Methodology for selecting the frequency and duration of scheduled repairs for main heat and power plants units considering the peculiarities of combined energy generation and participation in the day-ahead market

The study is aimed at developing a methodology for assessing the impact of schedule and volume of planned repair work - as well as reliability indicators of the main generating units - at combined heat and power plants on the efficiency and reliability of their operation. The described methodology is complemented by the creation of a software and computing complex for its implementation. For the development of the software and computing complex, mathematical modelling and optimisation methods were used. These were then implemented by the software and "System of Computerised Program Construction" computing complex created earlier by the employees of the Melentiev Energy Systems Institute Siberian Branch of the Russian Academy of Sciences. Optimisation calculations were carried out according to the criterion of maximum possible profit from the sale of electricity on the day-ahead market taking into account the optimal unit commitment according to the algorithm for the formation of optimisation tasks to minimise non-delivered energy production. By means of the software computing complex for selecting the frequency and duration of scheduled repairs, two calculation options were carried out differing in the calendar periods of operation between two consecutive complete, intermediate and current repairs. Under the operating mode of the CHP plant according to the option with longer periods of operation between repairs, the possible profit of the power plant from the sale of electricity in the day-ahead market is determined to be 169.8 million RUB, which is 1.2% more than the profit under the operation mode with shorter repairing periods. The losses from the non-delivered electricity for the adopted options were determined to be 10.5 and 10.64 million RUB, respectively, while, for the non-delivered heat energy, the losses comprised 37.3 and 37.7 million RUB, respectively. For the considered options, the difference in the amount of losses from non-delivered electricity and heat energy was 1.3 and 1%, respectively. The economic assessment of losses from possible emergency interruptions in power supply to consumers estimated on the example of an industrial CHP plant supports a conclusion concerning the applicability of the developed methodology for selecting the schedule and volume of planned repair work at the main generating units.

thermal power equipment, mathematical model of a heat and power plant, optimization studies, schedules and volumes of planned equipment repairs, reliability of a heat and power plant operation, efficiency of a heat and power plant operation