Problems that must be paid attention to in the maintenance and repair of current transformers

1. For high-voltage current transformers in operation, the secondary coil should be grounded at one point. When the secondary coil is subjected to high-voltage thermal breakdown due to thermal breakdown of the insulating layer, a high working voltage can be introduced to the ground to maintain the secondary coil at the ground potential difference, thereby ensuring the safety of the body and equipment. Also, the current transformers are only allowed to be grounded a little. If 2 points are grounded, it will cause a separation to enhance electrical equipment data errors or jeopardize the proper operation of the protector.

2. The secondary load of the current transformer in operation is the current solenoid coil of the instrument panel. Its characteristic impedance is not large, and most of them are short-circuited. In that way, the relative density of the magnetic flux in the magnetic core can be maintained at a low level because the orientation of the magnetic flux caused by the secondary current and the magnetic flux caused by the primary current are reversed. At this time, the relative density of the magnetic flux in the magnetic core can be maintained at a low level. "The working voltage is also very low again. When the current transformer is activated again, the current on the primary side will not change, the current is zero again, and the actual effect of demagnetization subsides. The primary and intermediate currents will be used to excite the current mutual inductance. Because the number of turns of the coil is several times that of the first coil, the high voltage on both sides of the electromagnetic coil will be magnetically induced to a working voltage many times larger than that of the original coil. The safety of all electrical equipment and employees in the secondary circuit will be affected and risked. In addition, because the magnetic flux is suddenly saturated in the magnetic core, the magnetic core will be saturated. The loss will increase, resulting in heat generation. Serious high temperature will even cause the transformer to burn out. On the other hand, even if the transformer is not damaged, the residual magnetism caused by the saturation of the transformer core will increase the deviation of the transformer. Therefore, most of the work is not allowed to turn on the secondary side of the current transformer, and it is necessary to maintain the browsing condition reliably. .If it is found that the circuit is re-directed during operation, the switching power supply should be disconnected first. When the load does not allow the power failure, the load current on the primary side should be reduced, and then use an insulating tool to solve it.

3. During the operation of the secondary circuit of the current transformer in operation, in addition to filling in accordance with the provisions of the "Code of Safe Work", the following matters should also be paid attention to:

(1) For any reason, most of the current transformers are not allowed to open twice.

(2) Because it is necessary in work, the secondary circuit of the current transformer is short-circuited. The short circuit should be selected as a short circuit, and it is strictly forbidden to use a fuse or usually twist the wire.

(3) It is forbidden to carry out all work on the route between the current transformer and the short-circuit point.

(4) When cleaning the secondary line, dry cleaning tools should be used. Workers must be careful and minimize the use of metal equipment.