First, the current transformer polarity connection should be correct

Current transformers are generally marked with a reduced polarity. If the polarity is not connected correctly, it will affect the metering. Even when multiple currents in the same line are connected in parallel, all of them will cause a short circuit accident.

Second, the secondary circuit of the current transformer should be provided with a protective grounding point

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 current transformer should be provided with a protective grounding point. Only one grounding point is allowed, and the current mutual inductance is generally close. The cabinet terminal of the unit is grounded.

Third, the secondary winding is not allowed to open during operation

Otherwise, it will lead to the following serious consequences: high voltage on the secondary side, endangering personal and instrument safety; overheating may burn the winding; increase measurement error.

Fourth, on the relay protection device

The secondary circuit of the current transformer used for electric energy metering should not be connected with relay protection devices and automatic devices to prevent mutual influence.