Earth Mat for Substation are connected to the following aspects:
✅ The neutral point is the system through its independent earth.
✅ Equipment framework and other non-current carrying parts of the electrical equipment in the sub-station.
✅ All extraneous metallic frameworks are not associated with equipment.
✅ Handle the operating pipe.
✅ Fence if it is within 2 m from the earth mat.
Earth mats or grounding mats bring the connection to the earth indoors. They usually connect through a conductor inserted within the ground port of an electrical outlet. They help in limiting the ground potential & protect against the faulty current. They are used in a place where the large fault current is to be experienced.
While designing an Earthing Mat, the following steps are considered:
✔ If the switchyards have soil that is low in resistance, the earth resistance of the Earthing system would also be low. If the soil resistivity is high, the mesh rods are placed with closer spacing (with more electrodes inserted in the ground).
✔ The voltage between the ground and the ground surface is not dangerous to a person during a fault condition. A person who may have to come in contact with the non-current-carrying conducting surface of the electrical system is safe during a fault condition.
✔ Interrupt a fault current that may flow into the Earthing mat if large enough to operate the protective relay. The resistance of the ground is low to allow the fault current to flow through it. Therefore, the resistance of the mat will not permit the flow of fatal current into the person’s body.
Ideally, the ground around the substations should have zero ohms resistance. There is no established ground resistance standard threshold available or recognized by agencies. However, the NFPA and IEEE have recommended a ground resistance value of 5.0 ohms or less. To achieve this, the substations must:
1. Have a neutral connection to the earth for generators, transformers, capacitors, and reactors.
2. Offer a Low-resistance path to the earth for the currents resulting from ground faults, lightning rods, surge arresters, gaps, and other devices.
3. Limit the potential differences that appear between the substation metallic objects or structures and the Ground Potential Rise (GPR). Due to the flow of ground current, they may pose a danger to equipment and personnel.
4. Improve the operation of the protective relay scheme to clear ground faults.
5. Increase the reliability and availability of the electrical system.
6. Allow the grounding of de-energized equipment during maintenance
For more information on Earth Mat, read our blog [ Ссылка ]
0:00 Introduction
0:39 Why do substations need Earth Mats?
1:38 Touch & Step Potential
3:00 Substation Earthing System
4:50 What causes a fault in a Substation?
5:34 How are Earth Mats Designed?
6:64 How do Earth Mats help in Substation Grounding?
Visit us at [ Ссылка ] | Follow us on LinkedIn at [ Ссылка ]
Axis is a leading manufacturer and supplier of Electrical Components to over 80+ Countries. To get a quote or to talk to our industry expert write to us at sales@axis-india.com.
#earthing #EarthMats #substation
