Dynamic response and governor tuning of a long penstock pumped-storage hydropower plant equipped with a pump-turbine and a doubly fed induction generator

Abstract

In this paper, the dynamic response of a long penstock pumped-storage hydropower plant which is equipped with a single pump-turbine and a doubly-fed induction machine, is analyzed in detail in generating mode. The pumped-storage hydropower plant is connected to a small island power system with thermal generation, and provides load–frequency control under the orders of an automatic generation control system. The output power of the pumped-storage hydropower plant is assumed to be controlled by the rotor-side frequency converter. The unit running speed is controlled by an isochronous PI governor. The dynamic response of the pumped-storage hydropower plant is analyzed by using a linearized reduced order dynamic model, which considers the elastic water column effects in the penstock. Two governor tuning criteria are proposed in the paper: one is devised from the root locus analysis of the plant dynamic model, and the other one is based on a Pareto approach. The proposed tuning criteria are compared with each other and with a recently published tuning criterion through a set of commonly used performance indexes and by means of simulations with a nonlinear dynamic model.