Characteristic Analysis and Optimal Regulation of Primary Frequency Regulation Condition in Low Water Head Area Based on Hydraulic-Mechanical-Electrical Coupling Model of Pumped Storage Unit

Abstract

Pumped storage power station is an important regulating tool for peak load regulation and frequency regulation of the power grid, especially its primary frequency regulation function, which is of profound significance for the safety and stability of the power grid. As the core equipment of the pumped storage power station, the reversible design of the pump turbine makes it easy to have hydraulic fluctuation and mechanical instability when the unit runs to the “S” characteristic area, which will cause the frequency oscillation of the generator under the condition of primary frequency regulation. Therefore, some innovative work is studied in this paper: (1) an accurate hydraulic-mechanical-electrical coupling system mathematical model of pumped storage unit regulation system (PSURS) is established based on full characteristic curve of the pump turbine and seventh-order synchronous generator and excitation system; (2) the dynamic response characteristics of primary frequency regulation of pumped storage unit (PSU) under different water heads and different frequency disturbances are analyzed by numerical simulation; (3) in view of the unstable condition of the unit under the large frequency disturbance when it operates in the low head and small load area, the objective optimization function considering the ITAE index of hydraulic, mechanical, and electrical factors is proposed; and (4) fractional-order PID controller and the bacterial-foraging chemotaxis gravitational search algorithm (BCGSA) combined optimization strategy is used for PSURS optimization regulation and parameter optimization. The results show that the joint optimization strategy proposed in this paper has smaller objective function value, and makes the PSURS pass through the unbalanced area quickly, with better primary frequency regulation speed and smaller regulation depth.

Nonlinear Modeling of Dynamic Characteristics of Pump-Turbine

“…A pump-turbine is the core component of a pumped storage unit [1], and its dynamic characteristics play a decisive role in the stability of a hydropower station [2][3][4][5][6]. Therefore, accurate modeling of the pump-turbine is particularly important for the stability of the hydropower station's governing system.…”

Research on control strategy of f ull‐ s ize converter‐based variable speed pumped storage unit in power generation condition

“…Pumped‐storage power plants are large in scale, fast in working conditions, have functions such as peak shaving and valley filling, frequency modulation, and phase modulation, 1 and can be used to smooth the output power of renewable energy 2‐4 . It is of great significance to solve the problem of the safe and stable operation of the power grid caused by the large‐scale development of new energy such as wind power, and to reduce the operating cost of the power system 5 …”

Multi-scale Oscillation Characteristics and Stability Analysis of Pumped-Storage Unit Under Primary Frequency Governing Condition with Low Water Head Grid-Connected

“…Qiu et al [27] studied how pumped storage power stations can help improve the elasticity of power systems by performing PFGC in pumping and power generation modes (3) For optimal control, Wu et al [28] designed a fuzzy Fractional Order PID controller to improve the stability of the system. LV et al [29] used the optimization strategy of the combination of Fractional Order PID controller and bacterial foraging chemotaxis gravity search algorithm to optimize the regulation and parameters of the hydraulic turbine regulation system. Morel et al [30] proposed a robust control method to enhance the participation of variable-speed turbines in primary frequency modulation during network interference, so as to improve the closed-loop performance.…”