Complex Frequency-Domain Oscillation Analysis of the Pumped-Storage Systems

Abstract

Hydraulic impedance, as an efficient frequency-domain analysis alternative, has been widely utilized in hydraulic transient analysis for decades. Since the mathematical expressions of hydraulic systems with complicated pipe networks are usually rather complex, it is difficult for the traditional continuous impedance method to obtain the analytical solutions to the system’s frequency responses directly. Therefore, an equivalent circuit modeling-based discrete impedance method is proposed to mathematically express the hydraulic systems of a pumped storage plant system with complicated pipe networks. Through drawing an analogy between various hydraulic facilities and different types of electrical circuits, the equivalent circuit topology of any hydraulic system can be obtained according to the circuit theory in electrical engineering. The oscillation analysis of the pumped-storage power plant is conducted, and influences of the pump-turbine impedance on the system’s oscillation characteristics have been discussed.