Hydro Generating Units Maintenance Scheduling Using Benders Decomposition

Preventive generating units maintenance scheduling is among the most vital decisions which electricity generating companies have to make. Effective generating units maintenance helps reduce the forced outage rates. Therefore, rigorous technical restrictions have to be respected by all means. Since the economical factor, i.e. profit generation, was not the prime driver in investments, the maintenance in vertically integrated power systems was carried out thoroughly and most of the elements of the power system were over-dimensioned. These proper maintenance procedures resulted in extremely rare failures in the vertically integrated power system operation. After the implementation of the electricity market, economic drive grew stronger and private companies wanted to avoid any unnecessary investments in order to increase their profit margin. The maintenance enforcement expenses have two aspects. The first one is the cost of the maintenance itself, which includes the newly installed components, specialized teams hiring, etc. The other part of the expenses is the missed income due to undelivered electricity. Therefore, the maintenance has to be performed in the shortest period possible. Other factors, such as electricity and fuel prices also have to be taken into consideration. Since the hydro power plant's owners do not have to buy fuel, their objective is to predict the water inflows and schedule the maintenance in low river inflow period.