It becomes more and more obvious that focusing solely on economic efficiency is not a good strategy for business development. Moreover, a quantitative assessment of the integral operation indicators, including complex indicators of efficiency, environmental performance and safety, can help to protect a business against possible bankruptcy [1]. In the electric power industry, this is reflected in the modified concept of operational efficiency (OE). OE is not only the usual economic efficiency, but also operational reliability and safety. There is a good reason for such modification of the concept. In electric power systems (EPS), the actual service life of about 60% of the main equipment, devices and installations exceeds the rated value. We shall refer to such equipment as “overage facilities” (OF). The failure of such OF is the main cause of unacceptable system emergencies. During the rated service life of EPS, only a quantitative assessment of operational economic efficiency is performed. Operational reliability and safety (for example, the average monthly values) are not calculated, since they are guaranteed by the manufacturer. However, after the warranty period is over, operators still do not evaluate complex indicators of operational reliability and safety, since there is no methodology for their assessment. Moreover, it is necessary to be able to calculate the integral OE indicators which reflect the actual values of economic efficiency, operational reliability and safety. It can significantly reduce the risk of mistakes when choosing the methods for organizing operation, maintenance and repair. Then, decisions will be made based on comparing these integral indicators. The random nature of changes in technical and economic indicators (TEI) is determined by the random nature of changes in the integral OE indicators. The article presents new methods and algorithms for determining the feasibility of classifying the integral OE indicators of OF.
Improving the operational efficiency (OE) of thermal power plants is one of the most important problems of electric power systems (EPS). According to modern concepts, efficiency is the simultaneous consideration of three properties of objects, viz. economy, reliability and safety. The methodology of their joint assessment assumes that the service life of the main equipment does not exceed the standard value, but this condition is now met by less than half of the production enterprises of a lot of EPS. In order to increase OE, it is necessary, first of all, to learn how to objectively compare the performance of objects both of the same type – in a given time interval, and unique ones – in adjacent intervals. Existing methods for calculating integrated performance indicators do not fully take into account the random nature of technical and economic indicators (TEI). The article presents a new method for comparing the OE of EPS objects, the essence of which is to switch from joint consideration of TEI to analysis of their relative changes in comparison with the factory default value (nominal value). Relative values of indicators characterize the amount of wear or residual life. In this case, for example, the arithmetic mean of the relative values of the TEI determines the average wear of the object. This physical representation enlivens integral indicators, and their comparison and ranking ceases to be science-intensive. It is proposed to take into account also the degree of variation of relative deviations (wear), which is adequate to the object’s misalignment. It manifests itself in a significant change (deterioration) of one or (less often) two relative values of the TEI in the calculated time interval (month) and is characterized by such statistical indicators as the geometric mean and the coefficient of variation of relative deviations. Herewith, if the arithmetic mean value of the object’s wear is restored during major repairs, then the misalignment is eliminated much faster – during current repairs. A necessary condition for the feasibility of using these or those integral indicators is their functional and statistical independence. The results of the studies performed using the simulation method made it possible to establish that the smallest correlation occurs between the integral indicator calculated as the arithmetic mean of random variables and the integral indicator calculated as the coefficient of variation of the same random variables. Comparison of correlation fields clearly confirms these conclusions.
One of the basic problems of electric power systems is the absence of normative documents regulating the operation, maintenance and repair of the capital equipment, the service life of which exceeds the normative value. We shall name them «old equipment» (OE). The essence of the difficulties to be overcome is reduced to the absence of methodologies for quantitative estimation of operational reliability and safety of OE, with the subsequent comparative analysis of OE. Considering the science intensity, cumbersomeness and labour intensity of solving this problem, the necessity of development of the relevant automated systems becomes indisputable. In this article, some features are considered of an estimation of an integral indicator and comparative analysis of unique facilities. Here, unique facilities mean those, which have no analogues in terms of the set combination of varieties of significant attributes. The methodological foundations of the synthesis of integral indicators are considered: ensuring the infallibility of the information base; requirements to evaluations of integral indicators; providing the physical essence of the integral indicator; possible types of integral indicators; the comparison of integral indicators of operational efficiency in the framework of the theory of testing statistical hypotheses for one-dimensional random variables is associated with a high risk of erroneous decisions; the assessment of the critical values of the integral indicator is carried out on the basis of simulation modeling within the framework of the fiducial approach.The development of automated systems for collecting and formalizing data on the technical condition of OE, the automated analysis and synthesis of these data, performing standardization of TEI, evaluating integral indicators and some results of comparative analysis, preparing operational recommendations to improve work efficiency, developing appropriate methodological guidelines, indicate the possibility of an objective assessment of the operational efficiency of OE and a decrease in the risk of unacceptable consequences. For an illustration of recommended methods and algorithms, technical and economic parameters of power units with SGI-400 are used.
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