Performance Analysis of Price Based AGC for Indian Power System under ABT Mechanism

Availability Based Tariff (ABT) mechanism was instituted in Indian power system with an aim to maintain grid discipline and bring about more accountability and responsibility among the participants in the system. Significant improvement in frequency profile is observed within few years of its implementation. But still some more efforts are required from the generator's side to achieve improved frequency stability and to economize overall system operation. In this paper, a control scheme for Automatic Generation Control (AGC) is presented using price signals to minimize the Unscheduled Interchange (UI) charge through mitigating the frequency deviation and to adjust the generation economically or as directed by the system operator at various units in the event of disturbance. In order to improve the dynamic performance, fuzzy PID controller with two inputs and single output is used in this scheme. Performance analysis is carried out to check the robustness of the proposed scheme by subjecting it to different parametric variations and nonlinearities. The scheme is implemented in a single area system with four thermal generating units. It is clear from the results that the control scheme is robust, minimizing UI charges by maintaining rated frequency and the perturbations in load can be adjusted economically or as desired among the generators.