Optimization Strategy for Joint Day Dispatch of Pumped Storage Thermal Power Plants Based on Dynamic Frequency Constraints

With the increase of the proportion of new energy connected to the grid and replacing some synchronous units, the virtual inertia of new energy has not been widely used, which leads to the problems of the decline of the system inertia level and the decline of frequency stability. Due to its natural advantages, pumped storage units can provide inertia support like traditional synchronous units when they are in the state of power generation, and enhance the frequency stability of power grid; When the pump is in the pumping state, it can also cut off the pump quickly to offset the unbalanced power caused by the disturbance. Therefore, this paper takes pumped storage as the starting point, discusses the frequency modulation strategy, and establishes the frequency constraint to ensure the frequency stability based on the inertia index. The effectiveness of the frequency modulation strategy and model proposed in this paper is proved by a numerical example. The addition of pumped storage can greatly improve the anti disturbance ability of the system and enhance the frequency stability of the system.