Inverter Angle Minimization Based Control Approach for Dispatch of Distributed Energy Resources With Hybrid Energy Storage System

Abstract

This paper presents a novel voltage angle minimization based approach for grid inertia improvement using a Photo-Voltaic (PV) Distributed Energy Resource (DER) in conjunction with a fully active Hybrid Energy Storage System (HESS) comprising of battery and ultra-capacitor. PV and HESS are integrated at a common DC link that feeds a three-phase voltage source inverter (VSI) and a modified IEEE 123 bus power distribution system model is used for system validation. The proposed method successfully quantifies and differentiates grid dynamics from steady-state conditions by measuring the deviation of voltage angles between the generator and DER interconnection bus (Δδ). A Linear Quadratic Regulator (LQR) controller with a quality function is formulated to minimize (Δδ) during the event of grid dynamics for frequency regulation of the distribution system by optimal dispatch of HESS. The proposed approach controls the Rate of Change of Frequency (RoCoF) and primary frequency and secondary frequency response without the need for frequency-droop information while ensuring grid stability through locally controlled PV DER.