Current transformer explosion prevention measures

- Oct 09, 2019-

(1) Check if the lead connectors in the primary terminals in the transformer are in good contact.

The primary terminal lead joint of the current transformer should ensure good contact, and the contact area should be sufficient to prevent the current transformer from overheating. The L2 terminal and the expander cover should be connected with equipotential bonding to prevent potential suspension. In addition, the anti-rotation measures should be taken for the secondary wire to prevent the internal lead from being twisted.

(2) 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 the temperature change or the test voltage should be comprehensively increased from 10kv to Um/root 3. When the tgδ increment exceeds ±0.3%, the operation should be exited. . When the results of chromatographic analysis are abnormal, it is necessary to follow the analysis and examine its growth trend. If the data grows faster, it should be paid attention to. Eliminate the accident in the bud.

(3) Guaranteed normalization of busbar differential protection

In order to avoid the impact of the accident at the bottom of the current transformer capacitor core, it should be noted that the installation direction of the terminals L1 and L2 and the polarity connection of the secondary winding should be correct to ensure the normal input of the differential protection of the busbar. run

(4) Checking the short-circuit current

According to the development of the power grid, pay attention to check the short-circuit current of the current transformer location, and exceed the dynamic thermal current value of the transformer nameplate.

(5) Accumulating online monitoring and infrared temperature measurement

At present, the on-line monitoring projects carried out by current transformers mainly include: measuring the capacitance of the main insulation and the dielectric loss factor tgδ measuring the insulation resistance and dielectric loss factor tgδ of the final screen insulation. Test experience has shown that it is effective in detecting insulation defects. For infrared temperature measurement, some units are already underway. The existing test results show that it is effective for detecting the looseness of the internal connector of the current transformer, but it still needs to accumulate experience.