Optimum generation scheduling with purchase of power from market and grid

For every state utility in India, along with state owned generation there are two major sources of power available to fulfill the load demand. They are, Central Govt owned generation i.e. central sector generation and power purchased from power trading market. For optimum scheduling, additional sources of power need to be incorporated in the generation scheduling algorithm, along with their individual cost functions. In India, power available from central sector generators is charged through frequency dependant tariff called availability based tariff (ABT) and power available at market is charged at market clearing price (MCP). The incorporation of frequency dependant central sector generation as `grid generator' is reported earlier. In the present work, the feasibility of incorporating power available at market as `market generation' in preparing a day ahead schedule is established. The optimum scheduling problem becomes distributing load amongst internal generators, central sector generator and power purchased from market, with appropriate cost functions so as to minimize cost of generation. The modified generation scheduling algorithm with grid generator and market generator is implemented on a 26 Bus Test System. The results show that it is possible to simulate market as an additional generator. The market support, so incorporated shows that there is lot of saving in system cost if purchase of power from market is considered during scheduling process.