This article describes the rationale for the development of a mathematical model of the thermal scheme of Vladivostok thermal power plant. Four types of turbines are installed at this plant, boiler units operate on coal and natural gas. This makes it difficult to effective load distribution between the turbine units. Application of simplified dependencies, built on the basis of the reporting data, allows to analyse the correctness of the load distribution between the units. The article provides an example of comparing the actual parameters of the plant and calculating based on the  simplified characteristics of turbines. This example showing the loss of fuel equivalent from non-optimal load distribution. However, the use of such simplified characteristics has several shortcomings. These shortcomings do not allow using this as a universal method. There is a need to create a full-fledged mathematical model of thermal power plants. The model is developing on the basis of the Boiler Designer software package. The program has a modular structure and allows you to create mathematical models of each unit of equipment, and then, through the purpose of connections, assemble the thermal scheme of the station. This approach is actual for cross-linked heat and power plants, since it allows us to evaluate the efficiency of thermal scheme connections, and not just the operation of the equipment itself. The article provides a simplified model of the station, its advantages and disadvantages.