Analysis of Load Frequency Control Problem for Interconnected Power System Using PID Controller

This paper present the analysis of load frequency control problem for interconnected power system using the PID controller. Any small sudden load change in any of the areas causes the fluctuation of the frequencies of each and every area and also there is fluctuation of power in tie line of interconnected power system. Frequency should remain nearly constant for satisfactory operation of a power system because frequency deviations can directly impact on a power system operation, system stability, reliability and efficiency. Large frequency deviations can damage equipments, degrade load performance, overload transmission lines and affect the performance of system protection schemes. A Load Frequency Control (LFC) scheme basically incorporates an appropriate control system for an interconnected power system, which is heaving the capability to bring the frequencies of each area and the tie line powers back to original set point values or very nearer to set point values effectively after the sudden load change. This can be achieved by the use of conventional and modern controllers. In this proposed research work PID controller has been applied for LFC of two area power systems. The parameters of the PID controller are tuned by three different methods names as Ziegler-Nichols (Z-N) Method, Simplex Search Method and IMC method for better results. It is seen that the results obtained are far better than the conventional controller. Keywords— IMC, LFC, PID, set point, Tie line.