Урахування режимів експлуатації двокорпусних енергоблоків ТЕС у моделі математичного програмування оптимального завантаження електростанцій енергосистеми

Abstract

The mathematical formulas are presented which are used as additional constraints of the mathematical MILP model for optimal dispatch of power system's generation and allow adequately describe the operation of twin-boiler thermal power units both in single-boiler mode and two-boiler mode. These operation modes are widely used by the coal-fired thermal power twin-boiler units connected to the Integrated Power System of Ukraine and due to actual wider operation range allow to increase power system flexibility that is important under the big share of intermittent renewables, namely wind and solar generations. The results of calculations demonstrate that the use of additional proposed constraints allows finding more flexible operation modes of thermal power units resulting in lower curtailment levels for intermittent renewables, lower electricity generation by fossil fuel thermal power units. Notwithstanding that the operation of a twin-boiler coal-fired thermal unit in a single-boiler mode has a higher specific fuel consumption compared with a two-boiler mode the daily coal consumption is lower and that leads to the actual lower environmental impact from the fossil fuel power plants. The time of calculations using proposed MILP for optimal dispatch of power system's generation for one day (24 modeling periods or hours) is about 240 seconds and is long enough which is explained by the increase of the number of integers variables and by the dimension of the constrain matrix (the number of the rows about two times bigger the number of the columns). Those factors essentially complicate the computations with the optimization algorithm used by GLPK solver. Such essential time for the calculations requires more powerful computational equipment for the future generation mix projections task because the time for the calculations for one year could take about 24 hours. Nevertheless, for the one-day generation optimal load dispatch task the proposed model is absolutely suitable. Keywords: Integrated Power System, Load profile, thermal power plant, twin-boiler thermal unit, linear programming model, generation dispatch