Electrical Earthing System Design & Soil Resistivity Testing
What are the procedures for creating an HV Earthing System Design? Also, how might these differ from an LV Earth design?
Firstly, although the principles underpinning HV and LV earthing are similar, the approaches are very different.
The first huge difference is the recognition that HV electrical earthing design is probabilistic in nature. Whereas LV earthing is far less so.
What do I mean?
[Read more…] about Earthing System Design Procedure A Probabilistic ApproachAwareness of step and touch potential, caused by a rise of earth potential. Is essential for anyone working on high-voltage power transmission and distribution systems above 1 kV.
A rise of earth potential is caused by electrical faults that occur at electrical substations. Power plants, or high-voltage transmission lines. Therefore, short-circuit current flows through the plant structure. And equipment and into the earthing electrode. Since the Soil Resistivity is not zero. Therefore, any current injected into the earth at the earth electrode produces a ‘Rise of Earth Potential’. This earth potential rise (EPR) is concerning an infinitely distant reference point. The resulting rise of earth potential can cause hazardous voltage. And, many hundreds of metres away from the actual fault location. Thus, many factors determine the level of hazard. Including available fault current. And, soil type, soil moisture, temperature, underlying rock layers. Also, clearing time to interrupt the fault.
[Read more…] about Rise of Earth Potential (RoEP) Know the RisksAwareness of step potential and touch potential risks, caused by an earth potential rise. Is vital for anyone working on high-voltage power transmission. Also, distribution systems above 1 kV.
Earth potential rise (EPR) is caused by an imbalance of electrical charges between the earth and an electrical system, it can occur at:
Therefore short-circuit current flows through the plant structure and equipment and into the earthing electrode.
This imbalance can be caused by a variety of factors, including:
[Read more…] about Reducing the Risk of Step and Touch Potential
