Recent content by cflatters

Many thanks I am currently trying to obtain either IEC 60287 or the IEEE 575-2014 to progress

I am currently looking at a design using single layer spaced cables installed on cable ladder, spaced De apart based on IEC 60502, the standard refers to cables earthed at each end (solidly earthed). The induced voltage when using 300mm Cu/XLPE/AWA/PFC cables to BS6622/7835 equates to 15.3V...

Just a beware Working with SKM PTW and undertaking fault level and protection studies ? Working recently with SKM I noticed that the system takes no account whatsoever of separate earth / grounding conductors entered in parallel with the power cables, therefore protection studies and fault...

Hevacomp and Amtech are bsaed on BS7671 which is a subset of IEC 60364 for UK. We also use SKM Powertools for systems analysis

And thats why its often referred to as voltage impedance

With DPC on this one all the way DO NOT USE MVA - ALWAYS USE kA The energy dissipation / heat is a function of I2t

T do the job properly, you have to consider a whole number of issues - in fancy words FMEA (Failure Mode Effects Analysis) - but put more simply; Look at the reslience of your network ? Look at each load, presumably you have certain critical loads (eg fire pump, water drainage pumps...

Look for the book on 'Symmetrical Component Theory' by J Lewis Blackburn. Also type in 'Symmetrical Components' in Google, recall reading a good article from Basler (John Horak I think)

DNO = Distribution Network Operator EPR = Earth Potential Rise

For the transmission line type type and length you mention, the 'nominal pi' method should provide a suitably simplified and valid model to calculate line conditions once you have calculate the transmission line parameters. Take a look at the Areva website, the PRAG handbook can now be...

In the UK, DNO's do commonly use NER's to limit earth fault current on their distribution network to values which do not give rise to excessive fault current. The NER's also assist in the limitation of substation EPR. We also commonly encounter NER's on clients 11,000V systems limiting fault...

Personally I agree with Skogscurra Cost is the main point though I have used a number of 3.3kV PFC units in the past for MV MCC's, though there were no power electronics drives involved. When specifying PFC for LV MCC's and switchboards I always advocate using detuned banks. These are larger...

Sounds like a college exercise to me !

Personally I regularly use SKM PowerTools - The CAPTOR module enables protection devices to be modelled and held in a database. CAPTOR produces time / current curves which model actual relay settings vs calculated system fault levels and enable protection relay settings to be dragged on screen.

Yes sorry Scotty for picking up on the obvious error - I had meant to say lower fault level