极寒条件下均温和梯度温度对变压器油击穿特性的影响

Influences of Uniform Temperature and Gradient Temperature on Breakdown Characteristics of Transformer Oil Under Extremely Low Temperature

为探究极寒环境下实际变压器运行中绕组放热对变压器油击穿特性的影响,选择常用的45#变压器油作为研究对象,测量在极寒条件下不同温度变压器油的饱和含水量,并搭建低温环境击穿试验平台,在均温及梯度温度条件下测量变压器油的电气强度。结果表明:低温下变压器油的饱和含水量与温度之间的关系满足Arrhenius方程;低温下充分静置后,均温变压器油的电气强度在低温范围内均有一定幅度地提高,其中在电气强度极小值处即-10℃处提升最为明显,较静置前提升了51.5%;梯度温度变压器油的电气强度随温度的变化曲线和均温变压器油相似,整体呈“U”型分布,其电气强度极小值较均温变压器油并没有降低,反而略有提高,且达到电气强度极小值的温度也有所提高。

In order to study the influence of winding heat release during actual transformer operation process at extremely low temperature on the breakdown characteristics of transformer oil, the 45#transformer oil was selected as the research object, and the saturated moisture content of the transformer oil with different temperature under extremely low temperature were tested. A breakdown test platform under low temperature environment was built, and the electric strength of the transformer oil was measured under uniform temperature and gradient temperature conditions. The results show that the relationship between saturated moisture content of the transformer and temperature satisfies Arrhenius equation under low temperature. After fully standing at low temperature, the electric strength of uniform temperature transformer oil increases to a certain extent in low temperature range, and the electric strength at-10℃ increases most obvious where the electric strength is the minimum, which is 51.5% higher than that before standing. The electric strength change curve of gradient temperature transformer oil with temperature is similar to that of the uniform temperature transformer oil, showing a“U”shape distribution as a whole. The minimum electric strength of gradient temperature transformer oil does not decrease compared with that of uniform temperature transformer oil, but slightly increases, and the temperature reaching the electric strength minimum value increases.