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List of contents of this article:

• 1,DigiPlus fair value Grounding principle of electric vehicle it system
• 2, What is TH system, TT system, IT system? Why is it recommended to use three-phase five-wire system?
• 3, What does IT system mean?

Electric vehicle it system grounding principle

IT system is to protect the grounding system. The so-called grounding is to closely connect a part of the equipment to the earth through the grounding device.

The ground voltage is the potential difference between the charged body and the earth with zero potential. Obviously, the ground voltage is equal to the product of the grounding current and the grounding resistance: Ud=Rd×Id.

The neutral wire of the transformer is grounded and divided into two, one is for the working zero wire and the insulation, and the other is for the protection of the zero wire and the shell. This is the so-called TN-S system (i.e. three-phase fire wire, a zero wire, and a ground wire).

What is TH system, TT system, IT system? Why is it recommended to use three-phase five-wire system?

TT TN IT power supply system is named according to the different neutral point grounding N, public protection line PE, and protection neutral line PEN junction.The TT system refers to the three-phase four-wire, the neutral point is directly grounded, and the equipment is connected to the PE line. That is, the equipment shell is directly grounded.

TT system is a system in which the neutral point of the power supply is directly grounded and the shell of the electrical equipment is also directly grounded. Usually, the grounding of the neutral point of the power supply is called working grounding, and the grounding of the equipment shell is called protective grounding. In the TT system, these two groundings must be independent of each other.

TT system is a system in which the neutral point of the power supply is directly grounded, and the exposed conductive part of electrical equipment is also directly grounded. Usually, the grounding of the neutral point of the power supply is called working grounding, and the grounding of the exposed conductive part of the equipment is called protective grounding. In the TT system, these two groundings must be independent of each other.

What does IT system mean?

IT system is a kind of low-voltage power distribution system, and "protective zero connection system" is only a one-sided statement. Definition of IT system: a system in which the neutral point of the power supply is not grounded, and the exposed conductive part of the electrical equipment is directly grounded. The IT system can have a neutral line, but IEC does not recommend setting a neutral line.

IT system is the right way to protect the zeroing system. It is a system in which the charged part of the power supply system is not grounded, or the exposed conductive part of the electrical equipment is grounded through impedance grounding. Nowadays, most of the grounding and zeroing systems adopt the standards stipulated by the International Electrotechnical Commission (IEC).

IT system is an international standard IEC60364 that distinguishes three different types of grounding systems, using two letter codes to represent TN, TT and IT. The first letter indicates the relationship between the power supply end and the ground: T indicates that the power supply end is directly grounded;I means that all the charged parts of the power supply are not grounded or grounded by impedance.