热老化下换流变压器内油纸绝缘组合理化和电气特性研究

Study on the physicochemical and electrical properties of oil-paper insulation combination by thermal ageing

换流变压器是特高压直流输电系统十分重要的电力设备,其内部的油纸绝缘水平和运行状况直接关系到电力系统的安全与稳定。研究换流变压器内部油纸绝缘在热老化下的理化特性,将有助于提升换流变压器的油纸绝缘水平。选取了特高压换流变压器可能采用的绝缘油纸作为研究对象,对四种不同油纸组合展开加速热老化试验,测量并分析试验过程中绝缘纸聚合度、油中水分含量、油中酸值、绝缘油运动黏度、热稳定性、相对介电常数和介质损耗因数的变化情况,给出油纸绝缘理化和电气特性的理论参考。

The converter transformer is the key electrical equipment of UHVDC system. The safety and stability of power system is directly related to the level of internal oil-paper insulation and operating conditions. It is helpful for improving the level of oil-paper insulation of the converter transformer to study the physicochemical properties of the internal oil-paper insulation within thermal aging. The insulating oil and paper that may be used in the converter transformer are taken as the research objects. Accelerated thermal ageing tests with four different groups of oilpaper is accomplished via analyzing the degree of polymerization(DP) of the insulation paper and the water content, acid value, kinematic viscosity and thermal stability, relative permittivity and dielectric loss factor. Ultimately, the results provide a theoretical reference for the physicochemical and electrical properties of the oil-paper insulation.