03,20,2026 18views
Core precautions for installation and wiring process
1. Safety measures are the primary prerequisite
Strictly implement safety technical measures such as power outages, electricity inspections, hanging grounding wires, and hanging signs.
At the PT terminal box, the relevant secondary circuits should be disconnected and insulated to prevent PT short circuits caused by accidental contact during operation.
2. Voltage circuit wiring
Principle of preventing open circuit: It is strictly prohibited to open the voltage circuit. Suitable tools must be used when wiring to ensure that each screw is securely fastened. After taking over, another person must tighten it again.
Winding correspondence: Strictly connect the correct PT winding according to the drawing, ensuring that phases A, B, C, and N (L1, L2, L3, N) are correct and not connected incorrectly.
One point grounding: The voltage secondary circuit must be reliably grounded at the PT terminal box on site, and there should be no repeated grounding inside the cabinet to prevent the influence of circulating current caused by ground potential difference on protection action.
Wire diameter and color code: Use multi stranded copper core wires with a specified cross-sectional area (usually not less than 2.5mm ²) and follow the standard color codes of yellow (A), green (B), red (C), and black (N).
3. Wiring of power and signal circuits
DC power supply:
Verify that the power supply voltage level (such as DC 110V/220V) is consistent with the device requirements.
Pay attention to positive and negative polarity, and it is strictly prohibited to connect them in reverse. Recommend using blue (negative) and brown/red (positive) lines.
The capacity of the power switch in the screen should match the device.
Input quantity (signal) circuit:
Confirm that the voltage of the input power supply (DC+KM or - KM) is correct.
When connecting signals, pay attention to the correspondence between the common end and each branch signal.
4. Communication and shielded wire wiring
Communication line: If connected to Ethernet or RS485 bus, the network cable crystal head or 485 interface should be made according to the specifications, and attention should be paid to the setting of terminal resistance.
Shielding layer grounding: The shielding layer of all analog and communication cables should be reliably grounded at one end on the cabinet side, and the grounding wire should be as short and thick as possible.
5. Installation of the device body
Push the device smoothly into the cabinet guide rail and tighten it with screws.
Ensure that there is sufficient space in front and behind the device for heat dissipation, wiring, and debugging operations.
3、 Commissioning and acceptance after installation
1. Insulation inspection before power on
Disconnect the power plug and other weak electrical interfaces of the device.
Use a 500V megohmmeter to measure the insulation resistance of the voltage circuit to ground and between each circuit, which should be greater than 10M Ω.
2. Preliminary power on inspection
Turn on the DC power supply and observe whether the device indicator light and LCD display screen are normal without any abnormal alarms.
Check if the software version and clock are accurate.
3. Voltage circuit nuclear phase verification
Nuclear phase (phase determination): After restoring the wiring at the PT terminal box, measure the three-phase voltage and phase to phase voltage with a multimeter at the device terminal block to confirm that the amplitude and phase sequence are correct.
Verification: Use a relay protection tester to apply standard voltage and verify the measurement accuracy and protection settings of the device for correctness.
4. Signal transmission test
Simulate various abnormal signals (such as PT disconnection, overvoltage, low voltage), and verify whether the signal indications and communication messages are correct in the local and background monitoring systems of the device.
