GM QUARTERLY GreyMatters Newsletter March 2014

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1 GM QUARTERLY GreyMatters Newsletter March 2014 Introduction Welcome to the second edition of our newsletter. In this issue we tackle CPD training, share a recent RFI, do a mini case study on a recent data-centre project in central Europe and give you a brief run down of what we need from you when requesting a soil resistivity study. CPD Accredited Training Continuous skill development is fundamental to our professional careers. It is to this end that GreyMatters kicks 2014 off in researching CPD Membership. GreyMatters delivers speech at STOCexpo 18th March 2014 We will update you with our latest CPD Accredited training over the course of the year. If you haven t yet seen our Electrical Fault Theory Video you can do so by visiting our GM homepage. In This Issue CPD accredited training Q&A Money Back Guarantee! Case study How to get the most from your Consultant Meet Mr Darcy GreyMatters Electrical Fault Theory 1

2 Steel structure construction design Source: Google Image Search Questions Answered Q: What is the best method for earthing a structural steel column, exothermic weld or mechanical bolting? A: Both the exo-weld or mechanical bolting are acceptable methods, HOWEVER Exothermic In stable controllable conditions, WITH appropriate preparation to the steelwork - this method will be reasonably consistent. And therein lies the rub!... Field/site conditions are rarely stable, let alone controllable! You also have to consider the steelwork itself and how it's been produced. Unless the steel has been post-cleaned after manufacture it will have lubricants and oils impregnating the surface layer, that are used during its forging/rolling process, these contaminants remain in the surface of the steel and when exposed to the massively quick rise in temperature during the firing of the mould will outgas (burn-off), which can and does cause fusion problems. It's similar to a 'dry' solder joint, where the process doesn't actually take but on the face of it, it appears as though it has - in addition, when measured it will visually show as OK... but in reality, it is a point contact giving a false positive measurement and when 'stressed' will likely fail. This 'dry' joint effect is also an issue when the steelwork is cold and the thermal input is not sufficient to reach full fusion (i.e. the steel acts like a thermal sink - negatively). In this case, you have to pre-heat the steel to lessen the temperature differential. cont d 2 For the colder climates, if it were me, I would 'prefer' the mechanical fix... but this is purely a preference - both are compliant

3 The 'test' of a dry joint is to shock the joint... get a hammer and hit it!! (all high tech stuff). Measurement by instrument alone will tell you nothing really. Finally, exothermic method is not controllable - once you've lit the powder, the chain reaction takes place and you have to stand back until it finishes. It is unlike brazing where you can control the amount of heat applied and react to the unexpected. So, yes exothermic method to structural steel is viable BUT it's not straight forward and absolutely requires more preparation than a bolted option. Pro's for bolted are 1. Controllable process (drilling is controllable and the torqueing up is) Source: millerwelds.com 2. Unaffected by steel rolling contamination issues 3. Low skill 4. Safer in poor weather. 5. Bolted joints can be remade if there's a problem Pro s and Con s for Mechanical Bolting Con's for bolted 1. Introduces corrosion if not accounted for, e.g. anti-oxidant conductive paste or denso AND stainless bolt-sets are recommended. 2. Removes structural metal from column (attention to where the column is drilled) but minimal risk Source: millerwelds.com 3

4 Large Scale [40MW] Data-Centre Central Europe Data Centre Case Study Objectives GreyMatters was engaged in 2013 with the remit to understand the existing power earthing arrangements and how they may perform in the case of a fault from the two 150kV supply lines feeding a ~40MW data-centre site. The second part of the remit was to develop a safe, compliant design to the latest EN50522 and IEC standards covering the expansion works. Location Completed in 2010, the 40MW data-centre is located in central Europe and due to increased demand for remote hosting resources, the data-centre was subject to significant expansion in Project Features Soil resistivity (ρ): 3 layer structure, high-low-high Money-Back Guarantee We recognise that when considering any new working partner for the first time, it can seem a bit of a risk This is why GreyMatters is the only consultancy of its kind with the confidence to offer a Money-Back Guarantee! Some of our clients who have also enjoyed this peace of mind include BP, Deerns, AWE, National Grid, RAF, WPD, MoD, Ineos, Rolls Royce and Essar to name a few. Geology: Primary Voltage (V1): Secondary Voltage (V2): clay on mudstone 150kV fed by 2 remote sources (29km/5.5km) 30kV Number of line towers: 96 To see full details visit 4 Money Back Guarantee

5 It s all in the details Supplying GreyMatters with information in relation to your soil resitivity studies in a timely manner from the get go will help save YOU money. Tick Tock We just cannot cannot start start without it! How to get the most from your GM Consultant So what do we need? Source Data: voltage, current, complex power... it's particularly important to try and get the "phase-to-earth fault current at the source bus" and the "3phase-to-earth fault current at the source bus". Other Data: transformer ratings, configuration (wiring), whether there's an earthing transformer or neutral resistor, phase angles (power factor), soil resistivity, fence and other conductive parts of site that might transfer a dangerous potential. Now what? If you haven t yet supplied us with all the necessary information for your project, you can do so here 5

6 Meet Mr Darcy Mr Darcy is the latest member of the local GM Sponsored eventing team. He is proudly owned and ridden by India who are both doing very well, shown here in their first cross country training session. MR DARCY In the next Issue 1. Embedded generation challenge 2. Static build up - a new IEC standard decoded 3. Rail electrification 4. Update on past quarter events Contact Us Give us a call for more information about our products and services GreyMatters Innovation Centre Bristol & Bath Science Park Dirac Crescent Emersons Green Bristol BS16 7FR Main: hello@greymattersglobal.com Visit us on the web at 6