Sizing of energy storage system for grid-connected inverters to enhance system stability

• Main Author: Chua, Shawn Zheng
• Other Authors: Gooi Hoay Beng
• Format: Final Year Project
• Language: English
• Published: 2019
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Electric power::Production, transmission and distribution
• Online Access: http://hdl.handle.net/10356/77885
• Institution: Nanyang Technological University

The increase in solar, wind and other renewable energy usage within the power grid has led to an overall decrease in generators installed in conventional power plants. This has inevitably led to the grid being more vulnerable to frequency changes as generators act as a source of inertia whenever a contingency scenario occurs. Energy storage systems (ESSs) can therefore be used to emulate the inertia that generators provide. ESS specifically activates during the inertial response (IR) and primary frequency response (PFR) during the occurrence of a fault. However, the optimal size and mix of ESS to be used to support the grid still requires much research and this is important as grids need to remain stable as loads may be shed or damaged if certain frequency boundaries are crossed. This study covers multiple topics within power systems ie. power system stability, synchronous generators, solar photovoltaics, wind turbines, energy storage systems and their control theories, the methodology of sizing an ESS, offline/real-time testing and finally control hardware-in-the-loop. A general methodology for the sizing of ESS for both the 12-bus transmission and 33-bus distribution systems were explored, whereby certain contingency scenarios were simulated and the frequency waveforms recorded to demonstrate the role of the ESS in providing IR and PFR. The simulations were conducted in both Simulink and real time (OPAL-RT), after which the experiment was taken a step further by implementing the control of the ESS in a hardware-in-the-loop setup (dSpace).