A Method for Condition Evaluation of CVT Based on Online Error Distribution

Insulation test is the mainly technical means on CVT's condition evaluation. However, insulation test is usually performed offline. The total work is so heavy that the interval is too long. For the reason, the paper proposes a method to evaluate the insulation performance based on online error distribution. It is realized by error group measurement. By analyzing the impact of each component of the CVT on the error, and the data get by error group measuring device, the insulation status of CVT could be evaluated. To verify the effectiveness of the method, a test was experimented at a $220\mathrm {k}\mathrm {V}$ substation. The result shows that the method is easy to operate, safe for devices and people, and clear for judgment. By using the method, the maintenance plan only needs to focus on the suspected CVT. In this way, the maintenance work is reduced and the efficiency is improved.