How to avoid common problems of current transformer

How to avoid common problems of current transformer
Read all the internal rules and regulations and manuals related to the commissioning of current transformers.
Check the secondary wiring board and there should be no damage such as bumps, scratches, etc.
Before assembly, the surface of the product casting body should be free from bumps, scratches, sanding and other defects to ensure that the surface is clean.
Check the appearance of the transformer and there should be no damage, especially no cracking.
Check the secondary wiring to ensure that there is no winding connection failure. Make sure that each contact point is in good contact. The ground terminal must be on the base.
Measure the DC resistance of each winding, and the difference between the measured value and the factory value shall not exceed 12% (converted to the same temperature).
Measure the no-load current and no-load loss, and the difference between the measured value and the factory value shall not exceed 30%.
Measure the insulation resistance between the windings and to the ground. Use a 2kV megohmmeter to measure at room temperature. The measured value should have no actual difference with the factory value.
The secondary windings and residual voltage windings of the transformer are not allowed to be short-circuited.

Check the grounding condition
Check whether the connection of the grounding bolt in the cabinet is firm.
When the transformer is running, its box must always be grounded. Apply the grounding plate on the box.
Each secondary winding cannot be grounded more than twice (that is, it cannot be grounded more than twice at the same point)

Check whether all ground connections are firm
All connections, including bolt connections, must be firm and have low contact resistance.
And they must all be corrosion resistant.

Ensure that the secondary winding of the voltage transformer is not short-circuited
The load connected to the secondary winding cannot exceed the rated value (refer to the nameplate data).
The unused secondary winding must be grounded at the terminal end.