一起变压器铁芯油道堵塞导致过热的缺陷分析与治理

Analysis and Treatment on Transformer Core Overheating Caused by Blockage of Oil Channel

文中分析了一起220 kV变压器因铁芯油道堵塞造成的发热缺陷。通过油中溶解气体分析判断变压器内部存在中温过热问题,内部绝缘存在劣化隐患。返厂解体后,发现铁芯柱内部、铁芯柱与低压线圈内纸筒之间的油隙较小以及部分硅钢片毛刺较大,导致铁芯内部和外表面油流不畅、铁芯散热能力较低,造成铁芯、夹件绝缘材质老化。利用仿真建模方法,发现拉板温升异常。对铁芯柱内部油道绝缘、铁芯结构、散热器进行改进,提高了铁芯散热性能。

A heating defect caused by a blocked oil channel of 220 kV transformer core is analyzed. The dissolved gas-in-oil analysis determines that there is a medium-temperature overheating problem inside the transformer and a potential risk of deterioration of the internal insulation. After the disassembling in the factory, it is found that the oil gaps inside core limbs and between core limb and paper cylinder in low-voltage coil are small, and some of silicon steel pieces have large burrs, so it causes the poor oil flow on the inner and outer surfaces of core and the low heat dissipation capacity of core, which causes the aging of insulation materials of core and clamps. Using the simulation modeling method, abnormal temperature rise of pulling plate is found.The improvement for internal oil channel insulation, core structure and radiator of core limb are carried out, thus to improve the heat dissipation performance of the core.