Problems with low-voltage distribution systems
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This post was last edited by zhoudingshengs on 2024-1-23 09:34. Discussion: 1. The low-voltage distribution systems in electrical engineering generally include TN-C, TN-S, TN-CS, TT, IT, etc. (1) What method should be used for the AC power supply to instruments? (2) Which of the above methods has a separate PE wire? (3) Which of the above methods combines the neutral line and the ground wire? (4) Which of the above methods does not have a PE wire?
1. The grounding methods for low-voltage distribution systems in electrical engineering mainly include TN-C, TN-S, TN-C-S, TT, IT, etc. (1) Instrumentation AC power typically requires high power quality and safety, therefore, the TN-S or TT system is generally recommended. These two methods provide good electrical isolation and ground protection, which helps ensure the stable operation of instruments and reduces electrical interference. (2) The systems that have a separate PE wire are TN-S, TN-C-S, and TT systems. In a TN-S system, the N wire (neutral wire) and the PE wire (protective earth wire) remain separate from start to finish. The TN-C-S system is in the TN-C form up to a certain point, after which it splits into separate N and PE wires. The TT system also has a separate PE wire, which is separate from the ground wire of the power grid. (3) The system in which the neutral line and ground wire are combined is the TN-C system. In a TN-C system, the neutral wire (N) and the protective earth wire (PE) are combined together, usually referred to as the PEN wire. (4) The IT system is the approach without a PE wire. In IT systems, there is a neutral point that is not directly grounded or has a high-impedance ground connection; as a result, there is no separate PE wire, and safety is ensured through local grounding and fault limitation devices. .
This post was last edited by zhouds on 2023-12-8 09:22 (1) The TN-S system should be used for AC power supply in instruments. (2) N-S and TN-CS have separate PE wires. . (3) TN-C combines the neutral wire and the ground wire. (4) TT and IT do not have a PE wire.