Load Frequency Control through DFIM-based Pumped Storage Hydro

Abstract

Pumped storage hydro (PSH) with doubly-fed induction machines (DFIMs) is a viable alternative to the conventional PSH with synchronous machine. This paper investigates the ability of the DFIM-based PSH to provide the required support to frequency disturbances due to large output variation of high voltage (HV) grid connected solar farms. This paper is concerned with frequency support while the DFIM is operating as a pump. It is found that the nonlinearities of a centrifugal load connected to the grid can be accommodated by the use of model reference adaptive control (MRAC) system. Using MRAC, speed reference tracking can be improved significantly. Also, an algorithm has been investigated to supervise the droop constant of the DFIM so as to enhance the rate of change of frequency (ROCOF), which when used simultaneously with the MRAC based speed control, results in a better frequency profile.