九江三期1号主变出厂冲击试验失败原因及处理

The Analysis Causes and Countermeasures for the Failing Impulse shop Test on No.1 Main Transformer Jiujang Third Project

九江三期发电工程采用两台 4 4 5MVA主变压器 ,分别将两台 35 0MW发电机的 2 3kV出口电压升高到 2 2 0kV接入升压站。其中 1号主变压器在制造厂进行冲击试验时 ,两相高压绕组发生绝缘击穿 ,未通过冲击试验。针对该变压器的此次冲击试验造成的损坏部位及形成原因进行分析 ,找出变压器的绝缘设计和制造工艺上的缺陷 ,提出处理措施 ;另一方面通过比较此次雷电冲击电压与操作冲击电压对变压器绝缘损坏的部位的不同 。

There are two 445MVA Main Transformers for jiujiang Phase Ⅲ power project, which separately increases the outlet voltage of two 350MW Generators from 23kV to 220kV matched with the swicthyard. Main transformer No.1 failed in the impulse shop test, with two phases of high voltage windings broken down. This article is intended to find out the faults of the design and manufacturing based on the analysis of the tests and inspection results of the main transformer, and propose countermeasure. In addition, the different effectiveness of the two impulse tests on the transformer can be judged by comparing its varying portions damaged by the lightning impulse test and the switching impulse test.