Анализ режимов работы сухих силовых трансформаторов напряжением 10(6)/0,4 кВ

Abstract

The calculation of the most heated winding point temperature and the rate of thermal aging of the insulation for a dry power transformer at different parameters of the electrical load and different ambient temperature during the year is performed. As parameters of the electric load are considered: harmonic composition of the current (the coefficients of the h-th harmonic component), the proportion of power users with a nonlinear current-voltage characteristic in the full load power and fraction of full power users with a nonlinear current-voltage characteristic in the total of the power transformer. The dependence of the rate of insulation thermal aging on the ambient temperature is obtained for different load parameters and load factors of power transformers. An expression is obtained for determining the coefficient of the permissible load reduction of a power transformer when the ambient temperature exceeds the value of 20°C. The necessity to take into account the influence of ambient temperature when choosing the power of dry power transformers that are supposed to operate in full redundancy mode or with high load factor values ( ≥ 0.8 ) in normal mode is confirmed. To avoid exceeding the nominal value of the thermal aging rate of insulation windings of dry power transformers it is necessary to determine the design power of power transformers using the coefficient of the permissible load reduction under the influence of higher harmonic components of the current and the coefficient of the permissible load reduction under the influence of ambient temperature.