Assessment of quantitative risk indicators of electric power system operation in case of failure of the loads with responsible consumers

The article presents the basic ideas of assessment of quantitative risk indicators of electric power systems operation in case of failures of load with responsible consumers. It is proposed to use an integral risk index of functioning when evaluating the operational reliability of the EPS

Розробка нечіткого класифікатора для ранжування технічного стану силового трансформатора

The work aim is to develop a fuzzy classifier for technical condition ranking of power transformer under condition of vagueness and ambiguity diagnostic information. Methodology. The fuzzy classifier developing for technical condition ranking of power transformer was based on approach of using fuzzy set theory and optimization methods. The proposed approach for power transformer rank assessment by using a classifier was developed on the basis of Takagi-Sugeno fuzzy inference system. The input indicators choice is justified and their efficiency for classifier is evaluated by expert evaluation method. This makes it possible to formalize expert assessments regarding the development of power transformer defects. Results. The formalization of technical condition assessment of power transformer in knowledge base form, which implemented in expert system prototype for technical condition assessment, was carried out. The complex technical condition assessment for each functional unit of power transformer was determined based on expert evaluations with using the test and measurement parameters results. Originality. The considered approach to formalization of uncertainty regarding technical condition of power transformer allows building a deterministic decision-making scheme for further maintenance strategy, in which the ranking and decommissioning procedures for specific objects are implemented on the basis of objective criteria. Practical value. The proposed fuzzy classifier allows determination with a high probability degree of technical condition assessment of power transformer based on the test and measurement parameters results. Thus, an applied aspect of using the obtained scientific result is the possibility to objectively rank of power transformers park based on the identified possible defects and their development degree. This constitutes the prerequisites for determining the failure probability evaluation of power transformer at nearest observation period and emergency risk assessment in integrated electric power systems under power transformer failures.Розглянуто питання обґрунтування і розробки інтелектуальної системи для підтримки прийняття рішень щодо визначення рангу технічного стану силового трансформатора. Запропоновано підхід для встановлення рангу силового трансформатора шляхом застосування класифікатора, розробленого на базі системи нечіткого виведення Такагі – Сугено. Побудовано ієрархічні структурні схеми визначення рівнів факторів технічного стану окремих функціональних вузлів та силового трансформатора в цілому. Розроблено нечіткий класифікатор для ранжування технічного стану силового трансформатора за результатами окремих випробувань і вимірювань. Виконана адаптація нечітких моделей оцінки технічного стану шляхом навчання нечіткого класифікатора на вибірках з протоколів обстеження парку силових трансформаторів різних типів і класу напруг. Виконано комплексну оцінку технічного стану та класифікацію рангу за сукупністю контрольованих параметрів силових трансформаторів енергокомпанії

Розробка нечіткого класифікатора для ранжування технічного стану силового трансформатора

The work aim is to develop a fuzzy classifier for technical condition ranking of power transformer under condition of vagueness and ambiguity diagnostic information. Methodology. The fuzzy classifier developing for technical condition ranking of power transformer was based on approach of using fuzzy set theory and optimization methods. The proposed approach for power transformer rank assessment by using a classifier was developed on the basis of Takagi-Sugeno fuzzy inference system. The input indicators choice is justified and their efficiency for classifier is evaluated by expert evaluation method. This makes it possible to formalize expert assessments regarding the development of power transformer defects. Results. The formalization of technical condition assessment of power transformer in knowledge base form, which implemented in expert system prototype for technical condition assessment, was carried out. The complex technical condition assessment for each functional unit of power transformer was determined based on expert evaluations with using the test and measurement parameters results. Originality. The considered approach to formalization of uncertainty regarding technical condition of power transformer allows building a deterministic decision-making scheme for further maintenance strategy, in which the ranking and decommissioning procedures for specific objects are implemented on the basis of objective criteria. Practical value. The proposed fuzzy classifier allows determination with a high probability degree of technical condition assessment of power transformer based on the test and measurement parameters results. Thus, an applied aspect of using the obtained scientific result is the possibility to objectively rank of power transformers park based on the identified possible defects and their development degree. This constitutes the prerequisites for determining the failure probability evaluation of power transformer at nearest observation period and emergency risk assessment in integrated electric power systems under power transformer failures.Розглянуто питання обґрунтування і розробки інтелектуальної системи для підтримки прийняття рішень щодо визначення рангу технічного стану силового трансформатора. Запропоновано підхід для встановлення рангу силового трансформатора шляхом застосування класифікатора, розробленого на базі системи нечіткого виведення Такагі – Сугено. Побудовано ієрархічні структурні схеми визначення рівнів факторів технічного стану окремих функціональних вузлів та силового трансформатора в цілому. Розроблено нечіткий класифікатор для ранжування технічного стану силового трансформатора за результатами окремих випробувань і вимірювань. Виконана адаптація нечітких моделей оцінки технічного стану шляхом навчання нечіткого класифікатора на вибірках з протоколів обстеження парку силових трансформаторів різних типів і класу напруг. Виконано комплексну оцінку технічного стану та класифікацію рангу за сукупністю контрольованих параметрів силових трансформаторів енергокомпанії

Development of a Mathematical Model for Cost Distribution of Maintenance and Repair of Electrical Equipment

The research is devoted to the development of a model for cost distribution of maintenance and repair of electrical equipment when making decisions on the management of the electric power system state. The decrease in the reliability of electric power system operation, caused by the objectively existing aging of electrical equipment, requires consideration of equipment significance when planning the maintenance and repair. For this purpose, it is proposed to use the theory of fuzzy sets, Saati's method and Boolean programming method. The result of solving the optimization problem of multicriteria analysis is a vector of the best alternatives, built on the principle of dominance. The developed algorithm of complex simulation of the electric power system state and cost distribution of maintenance and repair for making decisions on the determination of priority of electrical equipment out of service allows for effective decision­making. The results of probabilistic and statistical simulation of electric power system states using the Monte Carlo method allow us to take into account the probabilistic nature of emergency situations in the electric power system when determining its weakest elements that require priority replacement. The advantage of the proposed approach is taking into account the technical condition of electrical equipment for risk assessment of the electric power system emergency situation. A comparative analysis of ranking results of electrical equipment based on the emergency risk assessment of the electric power system confirmed the high efficiency of the planning of electric power system states when solving the problems of preventive control. The developed model will be used for further research and development of the algorithm for making effective decisions regarding the operation strategy of the electrical equipment and preventive control of the subsystem operation of the electric power system. The obtained results of complex simulation of the electric power system state and technical condition of the electrical equipment give grounds to assert the possibility of software implementation of operation risk analysis of the electric power system for power supply companie