategy implemented will cause excess load or derivative accidents like line power overload, thereby raising the operation risk. To overcome the problems of excessive/insufficient regulation and subsequent accidents in the above context, this paper proposes a wide area automatic generation control (WA-AGC) framework, which integrates the emergency control strategy and a performance-based frequency regulation market mechanism. According to the frequency status of the power system, WA-AGC divides the AGC into four intervals, emergency AGC (EAGC), conventional AGC (CAGC), AGC transition and optimal power flow (OPF). These four together realize a comprehensive optimization of frequency and system stability as well as economy Based on the above framework, a swarm agent exploration distributed multiple delayed deep policy gradient algorithm (SAE-MD3) is developed, which uses multiple explorers with different exploration strategies for distributed optimization. In addition, several technologies are introduced to prevent Q value overestimation and generate a more robust optimal AGC strategy. Afterward, the effectiveness and feasibility of WA-AGC are verified through the simulations of an IEEE-9 two-area system and an IEEE-118 two-area system. Compared to conventional AGC strategies, the WA-AGC algorithm reduces the constraint violation time of the power line by 92.06% and the power generation cost by 0.27% as well as improves the CPS1 index by 0.04%.