Power System Optimal Dispatch Integrating the Responsive High-Speed Train Fleet

High-speed trains (HSTs) are electrically powered and have a bi-directional interaction with power grids. Specifically, they consume a large amount of power in the traction state, usually reaching tens of megawatts, and return power to the grid in the braking state. As long as the departure and arrival timetables are satisfied, their motion states have considerable flexibility, which means their real-time power consumption can be regulated. Considering the urgent demand for regulating resources in modern power systems with a high proportion of intermittent renewable energy, the untapped power reserves of HSTs are of great significance. To exploit the flexible response capability (RC) of the HST fleet (HSTF), this paper investigates a real-time dispatch optimization method for power systems integrating the responsive HSTF. First, the power response mechanism of the HSTF is elaborated in terms of train operating characteristics. An interaction framework is constructed to coordinate optimal operation between the power system and the railway system, enabling cooperative dispatch despite privacy and information barriers. Then, a spatiotemporal RC assessment and aggregation method for the HSTF towards power system real-time dispatch is proposed, which can assess the RC of both independent as well as group of HSTs coupled together by safety spacing constraints. On this basis, a bi-level real-time optimal dispatch model for power systems integrating the responsive HSTF is proposed. In the upper level, the power system is optimized based on OPF technique. In the lower level, the HST operation is optimized to minimize the cost of electricity procurement. Finally, numerical results on an IEEE test system coupled with a railway system demonstrate that the proposed method improves the economy and reliability of power system operation.