Small-Signal Stability Improvement of Grid Integrated DFIG and SOFC System with SSSC-POD Using Coordinated Optimization Approach

Abstract

Background: Focusing on the stability problems brought by integrated wind power and fuel cell, the objective of this paper is to analyze small-signal stability and improvement of a hybrid renewable energy system connected with doubly-fed induction generators (DFIGs) and solid oxide fuel cells (SOFCs) energy with the static series synchronous compensator (SSSC) and power-oscillation damper (POD). Methods: For this purpose, a SSSC-POD controller is designed and the state-space representation of such a hybrid power system for modal analysis is developed. Then an approach of coordination and optimization of SSSC-POD parameters based on genetic algorithm (GA) and modal analysis is proposed to further improve the power system small-signal stability. Results: Several designed scenarios, including changing the tie-line power, POD input signal and SOFC power output, are considered in IEEE two-area system to test the proposed method through small-disturbance eigenvalue analysis and time-domain simulations. Conclusion: Simulation results demonstrate that the proposed approach can effectively suppress the local and inter-area oscillations and improve power system stability.