Method for Creating Mathematical Models of Heating Nuclear Power Units of Power Plants for Optimization Studies of Autonomous Electric Power Systems

The authors present a two-stage method for creating mathematical models of cogeneration nuclear power units for optimization studies of autonomous electric power systems. The first stage of the methodology includes the development of a detailed model of a nuclear power unit, which provides a satisfactory accuracy of the description of physical and technological processes, as well as optimization calculations of operating modes. At the second stage, the energy dependencies are built based on the results of optimization calculations of the first stage. Energy dependencies define the boundaries of the region of feasible solutions in the form of polynomials. A simplified mathematical model of a nuclear power unit for optimization studies of autonomous EPS is created using polynomials. To solve the problem of finding a polynomial, a two-step approach is proposed. At the first step, the polynomial coefficients are selected such that the minimum of the maximum value of the modulus of the difference between the function determined using the polynomial and the function determined using the detailed model of the power unit is reached. At the second step, the deviation modules are limited to the value found at the first step, and the sum of the deviation modules is minimized at all points. The two-stage technique developed by the authors is demonstrated on the example of a cogeneration nuclear power unit, which is supposed to be operated in the climatic conditions of the Far North.