A UPFC‐based robust damping controller for optimal use of renewable energy sources in modern renewable integrated power systems

Abstract

This paper proposes coordinated design of wide-area damping controller (WADC) in the presence of renewable energy resources in a large-scale power system. To tackle with constant and time-varying delays in wide-area system, a robust criterion based on H∞ has been used for the coordinated WADC design. By using an auxiliary function in Lyapunov function, conservatism of linear inequality matrix (LMI) is reduced, such that larger delay margin and larger feasibility region is obtained in the presence of delays. The wind farms here are composed of doubly-fed induction generator (DFIG) and squirrel-cage induction generator (SCIG), which are connected to common bus of photovoltaic (PV) system by using unified power flow controller (UPFC). Then, the renewable energy units are integrated with 10 and 16-machine power systems. Afterwards, by identifying oscillating modes, the coordinated design of WADC is carried out for rotor-side-converter (RSC) in DFIG, DC/AC converter in the PV units, shunt converter (SHC) in UPFC, and power system stabilizer (PSS). Different scenarios of power system operating conditions are considered to evaluate performance of the proposed approach. The simulations in power system analysis toolbox (PSAT) and programming in MATLAB demonstrate effectiveness of the conducted method.