Decentralized Robust Controller Design for Strongly Interconnected Generators

Abstract

Stability of multiple interconnected generation systems are prone to the inter-area power oscillations among them. This issue becomes more significant when the interconnection strength among the generation systems is stronger. In previous control strategies, the coupling effects have been considered as undesired disturbances that leads to failure in tackling this issue when the generation systems become strongly coupled. Thus, in this paper a new control scheme is presented to address this strong coupling effect by designing robust decentralized controllers in a sequential way to tackle the load frequency control problem in a three-area generation system connected through tie-lines. Three robust decentralized controllers are designed for the three areas by using the $\mu $ -synthesis technique. The model of tie-line coupling among the generation areas is taken into account in the design of sequential controllers. Moreover, the decentralized controllers are designed in such a way that the entire control system is robust against all the parameter variations and uncertainties. Based on the simulation results, the proposed decentralized controllers outperform the conventional independently designed controllers in terms of variations in the coupling strength in the tie-line.

Keywords

• Interconnected systems
• μ-synthesis
• robust controller
• sequential design
• synchronous generator
• tie-line