Bird Blake posted an update 11 months, 2 weeks ago
Sometimes adding more ground rods and pipes won’t do achieve almost anything to bring the ground resistance down in high resistivity areas. Especially sometimes, adding more ground rods will not likely a single thing to take the resistance down (the resistance stays the same).
A good knowledge of soil resistivity and related tests are vitally important. Some guidelines should be established for your soil testing. Similarly the testing and spacing to ascertain the soil resistivity with depth is essential especially if deep grounding/earthing elements will probably be used.
An increased than acceptable ground resistance would get a new safe operation of power system. Several various methods ended up utilized for yesteryear to decrease the grounding resistance with the grounding system. Methods include enlarging the grounding/earthing grid, connecting the main grounding grid with an external grounding grid, enhancing the burial depth from the grounding grid, utilizing natural grounding object including steel foundations of structures, adding long vertical grounding electrodes or pipes, and changing the soils round the grounding grid with low resistivity materials and chemicals.
These procedures are suitable for different geographical situations however that does not always mean they’ll work without having a correct soil resistivity testing or proper evaluation and without assortment of acceptable data to justify their application. Actually, within a specific soil environment, 2 or more methods can be viewed to diminish the grounding resistance effectively.
The method to incorporate deep vertical grounding electrodes on the grounding grid is incredibly great at substations with small area. This process can utilize the low-resistivity soil layer and eliminate the high resistivity soil close to the surface affected by freezing and occasional temperature. In order to limit the grounding resistance, the explosive grounding technique was proposed to lower the grounding resistance of grounding grids in high resistivity area. The evaluation of the explosive grounding technique as with any grounding strategy is also suffering from cost.
One efficient method to slow up the earthing resistance of substation is to apply deep ground wells electrodes. Several kinds of deep ground wells exist: For example it is possible to drill 150 mm ground well and go 50 meters to 85 meters deep or higher in the ground before you reach moist soil ground water or limestone… The ground well is filled with bentonite material and non-corrosive material to boost resistivity.
To get your house this type of grounding you will need also to depend on enhanced or even more advanced grounding put in order to calculate correctly the grounding resistance since programs like ETAP or SKM would not have the mandatory power to do these calculations for the reason that grounding resistance with the equivalent model is not easily calculated. The grounding resistance of an deep ground well could be calculated by numerical analysis program according soil model. The SES software package can be utilized.
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