计及环境条件的电力变压器热路模型及其应用

Thermal Circuit Model of the Transformer Considering Environment Factors and Its Application

变压器内部温度的获取是评估其运行状态及性能的重要手段,该温度除了与变压器运行条件有关外,还直接受环境温度、风及日照等环境因素的影响。在分析具有内热源的箱体热路模型以及变压器热量传递过程的基础上,论文首先对所处环境条件不发生变化时变压器的理想热路模型进行了研究,构建了综合考虑环境温度、日照辐射、自然风速等环境因素以及运行工况的变压器热路模型;然后给出了计算变压器热点和顶油温度的热路模型分析方法,计算了非额定运行状态下运行变压器的顶油温度及热点温度,并与实际运行变压器内部温度的实测值进行了对比。结果表明：基于所提出的变压器热路模型计算得到的热点温度变化规律与实测温度相近,最大计算误差仅为2.3℃,即所提模型可有效反映变压器运行工况及环境因素对内部温度造成的影响。论文研究可为电力变压器运行状态及性能的评估提供参考。

Acquisition of the internal temperature of a transformer is an important method to evaluate its operating state and performance. Besides, the operating condition of a transformer, the environmental temperature, wind, sunlight and other environmental parameters can also influence its internal temperature directly. By analyzing the thermal circuit model of transformer tank with inner heat source and the heat transmission process of the transformer, we investigated the ideal thermal circuit model of the transformer when the environmental conditions were stable. Moreover, we constructed a thermal circuit model of the transformer after taking the environmental temperature, solar radiation, natural wind velocity and other environmental parameters and operating states into consideration, and introduced the analysis method of thermal circuit model for the calculation of the hot spot and the top oil temperature. Furthermore, we calculated the top oil temperature and hot spot temperature of the transformer under non-rating operating state, and compared them with the measured values of the internal temperature for the actual transformer during its operating process. The results show that temperature calculated by the constructed thermal circuit model is close to the variation of the measured temperature, the maxmum calculation error is only 2.3 ℃, and the constructed thermal circuit model can effectively reflect the influences of the operating state of the transformer and environmental parameters on the internal temperature. The research results can provide a reference for evaluation of the operating state and performance of power transformers.