What are the requirements of Distribution equipment grounding resistance (二)

 What are the requirements of Distribution equipment grounding resistance (二)

1. when the building power distribution transformer installed inside the building, shall meet the following requirements:

I. for the distribution transformer work on the high pressure side is not grounded , Petersen coil grounded and high- resistance grounded system, when the transformer ground grounding resistance is not more than 4Ω, low-voltage system power ground with the grounding transformer protection common ground network ;

II. distribution transformer high side work in low resistance grounding system , grounding resistance protective grounding grid when the transformer conforming to this specification equation ( 12.4.1-1 ) requirements and the building uses the total equipotential bonding , Low system power ground to protect the common ground network and the grounding transformer.

2. lightning surge protection of distribution transformers which should be common ground network with transformer protection and grounding.

3. column distribution circuit breaker protection , load switch and capacitor banks , etc. , it should be connected to the equipment grounding conductor casing, and grounding resistance should be greater than 10Ω.

4. TT system, when the system ground and electrical equipment has been exposed conductive part of the total equipotential , the electrical equipment exposed conductive parts do not separate grounding grid ; if not performed total equipotential when exposed to an electrical device conductive parts should be set to protect grounding grid.

5. all the electrical grounding system of the building is appropriate to the same grounding grid . Resistance grounding module grounding grid , which should meet the minimum requirements.

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