How to ensure the long-term stable operation of the zero-sequence current transformer?

1. Correct installation
Installation location: The zero-sequence current transformer should be installed on the bottom plate of the switch cabinet and fixed with a reliable bracket. Ensure that the installation location meets the design requirements and avoid installation in places that may be subject to mechanical damage or environmental influences.
Grounding wire processing: According to the location of the cable grounding point, correctly handle the grounding wire. When the cable grounding point is below the transformer, the grounding wire should be directly grounded; when the grounding point is above the transformer, the grounding wire should pass through the transformer for grounding. The grounding wire must be made of copper stranded wire or tinned copper braided wire with a cross-section of not less than 25mm².
Magnetic circuit closure: Ensure that the magnetic circuit of the zero-sequence current transformer is closed. During the installation process, avoid the magnetic circuit not being closed due to the cable terminal head being too large.
Secondary connection recovery: If the secondary connection of the zero-sequence current transformer is disassembled during construction, it must be restored in time after the work is completed to avoid the secondary coil being open.
2. Daily maintenance
Appearance inspection: Regularly check the appearance of the transformer to ensure that there is no damage, no looseness, and the grounding wire is firmly connected.
Cleaning and maintenance: Keep the surface of the transformer clean to avoid dust and dirt accumulation, which will affect heat dissipation and performance.
Check the wiring: Check the wiring of the transformer regularly to ensure that the wiring is firm, without looseness or damage.
3. Regular calibration
Calibration cycle: To ensure measurement accuracy, the zero-sequence current transformer should be calibrated regularly, usually at least once a year.
Use professional equipment: Professional testing equipment should be used for calibration to ensure the accuracy of the measurement results.
4. Monitoring and adjustment
Monitor the output signal: Regularly monitor the output signal of the zero-sequence current transformer to ensure that it can reflect the current changes in the system in a timely manner.
Timely adjustment: When the output signal is found to be abnormal, the device connection status should be checked immediately and necessary adjustments should be made.
5. Prevent external interference
Avoid electromagnetic interference: During installation, try to avoid strong electromagnetic interference sources around the transformer and ensure that the system is well grounded.
Good grounding: Ensure that the grounding system of the transformer is good to avoid measurement errors caused by poor grounding.
6. Acceptance and commissioning
Construction acceptance: After the construction is completed, the protection professionals and operation professionals should be arranged to accept the zero-sequence current transformer.
Commissioning the protection system: The zero-sequence protection system must be adjusted before power is turned on to ensure that the protection works normally.