Evaluating market power in congested power systems in real time system of Andhra Pradesh state power grid

In this paper, a linear programming algorithm is proposed for determining a measure of market concentration in congested transmission systems. The linear program uses the effects of congestors on system to derate line limits of each transmission line. The linear program uses transmission line constraints with derated line limits, generation constraints to calculate maximum SIC for group of buyers and sellers on the system. The results of the linear program provide information regarding maximum amount of power the buyers can import, as well as amount of generation each seller can provide towards the simultaneous interchange. When only few of the available sellers can participate in the maximum SIC of the buyers, the market of available generation is referred to as concentrated. Each seller´s contribution, as determined by the SIC algorithm, can be used in determining Herfindahl-Hirschman index (HHI) of concentration for the market. The resulting HHI value can then compared to government standards for HHI regarding market power in the electricity industry. Finally, sample applications of maximum SIC algorithm are examined. These examples are used to discuss the ramifications of congestion on transmission system´s concentration and the usefulness of the derated line limit solution method for determining market concentration. In this paper (128 bus system of Andhra Pradesh state power grid) a real time system is tested and the results have been presented and analyzed.