Mathematical model of variation of output operational characteristics of steam turbines of thermal power plants

In this article we have studied the statistic materials for failures and malfunctions that aff ect the performance of heat power installations. This is a qualitative analysis and quantitative assessment of indicators of reliability of different turbine types. In the paper, there is presented a mathematical model of variation for output characteristics of a turbine depending on the number of failures observed in the course of operation. The mathematical model is based on methods of mathematical statistics, the probability theory and methods of matrix calculus. The novelty of this model lies in the fact that it allows predicting variation of control parameters and the output characteristic in an explicit form. The parameters that can be assumed as such characteristics are: average load, heat generation and electric power generation, running time, amount of time spent on emergency repair, number of staff participating in repair, cost of repair, income from sales of thermal and electric energy, availability quotient, probability of no-failure operation, etc. Based on the statistical data obtained at operation of steam turbines, quality and quantitative assessments of reliability indicators has been presented. Specific measures are suggested for elimination of causes of failures of components of turbines and turbine equipment. These are the failures of turbine blades caused by exhaustion of service life and extreme fatigue of metal that are accounted for the largest number of cases of damage and failure of turbines. Statistics of failures of bearings are affected by both internal and external factors of technical and operational nature. Damage of bearings and parts of rotors most often leads to unscheduled shutdown and repair of the turbine. The most common failures are those of the main oil pump and oil pipelines. According to statistical data, it is possible to develop appropriate measures for improvement of output characteristics. This is a so-called a model of management of output characteristic. For the purpose of management of the output characteristic, a probabilistic model taking into account the operating influences in an explicit form has been offered. A specific example of variation of turbines' output characteristics over a long-term period of operation has been given.

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