Robust State Estimation Method for Adaptive Load Frequency Control of Interconnected Power System in a Restructured Environment

Abstract

Handling varying uncertainties in renewable energy generation and load demands are major challenges to the restructured power system environment. This article proposes the design of a novel control methodology using a robust UIO for dynamic state estimation and an interval type-2 fuzzy logic controller for adaptive LFC of interconnected power systems with high penetration of renewable energy in a restructured power system environment. The capability of the proposed robust UIO to independently estimate the true state of the power system regardless of unknown inputs or disturbances that impact the frequency stability in real time is demonstrated by the asymptotic zero property of the state estimation error. This is supported by using an interval type-2 fuzzy logic controller in the LFC loop of each area of the interconnected system to efficiently damp frequency oscillations, thereby improving power system stability and resilience. The performance of the proposed methodology is evaluated using a modified two-area power system in the restructured environment. The results obtained from the stability and LFC analyses during severe operating conditions demonstrated the robustness of the proposed control framework to unknown inputs and unprecedented variations that can affect the frequency stability of the system.