Background. When solving problems of forecasting technical and economic performance, planning, and enhancement of the operating modes of power units, their mathematical models are required that exhibit acceptable adequacy across the entire adjustment range of equipment load. Development of mathematical models based on verification of thermal calculations of power unit components and heat-and-mass balance calculation is not only labor-intensive but also, in most cases, does not allow achieving the required accuracy when describing real time modes of equipment operation. In the case of using specialized software to develop mathematical models, these shortcomings can be partially overcome. However, such models are difficult to use when solving real-time optimization problems and in cases where model integration into a higher-level software and hardware system is required. Therefore, in practical work, mathematical models based on standard energy characteristics of equipment are most often used. To ensure the required accuracy of such models, it is necessary to develop appropriate methods for their identification based on technical accounting and control data of the operating power plant.
Materials and methods. The mathematical model of the CCGT-120 power unit is developed based on the standard energy characteristics of the equipment. The adjustments to the main and intermediate thermal efficiency indicators have been determined using multiple linear regression based on data of operation observation. Model identification is further conducted based on the results of calculating the components of the thermal efficiency reserve.
Results. A mathematical model of the CCGT-120 power unit has been developed, based on the standard energy characteristics of the equipment. To ensure the required accuracy of the calculation results, a two-level identification of the CCGT unit component submodels is used, using operational observation data. The developed model has been tested on an operating power unit.
Conclusions. The results of testing the developed mathematical model confirm its applicability for forecasting technical and economic performance with acceptable accuracy. The proposed approach to development of mathematical models can be recommended when developing software applications designed for planning and optimizing the operating modes of combined-cycle gas turbines at thermal power plants.