Check the strength of the grounding device and the grounding system. Grounding must be good and the measured grounding resistance value must meet the design requirements.
It is necessary to check the system wiring in detail. Except for the special protection (PE) and the neutral line (N line), which are directly connected to each other at the neutral point of the transformer, no connection is allowed in the future and they must be well insulated. So check carefully to rule out incorrect wiring.
The commonly used TN-S system (that is, the original three-phase five-wire system) is a power system that strictly separates the working neutral line N and the ground wire PE on the user side. The neutral line is generally not allowed again. The distance of the power transmission path determines the length of the neutral line. When the cross section of theneutral line remains unchanged, the length of the neutral line also determines the resistance value of the neutral line. There is resistance on the neutral line. Once current passes through the neutral line, zero ground voltage is generated.
Detailed information:
1. Grounding does not meet requirements;
2. -The phase power load is unbalanced;
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3. High frequency harmonics
4. Other reasons (the cable is too thin, the distance is too far, etc.);
Baidu Encyclopedia - Zero voltage to ground
Alternating current The UPS output does not have a neutral wire and a live wire. You just need to connect one. If it is grounded, it iscalled the neutral line. If measured at that time, the voltage to ground. should be zero volts. There may be some voltage when measured when ungrounded. This is induced electricity. Size is related to many factors, but it is not used as a machine indicator and has no practical significance.