Real Time Simulation for Testing a Variable Speed Pumped Hydro Energy Storage Plant Connected to an EHV Transmission Network using RTDS

India’s commitment to the United Nations Framework Convention on Climate Change, is to reduce the carbon footprint by 45% and energy requirement from non-fossil fuel sources by 50% by 2030. This energy transition incorporates intermittent sources like solar and wind having low inertia and fast control characteristic of the converters. This poses grid stability issues caused by rapid frequency collapse during faults and islanding. Energy storage systems enable the reliable operation and integration of renewable energy sources in power grid by providing frequency control and load leveling services to power grids with high penetration of renewables. Pumped hydro storage can balance short-term intermittent generation by providing fast power ramps, as well as provide long-term load-leveling during seasonal weather patterns. In this study, a variable-speed pumped storage machine is taken as the test case. Large head variation makes these projects even more challenging, and hence, the effect of grid conditions on the machines were thoroughly studied for the reliable and efficient operation of the pumped storage plant. Conventional modeling of the hydro turbines is followed for the turbine mode of application, and for the pumping mode simulation, the system implemented the pump head-flow curve with gating effects that provides additional friction to the system. Furthermore, the modeling is carried out using the Real Time Digital Power System Simulator to realize the real-time response of the machine towards the transients occurring in the system.