Precautions for handling short-circuit faults of high-frequency transformers

author: MagTop
​​​​​​​12v 10 amp transformer,electronic transformer 12v, High frequency transformer
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1.When replacing the insulation, the insulation performance should be guaranteed
Test the replacement insulation performance during processing, and use it only if it meets the requirements. Special attention should be paid to the insulation of the lead bracket wood blocks. Before installation, the wooden block should be placed in the thermal high frequency transformer,current transformer oil around 80°C for a period of time to ensure the insulation of the wooden block.

2.The insulation test of high-frequency transformer should be carried out when the high-frequency transformer is sprayed with oil for 24 hours
Since some wet insulation parts will be immersed in hot oil for a long time, moisture will spread to the insulation surface, so insulation defects cannot be detected after oil injection. For example, a 110 kVA + low-voltage side of 31.5 MWa is treated with a 10kV copper rod support block. After injecting high-frequency transformer oil, everything is normal in the test, and the insulation resistance of the 10kV low-voltage side to the core, wire clamp and ground is reduced to about 1Ω. After inspection of the hanging hood, it was found that the insulation of the 10kV copper bar supporting wooden block was very low. Therefore, the insulation test should be carried out after 24 hours of oil injection in the high-frequency transformer, which is more reliable.

3.Pay attention to the sharp corners of the core when reinstalling the core
When installing a yoke on the iron core, pay attention to the sharp corners of the core chip, and the insulation between the oil channels should be measured in time, especially the sharp corners of the chip at the oil passage to prevent the overlap of chips from causing the core to be grounded at multiple points. For example, when replacing a 120MVA220kV high-frequency transformer with a low-voltage side yoke, the insulation between the oil channels was not measured in time because the sharp corners of the chip were not paid attention to, and the insulation between the oil channels was measured to be 0 after installation. After zui, because the sharp corner of the core chip is short-circuited to the oil channel, it takes a long time to find.

4. Replace the winding material with strong resistance to short circuit