Why should the secondary winding of current transformer and voltage transformer be grounded in use

During the use of current transformer and voltage transformer, the secondary winding shall be grounded to prevent the high voltage from entering the low voltage through the transformer after the insulation of the transformer is broken down, which will hurt the instrument and users. The secondary one point grounding of the transformer will not affect the normal use of the equipment, but also ensure the safety of personnel and equipment.

In order to ensure safety, the secondary side of the current transformer must be grounded to play a protective role in case of high voltage danger at the secondary side of the current transformer, so as to ensure the safety of personnel and equipment.

Current transformer function

In the production process, the use status of each primary equipment in the system is monitored to ensure the safe use of the power system. The current transformer usually converts the large current of the primary circuit into the secondary small current in positive proportion, and finally outputs the small current at the secondary side to the secondary instrument, relay protection and automatic device for use. Therefore, current transformer is not only the AC current source of electrical control, regulation, measurement and protection elements, but also the hub for the connection between electrical secondary circuit and primary circuit.

Why can't the secondary side of current transformer be open circuit? Because the secondary circuit of the current transformer is open, the secondary current disappears, and the demagnetization also disappears, which will cause high magnetic density in the iron core. Because the number of turns of the secondary side winding is much greater than that of the primary side winding, once the secondary side is open circuit, there will be a high voltage, sometimes up to thousands of volts, which not only endangers the secondary side equipment, but also seriously endangers personal safety.