谐波电流扰动下配电变压器损耗计算与绝缘寿命损失评估

针对谐波电流引起配电变压器损耗增加、热老化加速、绝缘寿命下降的问题,提出了一种计算谐波电流扰动下变压器空载损耗的方法。通过对Yyn0和Dyn11联结的配电变压器在谐波电流扰动下的杂散损耗分析,改进了基于谐波损耗因子的变压器负载损耗计算方法,修正了热点温度计算模型。以98℃为变压器热点温度基准值,利用6℃准则修正了IEEE C57.91中的绝缘纸相对老化因子计算方法。计算及试验结果表明:变压器损耗随谐波电流畸变率增大有较大增加,造成变压器绝缘系统寿命损失,缩短变压器运行寿命。

Calculation Distribution Transformer Loss and Insulation Life under Harmonic Currents

The harmonic current will cause the loss of the distribution transformer,the acceleration of the thermal aging and the decrease of the insulation life.A method for calculating transformer no-load loss under harmonic current disturbance is proposed in this paper.The distribution transformers of Yyn0 and Dynl 1 connection of the stray loss in harmonic current disturbance have been analyzed.So the calculation method of transformer load loss based on harmonic loss factor is improved,.and hot spot temperature calculation model is corrected.The calculation method of relative aging factor of insulating paper in IEEE C57.91 was modified by using 6 ℃ criterion,the reference value of transformer hot spot temperature at 98 ℃.The results of calculation and experiment show that the transformer loss increases with the increase of the harmonic current distortion rate,so the life loss of transformer insulation system is shortened,and the service life of transformer is shortened.