Analysis of Operating Conditions and Modes Influence on Technical State of Main Insulation of High-Voltage Bushings of Different Design

Abstract

The results of the analysis of the influence of operating conditions and design of high-voltage bushings on the values of dielectric loss tangent of high-voltage bushing basic insulation. For analysis a model of two-factor cross-sectional dispersion analysis, which allows to simultaneously evaluate the influence of two factors and evaluate the effect of their interaction is used. In the model used, it is assumed that the effects of changes in the levels of factors are non-additive, that is, the difference in mathematical expectations between any two levels of one factor is not the same for any levels of the other. Testing the hypothesis of the significance of the influence of factors and their interactions is performed using the Fisher criterion. This method was implemented in the form of the author' program «two-factor dispersion analysis». The results of periodic monitoring of the state of high-voltage bushings of 110, 220 and 330 kV with different types of insulation were used as initial data. Using the model of two-factor cross-sectional dispersion analysis, it was found that the aging intensity of the main insulation of bushings is influenced by both the operating conditions and the design features of the bushings. Maximum permissible values of diagnostic indicators of high-voltage bushings should be normalized taking into account such factors as nominal voltage, type of protection and type of insulation, load of bushings and the composition of consumers. Since, based on the analysis performed, it was established that these factors have a significant impact on the values of diagnostic indicators of insulation of bushings. According to the results of the analysis performed, it was established that such factors as the type of bushing and phase do not have a significant effect on the change in the values of diagnostic indicators of high-voltage bushings, and, therefore, they can be ignored when determining the maximum permissible values of the indicators. References 24, tables 7, figures 14.Key words: high-voltage bushing, insulation, two-factor cross-sectional dispersion analysis, insulation indicators, dielectric loss tangent. Бібл. 24, табл. 7, рис. 14. Ключові слова: високовольтний ввід, ізоляція, двохфакторний перехресний дисперсійний аналіз, показники ізоляції, тангенс кута діелектричних втрат. 110, 220 и 330 кВ с изоляцией разного типа. Используя модель двухфакторного перекрестного дисперсионного анализа, установлено, что на интенсивность старения основной изоляции вводов оказывают влияние как условия эксплуатации, так и особенности конструктивного исполнения вводов. Новые положения, по сравнению с известными решениями, состоят в том, что предельно допустимые значения диагностических признаков высоковольтных вводов следует нормировать с учетом таких факторов, как номинальное напряжение, тип защиты и тип изоляции, загрузка вводов и состав потребителей. Полученные результаты могут быть алгоритмически реализованы в виде отдельного модуля информационно-аналитической системы (ИАС) для диагностики состо...