Precautions For Voltage Transformers

1. Before putting the voltage transformer into operation, it should be tested and inspected according to the specified items in the regulations. For example, measuring polarity, connecting groups, shaking insulation, nuclear phase sequence, etc.
2. The wiring of the voltage transformer should ensure its correctness. The primary winding should be connected in parallel with the tested circuit, and the secondary winding should be connected in parallel with the voltage coil of the connected measuring instrument, relay protection device, or automatic device. At the same time, attention should be paid to the correctness of polarity.
3. The capacity of the load connected to the secondary side of the voltage transformer should be appropriate, and the load connected to the secondary side of the voltage transformer should not exceed its rated capacity. Otherwise, it will increase the error of the transformer and make it difficult to achieve measurement accuracy.
4. Short circuits are not allowed on the secondary side of the voltage transformer. Due to the small impedance inside the voltage transformer, if the secondary circuit is short circuited, a large amount of current will occur, which will damage the secondary equipment and even endanger personal safety. Voltage transformers can be equipped with fuses on the secondary side to protect themselves from damage caused by secondary side short circuits. If possible, fuses should also be installed on the primary side to protect the high-voltage power grid from endangering the safety of the primary system due to faults in the high-voltage windings or leads of the transformer.
In order to ensure the safety of people in contact with measuring instruments and relays, the secondary winding of the voltage transformer must have one point grounded. Because after grounding, when the insulation between the primary and secondary windings is damaged, it can prevent high voltage in the instruments and relays from endangering personal safety.
6. Short circuits are absolutely not allowed on the secondary side of voltage transformers.