Abstract:
The following work is to propose a new method of defining the area control error for implementing integral control AGC scheme for an interconnected power system. Conventionally, the area frequency deviations are biased with a parameter ‘Frequency Bias (B)’ and added to tie line power deviation to compose the area control errors. However, deciding a suitable value of ‘B’ has been a crucial and debatable issue over years. Many researchers have proposed different ways of deciding ‘most appropriate’ value of B for a given system. In the proposed method, the tie line power deviation is biased with regulation ‘R’ and added to frequency deviations to compose the area control errors. Exhaustive simulations and investigations have been carried out on models of interconnected power systems with the proposed method and the results have been compared with that of the conventional method. The present discussion and remarks are not for challenging the usefulness of the conventional method, however, efforts have been made to show that, the proposed method can give better results and it can have some additional advantages over the conventional method. Further, this method is quite simple to adopt. The present investigations have been kept limited to the aspects such as magnitude of excursions, transients & settling time. The proposed method is found to give satisfactory performance at various combinations of governor regulation, prevailing loading condition & simultaneous load perturbations. A simple two area thermal (non-reheat) interconnected power system is used to demonstrate the proposed method. Further investigations on the proposed method for any other aspects are open for the researchers to strengthen the scope of the present method and to explore its hidden merits.

Keywords: Interconnected Power Systems, Automatic Generation Control, Area Control Error, Area Frequency Response Characteristic, Frequency Bias