A new approach to measure and control grounding resistance

摘要

Grounding is the only security precaution to transfer leakage electrical energy on an electrical system to the ground via electrodes and panels placed under the ground. In order to do this transfer, the contact resistance between grounding elements and ground must be very small. Nevertheless, the contact resistance of ground changes with variation of climate. In high temperature, humidity of ground decreases causing the ground resistance to increase. However, to prevent these changes in the ground, a new grounding system is established to measure and control grounding resistance by using humidity sensors, grounding electrodes and underground watering system. The voltage applied to electrodes creates a current to flow through ground which leads to calculate ground resistance. If resistance value is appropriate for the reference value, the system continues measuring, otherwise underground watering system is activated to decrease grounding resistance. Experimental results show that proposed method for measurement and control of grounding resistance is precise and can be applied to large systems.