Project background:
In a 200 MW mountain project, Huawei SUN 2000-175KTL-H0 inverter and SmartACU2000B (with PID) communication box are used. During communication commissioning, the PID communication of a communication box cannot be connected.
Fault locating:
When you touch the shell of the communication box during the communication commissioning, you may feel electric shocks. Therefore, the power supply of the communication box may be faulty.
1. Cables inside the communications cabinet are incorrectly connected, causing current leakage.
2. The single-phase power and three-phase power cables from the box-type transformer in the communications cabinet are faulty.
Handling Procedure:
1. Before the communication commissioning, the multimeter has measured the box-type transformer wiring switches of the single-phase power cable and three-phase power cable in the communications cabinet. Therefore, the cable connection of the box-type transformer is normal.
2. Power off the communications cabinet and check the cables to the communications cabinet. No exception is found. All internal cables are correctly connected.
3. Power the communications cabinet again. When you touch the shell of the communications cabinet, the electric shock still occurs. Use a multimeter to measure the voltage of the three-phase power cable on the communications cabinet side, the voltages of phase A and phase B of the three-phase power supply A, B, and C for the PID module are 0. The voltages of phase C are normal.
Check the two power cables of the communications cabinet again. It is found that the screws on the three-phase power cables are not tightened, causing the PID power supply to be abnormal. Slight current leakage in the communications box
