Ancillary service quantitative evaluation for primary frequency regulation of pumped storage units considering refined hydraulic characteristics

Abstract

With the deepening of global energy transformation process, a higher proportion of variable renewable energy (VRE) is connected to power grid, and it is urgent to improve regulation capacity and operation efficiency of power grid. Pumped storage plants (PSPs) could provide important auxiliary services for power grids, and frequency regulation is a crucial function. Quantitative evaluation of primary frequency regulation (PFR) performance is a key issue for benefits of auxiliary services of PSPs and operation and management of power grid. In this paper, a quantitative evaluation method for PFR performance of pumped storage units (PSUs) is constructed based on fuzzy analytic hierarchy process (FAHP). Five important evaluation indexes are selected based on the auxiliary service compensation in electricity markets in China and the USA. The PFR performance score is calculated through this evaluation method. A refined numerical model of PSUs is established taking a PSP in China as an example. Different operation schemes are set up by inputting different frequency disturbance signals, changing control system characteristics (governor parameters Kp, Ki, bp, and frequency dead zone) and hydraulic characteristics (time constants Tw, Ts, Ty), and the evaluation method is used to quantify PFR performance of PSUs under each scheme. This study reveals the influence mechanism of governor parameters, matching rules among time constants, and frequency dead zone on dynamic response of PFR and auxiliary service performance. The results show that the method provides analytical means and intuitive reference for comprehensive quantitative evaluation for PFR performance of PSUs, and contributes to the guidance of multi-parameter matching and promotion of the coordination between power plants and power grids.