Electrical Earthing System Design

If you have a concern about a High Voltage Power System issue, or a connection to the grid from embedded generation scheme, then you’re in the right place!

Woody Guthrie once said - “Any fool can make something complicated … It takes a genius to make it simple!”

We aim to take ‘Risk’ off the table for your high value critical assets - and in the process present the complexity into an easy-to-understand plan or strategy.

Electrical Earthing Design Soil Resistivity Testing flow chart

With over 20 years experience, there isn’t a scenario or problem that our Earthing Consultants and highly qualified CDEGS accredited Research Engineers haven’t seen or solved, which means you can breath a little easier knowing your Earthing System Design is in safe hands.

Using the latest world renowned industry accepted CDEGS software - Studies include fault current distribution (or split), earth potential rise (EPR), and safety voltages (Touch and Step) are studied.  These are packaged into a visual format that not only achieves compliance but can be understood by all disciplines involved in the project, not just the electrical team.

Having robust useable information that crosses the disciplines can make a real difference in delivery of a technically secure project - YOUR project!


Safety Calculations and Hot Site Assessment

Whether routine equations or advanced computer simulation, our safety calculations will deliver earthing design compliance. Using specialist software such as CDEGS and bespoke MathCAD equations, we can calculate Touch and Step Voltages, the modern day fundamental safety-related quantums for a high-voltage electrical installation.  Assessment of the external environmental impact of an earthing system design by calculating  surface voltages (Hot Zone), and transfer potentials to other nearby earthing systems or equipment.


About Soil Resistivity Testing

The importance of a robust Soil Resistivity Testing model free from errors cannot be understated!  The Soil Structure is a foundational requirement for every electrical earthing systems design - get this wrong and the subsequent electrical earthing system design  may be flawed.

Computer people amongst us would call this - GIGO (Garbage In = Garbage Out)

That’s why GreyMatters has invested in high signal injection specialist resistivity instrumentation, e.g. 400 - 800 V polarising compared with 50 - 150 V from the more common units like the DET2/2.

Having a high signal injection voltage gives you reliable, robust results in even the highest resistivity geologies to take doubt out of the equation!

Note: Always ask your earthing system design consultant what signal voltage is being used for Soil Resistivity Testing. See a recent series of articles Soil Resistivity Testing 10 Common Mistakes

From Condition Assessment Surveys, finite element analysis (FEA) software analysis using CDEGS and field earth measurements for high voltage applications from 11 kV to 1,000 kV (1 MV).


HV Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) Studies

Not all finite element software packages are the same, most earthing system design software continue to use a version of circuit theory based calculations to work out earth fault return current levels, step/touch potentials and similar safety critical data, which can lead to errors if all the data is anything less than perfect.

What finite element electromagnetic field theory software does for the engineer is unchain the range and scope of scenarios that can be modelled – it expands the possibilities of what can be studied to how Electromagnetic Fields produced by power systems can ‘interfere’ with, or interact with nearby structures and equipment.

So, maybe you have a GIS (Gas Insulated Switchgear) substation, or overhead power line that comes into close proximity and you know something is happening above ground, but not sure quite what?

An AC interference Study looks at this EMI (ElectroMagnetic Interference) voltage or circulating current that result which might be causing an inadvertent hazard.  Armed with this knowledge, measures can be designed to deal with the risk.

EMI and EMC studies are not limited to under the ground - above ground concerns can be studied - so let your imagination go! ...

Have a quick ‘Live Chat’ with one of our online research engineers.


Electrical Earthing System Design scopeElectrical Earthing System Design

  • Design of technically secure solutions, using the very latest best practices and software tools
  • Fault current distribution modelling
  • Rise of Earth Potential Studies (RoEP, EPR or GPR)
  • Safety Calculations for touch and step potentials.
  • Interference Studies
  • Onsite Surveys and assessments
  • Onsite FoP measurements
  • Soil Resistivity Testing
  • Soil modelling and analysis
  • Post Construction Audits
  • Stray Current Studies
  • Earthing Policy formulation
  • CAD drawings of earthing layouts

Recently, Electrical Earthing Systems across the world have appeared to consolidate and rationalise into a limited number of “foundational” standards which local codes are derived.  These are typically based on IEC or IEEE versions…


Electrical Earthing Standards & Codes of Practice

Electrical Earthing System Design

  • BS EN 50522 Earthing of power installations exceeding 1 kV a.c. 2010.
  • BS 7340  Code of practice for protective earthing of electrical installation, 2011.
  • EA Technical Specification 41–24. Guidelines for the design, Installation, Testing and Maintenance of Main Earthing Systems in Substations. 1992.
  • BS EN 5012  Railway applications Electrical safety, earthing and the return circuit. 2011.
  • EA Engineering Recommendation S34. A Guide for Assessing the Rise of Earth Potential at Substation Sites. 1986.
  • EA Engineering Recommendation S36. Procedure to Identify and Record "HOT' Substations. 1994 and amendment 2007.
  • IEC 479-1, Effects of Current on Human Beings and Livestock, IEC, 1994.
  • ISIS Practice EPT/PPS/B014, Working Practices at Electricity Stations, British Telecommunications.

If High Voltage Power Systems and Lightning are causing you concern why not have a quick ‘Live Chat’ below as a start? ...

"Working with GreyMatters has totally changed my expectations of a professional engineering consultancy firm … for the better! Technically, they were on the money! More importantly however ... they kept me updated throughout the entire project, which was so refreshing, and therefore quickly put my mind at ease that things were being taken care of." (C. Turgis)
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