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Electrical Earthing System Design & Soil Resistivity Testing

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Test large electrode systems using heavy current – for more accurate earth electrode resistance measurements

I recently attended a training session with Omicron in Germany. So, looking at their primary injection test set for earth electrode and line impedance systems testing. I looked at how to set up a current injection. Potentially up to 100 A. Also, down an Overhead line or Feeder cable. To achieve good separation between the electrode under test and the auxiliary electrode.

Previously, test methods have relied on dedicated cables for the measurement. Which, has limited the available area to deploy the auxiliary electrode. Owing to land usage constraints and roads. So, being able to use something in a built-up environment on electrically large High Voltage systems. Thus, avoiding road closures. etc. Therefore, comes as a breath of fresh air to a lot of engineers facing this problem.

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How to Size High Voltage Earthing HV Conductors Correctly

The correct sizing of high voltage earthing (grounding) conductors is crucial for the safe and efficient operation of any electrical system. The size of the grounding conductor should be determined based on the maximum fault current that the system is likely to experience. As well as the voltage level and the type of earthing system being used.

In general, the grounding conductor should be sized to carry the maximum fault current for a specified duration without overheating or causing damage to the conductor or surrounding equipment. This can be determined using industry-standard calculation methods and guidelines. Such as those provided by the National Electric Code (NEC) or the International Electrotechnical Commission (IEC).

What size conductors should I use?

There a simple table I can use for this HV high voltage earthing design project. These are great questions and often asked. This post answers these questions together with the choice of conductor materials and jointing method within a high voltage earthing design project.

Assessing conductor size is entirely dependent on the electrical configuration and the load that the conductor must take. For example, an above-ground bonding conductor serves to transfer current with minimal voltage drop, from A to B. A directly buried conductor has an additional purpose. That of leaking the fault current or voltage into the local geology (as part of an electrode).

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Soil Resistivity Testing Ground Soil Resistivity

Ground Soil Resistivity is Part 1 of a series of short posts on Soil Resistivity Testing and the common mistakes encountered. We offer practical advice on how to avoid the Soil Resistivity Testing 10 Common Mistakes.

Soil Resistivity Testing 10 Common Mistakes

What is Ground Soil Resistivity?

‘Soil‘ is the term used in Electrical Earthing Design to define the upper geology. Which is of particular interest to us when designing earthing or grounding systems.  The soil is the local geology consisting of layers that are primarily composed of minerals, mixed with at least some organic matter. However this differs from their parent materials in their texture, structure, consistency, colour, chemical, biological and other characteristics.

Geologists might refer to soil as the combination of ‘drift’ and/or bedrock.  The layman might refer to Soil more as ‘dirt’ or ‘ground’ (not to be confused with the American term).

The soil is the loose covering of fine rock particles that covers the surface of the earth. Therefore the soil is the end product of the influence of the climate, relief (slope), organisms, parent materials (original minerals), and time. (http://en.wikipedia.org/wiki/Soil)

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