Siemens APT transformer - the use of voltage transformer and precautions

Create Date: 2024-8-30 12:03:23|Source: APT/Siemens Shanghai Ergong

The voltage transformer output is usually 100V

1. The working impedance in the secondary circuit of the voltage transformer should not be too small to avoid overload operation.

2 Before connecting the circuit, the polarity of the voltage transformer should be verified.

3. After the circuit is connected, the secondary coil should be reliably grounded to prevent the high voltage from endangering the safety of personnel and equipment when the insulation on the primary and secondary sides is broken down.

4. The voltage transformer in operation shall not be short-circuited under any circumstances, and the fuse shall be installed on the primary and secondary sides, and the isolation switch shall be installed on the primary side.

5. During the power supply overhaul, the knife switch on the primary side and the fuses on the primary and secondary sides should be disconnected.

Siemens APT transformer - the use of voltage transformer and precautions

Precautions for the use of voltage transformers:

1. Before the voltage transformer is put into operation, it should be tested and inspected in accordance with the rules and regulations. For example, polarity, connection 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 circuit under test, and the secondary winding should be connected in parallel with the voltage coil of the measured appearance, relay protection device or automatic device, and the correctness of the polarity should be paid attention to.

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, the error of the transformer will increase, and it is difficult to achieve the correctness of measurement.

4. Short circuit is not allowed on the secondary side of the voltage transformer. Because the impedance in the voltage transformer is very small, if the secondary circuit is short-circuited, it will present a large current, which will damage the secondary equipment and even endanger personal safety. The voltage transformer can be equipped with a fuse on the secondary side to protect itself from damage caused by a short circuit on the secondary side. Where possible, a fuse 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 the failure of the transformer's high-voltage winding or lead.

5. In order to ensure the safety of people when contacting the measurement surface and relay, the secondary winding of the voltage transformer must be grounded. Because after grounding, when the insulation between the primary and secondary windings is damaged, it can prevent the appearance and relay from presenting high voltage and endangering personal safety.

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