Determining the maximally permissible values for the indicators of insulation of sealed entrance bushings with a voltage of 110 kV using the method of minimal risk
Journal Title: Восточно-Европейский журнал передовых технологий - Year 2018, Vol 5, Issue 8
Abstract
<p>A method for determining the maximally permissible values for the indicators of insulation of high-voltage oilfilled entrance bushings that ensure the minimal risk value has been proposed. The proposed method differs in that the maximally permissible values for indicators are determined by minimizing the function of average risk, using the Newton’s method, taking into consideration the actual operating conditions of equipment, which makes it possible to improve the operational reliability of entrance bushings.</p><p>We have derived an expression to determine the average risk with respect to the distribution law of indicators for the insulation of high-voltage entrance bushings (by Weibull), the minimization of which makes it possible to determine the maximally permissible values for the indicators, taking into consideration the duration of their operation, the values of load currents, the grade of a transformer oil, and other factors.</p><p>A comparative analysis was performed for risk values, which are accompanied by applying the maximally permissible values for indicators that are regulated in Ukraine, with the maximally permissible values for indicators, which were obtained by using different methods. The analysis revealed that the minimal risk value is ensured by the maximally permissible values for indicators, which are obtained by applying the method of minimal risk, taking into consideration the operating conditions for entrance bushings. We have performed an analysis of impact of the values for probabilities of the proper-functioning and faulty state of entrance bushings, the cost of incorrect decisions, as well as the value for a scale parameter and a shape parameter in the Weibull distribution, on the maximally permissible values for the indicators of insulation of high-voltage oil-filled entrance bushings in an airtight structure. It was established that an increase in the probability of a defect and its conditional cost, as well as prolonging the operation duration of entrance bushings and their loading, leads to a decrease in the maximally permissible values for the indicators. It has been proven that the maximally permissible values for the indicators of insulation of high-voltage entrance bushings, which ensure the minimal economic loss, are not constant. In order to practically implement the method of minimal risk during operation, it has been proposed to apply the likelihood ratios, which make it possible to diagnose the state of high-voltage entrance bushings at a minimal risk, but without determining the maximally permissible values for the indicators.</p>
Authors and Affiliations
Оleg Shutenko, Alexandra Zagaynova, Galina Serdyukova
Keywords
Related Articles
- EP ID EP528200
- DOI 10.15587/1729-4061.2018.142185
- Views 59
- Downloads 0
Research of a microwave radiometer for monitoring of internal temperature of biological tissues
<p>Currently, there is growing interest among specialists in the use of non-invasive dose-free technologies for diagnosis and monitoring treatment of various diseases. Microwave radiometry enables non-invasive detection...
Determining the rational compositions of low-strength concretes
<p>The paper reports regularities in the influence of the amount of waste from iron ore enrichment at a rational composition of grain components on strength of concretes with a minimal cement consumption. Low-strength co...
The development of methods for determining vibration stochastic fields of technological complexes
<p>The force effects occurring in technological complexes have been studied on the basis of the analysis of technical diagnostics system. Due to the distinction between deterministic and random force effects, there have...
Development of a theoretical model for the intensification of technological processes for manufacturing dairy products
<p>A dependence is established between the amount and forms of calcium in milk and its technological purpose. It is proven that a controlled reduction in the content of calcium in milk (specifically, its ionic form) incr...
Bitwise method for the binary-coded operands conversion based on mathematical logic
<p>This paper addresses the development and examination of the unconventional highly-efficient bitwise tuple-tabular logical-reverse method, underlying the construction of precision models of computational information co...