Application guide for equipotential earth mat installation on substation structure mounted switches version.
Earth mat testing procedure.
The substation earthing system comprises of a grid earth mat formed by a horizontal buried conductors.
This method is derived from the 4 point method which is used for soil resistivity measurements.
Bureau of standards now nist developed.
Several tests are conducted to check the safety of products.
The 3 point method called the fall of potential method comprises the earth electrode to be measured and two other electrically independent test electrodes usually labelled p potential and c current these test electrodes can be of lesser quality higher earth resistance but must.
Earth electrode conductive part which may be embedded in the soil or in a specific conductive medium e g.
One among that is earth test.
In order to obtain a low enough value of earth resistance earth systems may consist of an earth mat covering a large area or many interconnected rods.
Various governments and agencies have developed stringent requirements for electrical products that are sold world wide.
Such type of system helps in limiting the ground potential.
The measuring procedure described here uses the wenner method and uses the formula.
2 oct 2005 5 of 11 testing procedure before installation of gratings lv rubber gloves must be worn at all times when test leads are connected to the substation earths.
Suitable test techniques must be used for large systems to ensure valid readings are obtained.
Earth electrode resistance the resistance of an earth electrode to earth.
It reduced the overall grounding resistance.
The grounding system in substation is very important.
In a tt system where a connection to earth is not provided by the.
Mat ansi astm d178 or equal while operating the test set.
Earthing mat is made by joining the number of rods through copper conductors.
Testing large earth systems.
While designing an earth mat the following step is taken.
Measure the resistance of the mgn.
Electrical safety testing is essential to ensure safe operating standards for any product that uses electricity.
Read about design of substation earthing system here.
Thirdly measure the individual resistances of the ground system using the selective test of the earth ground tester see fig.
The value is the resistance of that particular leg of the mgb.
An earth electrode and earth electrode resistance are defined in bs 7671 as.
This is unlike a small single electrode for example a lightning.
