CAJ | 학술논문

换流变压器绝缘材料电导率受电场强度、温度和压力等因素影响,即呈现非线性特性。为了考查非线性对换流变压器极性反转电场分布的影响,针对电导率对电场强度的非线性,对绝缘纸板和油的电导率非线性特性进行了数值拟合,并用于分析1台±500kV换流变压器的非线性极性反转电场。线性和非线性媒质条件下的计算结果表明,考虑1min极性反转的过程时,线性媒质中反转完成时刻的油中最大电场强度值同瞬间完成极性反转的数值结果几乎相同,而非线性条件下反转完成时刻的油中最大电场强度值要比瞬间完成极性反转的数值结果小50%。针对这一现象,进一步对非线性条件下空间电荷加速重新分布的过程进行了分析。
환류변압기절연재료전도솔수전장강도、온도화압력등인소영향,즉정현비선성특성。위료고사비선성대환류변압기겁성반전전장분포적영향,침대전도솔대전장강도적비선성,대절연지판화유적전도솔비선성특성진행료수치의합,병용우분석1태±500kV환류변압기적비선성겁성반전전장。선성화비선성매질조건하적계산결과표명,고필1min겁성반전적과정시,선성매질중반전완성시각적유중최대전장강도치동순간완성겁성반전적수치결과궤호상동,이비선성조건하반전완성시각적유중최대전장강도치요비순간완성겁성반전적수치결과소50%。침대저일현상,진일보대비선성조건하공간전하가속중신분포적과정진행료분석。
The conductivity of insulation oil and paper of the converter transformer is influenced by electric field strength,temperature and pressure etc.In order to study the influence of electric dependent conductivity on electric field distributions,the nonlinear characteristics between electric field strength and conductivity of the oil is fitted by an exponential curve.Using the new nonlinear curve,the transient nonlinear electric field of a ±500 kV converter transformer under PR（polarity reversal） voltage is calculated by the C-N（Crank-Nicolson） method.The numerical results under linear and nonlinear conditions show that,when we consider the 1 minutes duration of the PR process,the linear maximum electric field strengths at the end of the ramp voltage of the PR are almost equal to the results under the step voltage,while the nonlinear maximum electric field strengths at the end of the ramp voltage of the PR are about 50 percent less than the results under the step voltage.The phenomena of the less value under the nonlinear condition are explained by the acceleration of the space charges under the electric dependent conductivity.