Well, 2017 was an exciting year for the team GreyMatters. So, at the end of 2016, we set goals on what we wanted to achieve in 2017. The biggest success story which is probably closest to my heart is smashing the previous year’s lives-protected by HV Earthing/Grounding Design.
Continuing the theme for lightning design. I was having a technical discussion during a seminar in Germany. The question popped up regarding Lightning design on an AD plant (AD = anaerobic digestion) with long cable buried runs between plant areas – “What about the buried cables?” –
What do we do about Lightning protection for buried cables in Lightning design?”
The question was not aimed at surge protection, but at physical protection of the cables from a direct lightning strike. And before you say ‘what!!?’ – Yes, buried cables are at risk from direct strike attachments! [Read more…] about Lightning design for buried cables – really?
A common question on Lightning Protection Design that crops up time and again, is – “What is the rolling sphere method of protection?”
If you’re looking for a convenient definition in BS EN 62305. I can save you the hassle because there isn’t one! The closest you will get to a conveniently packaged definition is in para E.188.8.131.52 ..
… the positioning of an air-termination system is adequate if no point of the volume to be protected is in contact with a sphere of radius, r, rolling on the ground, around and on top of the structure in all possible directions. Therefore, the sphere should touch only the ground and/or the air-termination system.
Hmmm, not exactly succinct or useful, right?[Read more…] about Why Rolling Sphere Method is best
Floating Roof Tank Fires are Common
There are some 15 to 20 known Floating Roof Tank (FRT) fires per year. Floating Roof Tanks are especially vulnerable to the direct and indirect effects of lightning. A direct or a nearby lightning strike can cause electrical current to flow across the tank shell and roof. When these lightning currents arc across the roof/shell interface, they can ignite any flammable vapours present with devastating effect. [Read more…] about Floating Roof Tank Earthing Strategies – Bypass conductors for lightning
A number of organisations across the UK recommend a standard earthing design when building smaller scale substations. The key driver behind these is one of cost. Nobody wants to pay more than they have to. For an HV connection using a templated approach to meet Earthing Standards compliance kind of makes sense – or does it?
So, the question is – does installing a standard earthing design meet your obligations under the Electricity at Work regulations?[Read more…] about Standard earthing design – are they valid anymore?