How to prevent explosion of miniature current transformer

To prevent the explosion of the miniature current transformer, first of all, when the test value is abnormal, the cause should be found out. When the dielectric loss factor tg value measured before and during operation is abnormal, the tgδ and temperature should be comprehensively analyzed. When the change or test voltage rises from 10kv to Um/root 3, when the increment of tgδ exceeds ±0.3%, the operation should be stopped. When the chromatographic analysis results are abnormal, follow-up analysis should be carried out to investigate the growth trend. If the data grows rapidly, attention should be paid. Nip accidents in the bud.

To prevent the explosion of the miniature current transformer, then, pay attention to ensure the normal operation of the busbar differential protection. In order to avoid expanding the scope of the accident when a breakdown accident occurs at the bottom of the capacitor core of the miniature current transformer, it should be noted that the installation direction of the primary terminal L1 and L2 and the polarity connection method of the secondary winding should be correct to ensure the normal busbar differential protection. put into service.

To prevent the explosion of the miniature current transformer, pay attention to checking the short-circuit current. According to the development of the power grid, pay attention to checking the short-circuit current at the location where the current transformer is located. When it exceeds the dynamic thermal stable current value on the nameplate of the transformer, it is necessary to arrange and calculate it in time. replace.

The last step to prevent the explosion of miniature current transformers should be on-line monitoring and infrared temperature measurement. At present, the online monitoring projects carried out by the miniature current transformer mainly include measuring the capacitance and dielectric loss factor tgδ of the main insulation, and measuring the insulation resistance and dielectric loss factor tgδ of the end screen insulation. Test experience has shown that it is effective in detecting insulation defects. For infrared temperature measurement, some units have already carried out, the existing test results show that it is effective in detecting the looseness of the internal joint of the current transformer, but it still needs to accumulate experience.