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  1. IrishPower

    ETAP vs DIgSILENT PowerFactory.

    I have used both ETAP and PowerFactory in a previous role (using CAPE now in my present role). ETAP seems more tailored/focussed on industrial power systems while PowerFactory seems to be used more for transmission power system modelling. As a result, the component models / libraries of each...
  2. IrishPower

    PSCC & PFC Measurement Accuracy Using MFT

    I have not used it, but perhaps something like the Megger NIM1000 is along the lines of what you are looking for?
  3. IrishPower

    Touch voltage 2-pole short circuit

    Hans-Henrik, The notes under Table 1 of EN50522 mention “if there is no automatic disconnection of earth faults, the need to consider double earth faults depends on operational experience”. This might be relevant if your 10kV system is operated with isolated neutral or resonant earthing. The...
  4. IrishPower

    Rotor angle in a 4-machine system.

    Are you plotting relative rotor angles? If so, your swing generator will be the reference for the relative angles of the other generators and appear to be at zero degrees during the simulation. If you have a second identical generator at the same bus as the swing generator that could explain why...
  5. IrishPower

    ETAP not adding fault currents correctly

    Kaspor, I suggest that you are too quick to suggest that ETAP is “not adding fault currents correctly”. The detailed printout you provided clearly shows that the real and imaginary components add up at the bus and Kirchoff’s current law is satisfied. Yes, the different currents have different...
  6. IrishPower

    Design ground substation on a rocky terrain

    slugz, If you expect a high ground grid resistance, bear in mind that this may reduce / restrict the ground fault current to less than the 14 kA value you mentioned. This won't solve all of your problems, but if your utility allows you to do this it may knock a few percent off your calculated...
  7. IrishPower

    Existing solutions to minimize the negative impact of wind power plants on the grid

    The Transmission System Operator in Ireland, EirGrid, has carried out a number of studies looking at the challenges faced by power systems with high levels of wind/non-synchronous generation. The reports include a number of possible solutions which may be of interest. The reports are available...
  8. IrishPower

    Data sources or technical references for HV transformer saturation curves

    Thanks prc, I found what looks some useful data on the websites of those manufacturers. Once we get confirmation regarding what grade of CRGO steel will likely be used in the transformer we should be OK. Thanks again, IP
  9. IrishPower

    Data sources or technical references for HV transformer saturation curves

    Hello, I am looking for any suggestions members may have for good data sources or technical references for typical saturation characteristics of HV transformers. We are looking for this information in order to carry out a preliminary transformer inrush / transient overvoltage calculation. In...
  10. IrishPower

    Prospective permissible touch voltage in acc. to EN50522

    Hi PeZeKa, The EN50522 standard doesn't make things easy, but it is possible to recreate the curves in Figure 4 and Figure B.2 using the equations shown in Annex A and Annex B (with more accuracy at some points than others...), and to use the same process to come up with alternative curves if...
  11. IrishPower

    Touch Potentials Beyond the Substation Grid System

    HI RSChinn, Short answer: Yes, I think you could in theory (and possibly in practice!) have touch potential issues at the metal stake or cyclone fence. In my own experience I have seen cases, both modelled and measured, where excessive touch potentials were present at third-party fences and...
  12. IrishPower

    IEC Lighning Design

    timm33333, If you are reasonably certain that you need a LPS anyway, then ScottyUK’s link is probably a good place to start, as this should indicate what Lightning Protection Level you require according to IEC 62305. As there are several different levels of lightning protection allowed for in...
  13. IrishPower

    earth system

    ... or EN50522 For complex earthing systems you can use more advanced earthing software such as CDEGS, but there's not much point in doing that until you learn the basics, starting with reading the relevant standards and using the simplified equations from these standards. Start by reading the...
  14. IrishPower

    Calculation of Touch and Step Voltage Limits using EN50522

    radug, Thanks for sharing the values you've been able to replicate from EN50522. It does seem strange that two of the values are different. I occasionally need to use touch voltage limits calculated using faster earth fault clearance times (in cases where there is duplicate fast-acting/reliable...
  15. IrishPower

    Calculation of Touch and Step Voltage Limits using EN50522

    radug, Thanks again for the useful information. I wasn't aware that there were similar touch and step voltage criteria listed in standard EN50341 (for overhead lines) and in standard 50122 (for railways). As you say, it makes sense that similar criteria should be used for other types of high...
  16. IrishPower

    Calculation of Touch and Step Voltage Limits using EN50522

    radug, thanks for the information. Maybe by delving in more detail into the other standards you listed we'll be able to work out how the EN50522 limits were calculated. If I've any success I'll post the results here. I had noticed that EN50522 (approved/dated November 2010) specifically states...
  17. IrishPower

    Calculation of Touch and Step Voltage Limits using EN50522

    Thanks Scotty, At present in Ireland the Transmission System Operator (Eirgrid)and the Distribution System Operator (ESB Networks) require use of the IEEE80-2000 standard for design of HV substation earth grids. Some colleagues of mine are presently investigating if (or how) we should move...
  18. IrishPower

    Calculation of Touch and Step Voltage Limits using EN50522

    EN50522 is the new European standard for earthing of power installations exceeding 1kV a.c. The standard outlines the methodology to be followed to select appropriate touch and step voltage safety limits when designing high voltage substation earth grids (covered in Annex A and Annex B of the...

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