The Method Research Of DecreasingQingYan 110kV Substation Grounding Resistance

Grounding resistance is important parameter of grounding grid. If the grounding resistance is higher, the part voltage of grounding system would raise unexpected, which would threat the stuff, destroy the device insulation, cause control device incorrectly work, enlarge the losses.QingYan 110kV substation is located in YunGui highland, the grounding resistance is higher than regulation because its small areas and complex geologic which would bring potential danger. So, it is necessary to decrease the grounding resistance to. eliminate danger and ensure the safety of stuff and power system.Using rod electrodes is a good decreasing resistance method if the bottom soil resistivity is lower than upper. This paper analysis and research the length, quantity, space and utilizing coefficient of rod electrodes.The centralizing grounding devices are used and causes good effect in the small location, high soil resistivity substation.This paper analyzed the effect to grounding resistance of the device's shape, device's section diameter, height and depth which was the base of engineering application through lots of simulate calculations. It also analyzed the effect of grounding hole to the resistance, the influence of backfill soil resistivity, the hole's section diameter and the hole's depth to the resistance.By lab simulate experiments, it verified the model, the calculation model and the program. It also proved the effect of grounding hole and affused water to the device's grounding resistance.This paper analyzed the effect of shielding between hollow grounding devices and between hollow grounding device and ground grid. It also put forward the way to apply the hollow grounding device.This paper validate the accurate of calculating centralizing grounding device through the QingYan grounding project, offer a new method of decreasing substation resistance.