ON ROBUST-CONTROL ANALYSIS AND DESIGN FOR LOAD FREQUENCY REGULATION

This paper addresses analysis and design issues in Load Frequency Cont rol (LFC) for a power system entity that participates in an interconne ction. The basic, physical control mechanisms are the same whether the entity is a vertically integrated utility, an independent system oper ator, or a virtual control area in a fully de-regulated market. Goals of this paper are twofold: to examine a rationale for known heuristic design guidelines, and to suggest an orderly methodology for control s ynthesis. Motivated by the large uncertainty in dynamic models of powe r system components and their interconnections, this paper proposes a physically motivated passivity objective as a means to achieve effecti ve closed-loop control. Quantitative feedback theory provides convenie nt graphical tools for suggested design and analysis methods. A simula tion model of a two system interconnection is used as an illustration.