Abstract—Most of the load-frequency control problems in the literature have been treated as single-objective optimization problems till date. This paper suggests a new design of Multi-Objective Evolutionary Algorithm (MOEA) based decentralized load-frequency controllers for interconnected power systems with Governor Dead Band and Generation Rate Constraint nonlinearities and Superconducting Magnetic Energy Storage (SMES) units. Addition of a superconducting magnetic energy storage unit significantly improves the transients of frequency and tie-line power deviations against small load disturbances, by exhibiting favorable damping effects. The proposed controller fulfils two main objectives, namely, minimum Integral Squared Error of the system output and maximum closed-loop stability of the system. The design is implemented on an interconnected two-area thermal power system. Simulation results show that the proposed controller provides better dynamic responses with minimal frequency and tie-line power deviations, quick settling time and guarantees closed-loop stability margin even in the presence of system nonlinearities.

Index Terms—Governor dead band, Generation rate constraint, Load-Frequency Control, Multi-Objective Evolutionary Algorithm, Superconducting Magnetic Energy Storage.

S. Ganapathy is with the Department of Electrical Engineering, Annamalai University, Annamalainagar, Tamilnadu-608002, India. (corresponding author. phone: +91-4144-228535; fax: +91-4144-238275; e-mail: ganapathy1967@gmail.com).
S. Velusami is with the Department of Electrical Engineering, Annamalai University, Annamalainagar, Tamilnadu-608002, India. (e-mail: profvels@ yahoo.co.in).

Cite: S. Ganapathy and S. Velusami, "Design of MOEA based Decentralized Load-Frequency Controllers for Interconnected Power Systems with Nonlinearities  and  SMES  Units,"  International  Journal  of  Computer  and
Electrical Engineering vol. 2, no. 1, pp. 45-53, 2010.