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EARTHING AND GROUDING OF SUBSTATION
Discover overview, principles and grouding products dedicated for substation
Protection of electrical Substations
Equipotential networks on electrical substations
Introduction to permanent grounding of substations
The performance of an equipotential network is linked to the quality of the connections of the constituent elements. Generally speaking, the various metal elements and grounds of a source station must be connected to the general grounding network. It is essential that the connections have high mechanical strength, electrical contact and corrosion resistance.
On the following pictures, some examples of maintenance and installation of a buried grounding network on an electrical transformer station:
Objectives of permanent grounding for substations
In principle, a safe grounding design for substations has the following two objectives:
- Provide means to carry electrical currents into the earth under normal and fault conditions without exceeding operating and equipment limits or impairing continuity of service
- Ensure that a person in the vicinity of the grounded facilities is not exposed to the danger of a critical electric shock
A practical approach to safety associated with grounding concerns and aims to control the interaction of two grounding systems, as follows:
- Intentional grounding, consisting of grounding electrodes buried at a certain depth below the surface of the ground
- Accidental grounding, temporarily established by a person exposed to a potential difference in the vicinity of a grounded installation
It should never be assumed that any earthed component can be safely touched. A low earth resistance on a transformer station is not, in itself, a guarantee of safety. There is, in fact, no simple relationship between :
- The resistance of the entire grounding system
- The maximum shock current to which a person may be exposed
Therefore, a substation with a relatively low ground resistance may be unsafe, while another substation with a very high resistance may be safe or can be made safe by protective measures and/or careful design.
Principle of Protection
The MALTEP range for electrical substations
Schematic diagram for the protection of substations
Earth clamp
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Straight compression lugs with long barrel
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Exothermic welding
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C crimp connectors
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Cable holders
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Earth clamps
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Conductors
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Earth braids
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Earth clamps
Discover our range dedicated to sub-stations
Earth clamps for substation
The earth clamp for substations is a set of copper alloy blocks holding the earthing circuit loop
MALTEP / RTE equivalents
| Equivalences between MALTEP commercial references and RTE / CNER references | |
| CPAR50-120L | STN-75/116 - A1 mark |
| CPAR150L | STN-146 - A2 mark |
| CPAR185L | STN-182 - A3 mark |
Copper alloy earth clamps and bolts for metalic structures up to 20mm thick. Icc (A) withstand from 30 to 40 kA/1 s and 63kA/0,5s
CPAR50-120L
Double earth clamps for subsations
Similar to the earth clamp, it includes an additional set of copper alloy block allowing an additionnal earthing circuit loop
MALTEP / RTE equivalences
| Equivalences between MALTEP commercial references and RTE / CNER references | |
| 2CPAR50-120L | STND-75/116 - C1 mark |
| 2CPAR150L | STND-146 - C2 mark |
| 2CPAR185L | STND-182 - C3 mark |
Copper alloy earth clamps and bolts for metalic structures up to 20mm thick. Icc (A) withstand from 30 to 40 kA/1 s and 63kA/0,5s
2CPAR50-120L