Q: What aspects should be paid attention to when testing the wiring of line parameters?
Answer:
1. The protective grounding column on the instrument panel and the N terminal of the test power output must be reliably grounded, and the tested circuit must be reliably grounded through a grounding knife switch during the wiring or disconnection process.
2. The connection between terminal N and the ground grid must be reliably connected with a dedicated grounding wire of no less than 6 square meters to reduce the impact of contact resistance and the grounding wire's own resistance on zero sequence impedance; If a temporary short-circuit wire is used for grounding at the end of the line, a dedicated grounding wire of no less than 6 square meters should be used to reduce the impact of line resistance on the zero sequence result.
3. The work site and protective grounding should use the grounding grid of the substation, and the grounding device of the line tower should not be used. It cannot be directly connected to the grounding lead of the composite optical cable overhead ground wire (OPGW).
4. After the instrument is reliably connected to the ground, the test line should be connected to the power output port of the instrument first, and then to the voltage measurement port; After the experiment is completed, the voltage wire should be removed first, then the current wire, and finally the grounding wire.
