Quasi oppositional harmony search algorithm based controller tuning for load frequency control of multi-source multi-area power system

• LFC study of single-area and two-area interconnected power system is carried out.
• LFC study of the studied models is carried out following step load perturbation.
• Comparative performance analysis among I, PI and PID controller is made.
• The gain(s) of the controllers are tuned using a novel QOHSA.
• Presence of DC link in parallel to AC links improves overall dynamic performance.

This paper deals with the load frequency control (LFC) study of single-area and interconnected two-area power system having diversified power sources. The two areas considered in the present study are identical. Each area is having thermal, hydro and gas based power plants. Split-shaft model of gas turbine is used in the present work as one of the diversified generating unit for the purpose of LFC study. Optimal gains of the classical controllers (like integral controller, proportional–integral controller and proportional–integral–derivative (PID) controller, one installed at a time in the studied models) are obtained by using a novel music-inspired metaheuristic harmony search algorithm (HSA) which incorporates quasi opposition based learning technique for memory initialization and also for generation jumping. Single-area power system with diverse power sources is considered and its optimal transient performances are obtained and compared for step load perturbation. The same approach is further extended to two-area interconnected power system consisting of diverse power sources with nominal values of area input parameters. The performance of PID controller is found to be the best one for the studied power system models. It is also revealed that the performance of the interconnected two-area power system with AC–DC tie line is better in comparison to AC tie line.