When the power current transformer is used, it will be high voltage due to the primary side of the high-voltage power current transformer. When the primary and secondary coils are damaged by the insulation and the high-voltage breakdown occurs, the high voltage will enter the low voltage if the secondary coil is a little. Grounding introduces high voltage into the earth to ensure the safety of people and equipment.
Because the power current transformer is different in measuring and protecting the thickness of the winding core, if the connection is wrong, the accuracy of the measurement in normal operation is reduced, and the energy measurement is not accurate. Since the secondary winding of the power current transformer cannot be opened, the windings that are not used by the power current transformer need to be shorted.
Power current transformer wiring principle
1. The polarity connection should be correct. Power current transformer are generally marked with reduced polarity. If the polarity is not connected correctly, it will affect the metering. Even when multiple power current transformer are connected in parallel on the same line, all short-circuit accidents will occur.
2. The secondary circuit should be provided with a protective grounding point and connected reliably. In order to prevent the high voltage from entering the low voltage side after the insulation breakdown between the primary and secondary windings, the personal and instrument safety is endangered. The secondary side of the power current transformer should be provided with a protective grounding point. Only one grounding point is allowed, and the power current transformer is generally close. The cabinet terminal of the unit is grounded.
3. The secondary winding is not allowed to open during operation. Failure to do so may result in the following serious consequences: high voltage on the secondary side, endangering personal and instrument safety; overheating may burn the windings.
4. The secondary circuit of the power current transformer used for electric energy measurement should not be connected with relay protection devices and automatic devices to prevent mutual influence.