Operation process and range inspection of open zero sequence current transformer

- May 03, 2019-

After the time on the secondary terminal of the open zero sequence current transformer, the loose current is greatly heated or oxidized and overheated to open the circuit. The circuit indicator indicates abnormality. Generally, it is reduced to zero when performing operation, and is mainly used for measuring meter when used. The current loop is open, which causes the three-phase ammeter to indicate inconsistency, the power meter indication to decrease, and the meter speed to be slow or not. If there is no time when the meter indicates, it may be in a semi-open state (poor contact).

In the normal operation process, the open zero sequence current transformer has no load at the time of use and no work at the second time.

When the current loop of the measurement is not open, the secondary open circuit fault of CT is not easy to find. For the CT secondary open circuit fault check processing, the primary load current should be reduced as much as possible to reduce the voltage of the secondary circuit. Pay attention to safety during operation. Stand on the insulation mat, wear insulated gloves, and use well-insulated tools.

If the open zero sequence current transformer is found to have a spark when short-circuited, the short-circuit should be valid. The fault point should be in the loop below the short-circuit point and can be further searched. If there is no spark when shorted, the short circuit may be invalid. The fault point may be in the loop before the short contact point. The short contact point can be changed forward point by point, and the range check can be narrowed.