电力变压器绕组热点温度软测量技术研究

Research of Soft-measurement Technology of the Transformer Winding Hot Spot Temperature

摘要:

电力变压器是发电系统中最重要的设备之一,变压器绕组热点温度是影响绕组绝缘寿命和变压器过载运行的主要原因；传统的热电类比模型忽略了变压器各器件之间的温度差及其在运行中可能出现的冷却系统运行方式的改变,实际应用中存在一定的误差；因此,在热电类比模型和IEEE导则推荐的热点温升模型基础之上,提出了一种软测量模型；该模型充分考虑了运行中不同的变压器实际操作情况的不同,添加了辅助变量(油黏度、冷却风扇运行个数等)对主导变量进行计算和优化；模型的有效性通过与某ONAN自然油循环冷却方式的变压器的实际温升数据对比得到了验证,其仿真结果相比于IEEE导则推荐的热点温升模型,具有更加精确的预测能力和更高的暂态过程准确性。

Abstract:

Power transformer is one of the most important equipment in the power system,the hot spot temperature of transformer winding is the main reason for the winding insulation life and the power transformer overloading capability. Traditional thermoelectricity analogy model ignores the temperature difference between transformer devices and its possible mode change of cooling system in the operation, some errors will be caused by these reasons in the practical application. Therefore, based on thermoelectricity analogy model and the GB/T 15164-1994 loading guide method, a soft measurement model is put forward. The model fully considers different transformers’ operation situations and adds auxiliary variables (oil viscosity, the number of cooling fans, etc.) to figure out and optimize the leading variables. The model is proved to be effective by comparing the calculation results of the measured data obtained from a natural oil circulation cooling ONAN transformer. Finally, the simulation results from this model are compared with IEEE guide method results. The comparison proves the model presented is more adequate and has higher accuracy in transient process. 