基于热路模型的变压器内部温升计算方法研究

Study on Calculation Method for Internal Temperature Rise of Transformer Based on Thermal Circuit Model

为解决油浸式电力变压器内部温升在运行中难以获取的难题,针对运行工况及环境因素,提出了一种计算变压器实时损耗和散热热阻的方法,在此基础上建立了基于平均油温计算变压器顶油及热点温升的热路模型,分别对3台变压器的内部温度进行了计算,并与实测温度数据进行了比对分析。结果表明:计算得到的顶油温升最大误差不超过3 K,热点温升最大误差为4.3 K,均在工程应用误差范围内,验证了新建立的热路模型的准确性,可应用于现场实际运行变压器内部温度的预测。

To solve the problem that the internal temperature rise of oil-immersed power transformer is difficult to obtain during operation, we proposed a method to calculate real-time loss and thermal resis-tance of heat dissipation according to operation condition and environmental factors. And a thermal cir-cuit model to calculate top-oil and hot-spot temperature rise based on the average oil temperature was built. The internal temperature of three transformers were calculated and then compared with actual mea-surement data. The results show that the maximum error of top-oil temperature rise is less than 3 K, and the maximum error of hot-spot temperature rise is 4.3 K, which is in the error range of engineering appli-cation. The new thermal circuit model is verified veracity and could be applied to forecast the internal temperature of actual transformer in service.