工频叠加谐波电压下温度对全膜电容器绝缘介质击穿特性的影响

Influence of Temperature on the Dielectric Breakdown Characteristics of Foil-film Capacitor Under AC Superimposed Harmonic Voltage

随着非线性用电设备在工业领域的大量应用,电网中的谐波含量日渐增多,对应用于系统中的全膜电容器带来很大的危害。为了研究工频叠加谐波电压下温度对全膜电容器绝缘介质击穿特性的影响,文中以全膜电容器元件为对象,在40、55、70、85℃下分别对全膜电容器元件在工频电压、工频叠加3次谐波电压、工频叠加5次谐波电压下进行了短时击穿试验,得到了工频叠加谐波电压下温度对全膜电容器绝缘介质击穿特性的影响规律。试验结果表明,在相同电压类型下,全膜电容器绝缘介质的击穿场强随着温度的升高而下降。且在40~85℃的范围内,全膜电容器元件在同一温度下的特征击穿场强随着谐波次数的增大而降低。

With the increasing application of nonlinear electrical equipment in the industrial field,the harmonic con-tent in the power grid is gradually increasing,which brings great harm to the foil-film capacitors which is used in the system.For studying the influence of temperature on the dielectric breakdown characteristics of foil-film capacitors under AC superimposed harmonic voltages,the foil-film capacitor components are taken as the object in this paper,the short-term breakdown test under AC voltage,AC superimposed 3rd harmonic voltage,AC superimposed 5th har-monic voltage at 40,55,70,85℃are performed,respectively.The influence of temperature on the dielectric break-down characteristic of foil film capacitor under AC superimposed harmonic voltage is obtained.The test result shows that under the same type of voltage,the breakdown field strength of dielectric of the foil-film capacitors decreases with the increase of temperature.Moreover,in the range of 40~85℃,the characteristic breakdown field strength of the foil-film capacitors decreases with the increase of the number of harmonics at the same temperature.