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Recent content by desrod

  1. desrod

    Power System Analysis for Overload?

    You might want to look at ETAP tutorials to get an idea of the required info. Also, since you are an EIT, why not ask your supervising eng. for pointers? You can always ask questions, in fact that's the right way to do it and as a future professional your are expected to do so to expand your...
  2. desrod

    What's in a GM1004 "ArcTrap"?

    Try the following link: http://www.gai-tronics.com/literature/industrial/gtc070503gm8000.pdf You can even call the guys there, I am sure they can help.
  3. desrod

    Fuse cut-outs on transmission lines tripping the feeder

    Viking, you wrote: "A transient fault caused the fuse to burn out which caused a short that tripped the whole feeder." If there was no other fuse between the feeder breaker and the fault, it is expected that the breaker will clear the fault. If there was one, then as suggested by dpc, you...
  4. desrod

    Fault Clearing Time

    Timm, Usually you will have more than one LV feeder connected to the main transformer and therefore you want the LV breaker to operate before the main breaker (That's coordination). Interesting to note that you now have a fuse protecting the transformer not a breaker. Different configuration...
  5. desrod

    Fault Clearing Time

    Key words here is "protection coordination". If you are not familiar with the concept (and the questions you are asking tend to show that), I would suggest that you either ask experienced people to coach and review your work or subcontract the task. In some countries, arc flash studies are to...
  6. desrod

    Trying to get back into Electrical Engineering field - need advice

    You might want to look at the following org:Engineer without borders. I know some colleagues who worked with them in Quebec. You might find a way to merge engineering with idealism. You should find interesting projects and you will have a chance to refresh your knowledge...
  7. desrod

    Calculating length of wire in existing electromagnet

    How much precision do you need? What instrument(s) do you have? Measure the Rdc of the electromagnet and find the Rdc per meter of conductor (measure or get it from reference tables). The ratio gives you the total lenght. This should give you a good estimate.
  8. desrod

    Etap problem, always crash when I add data in transient stability editor

    That's the kind of problem that should be covered by your maintenance contract with ETAP. Send that directly to them. They should solve the problem rapidly.
  9. desrod

    Load Flow Model Limitation

    Distribution system losses level should be less than 10% at peak (typical average 3-4% in North America). How is your network behaving in its normal configuration? What is your MV level? Be aware that some software will switch load model when voltage reaches a certain threshold. We recently...
  10. desrod

    Harmonic Analysis: sources to measure and for how long (and other questions!)

    Harmonics studies are tricky. I always use experienced teams to make measurements and I try to have measurements prior or without the new equipment to get a proper assessment of the background harmonics especially if I am designing the filters. Depending on the supply network, there is a risk...
  11. desrod

    Motor Supply Voltage and Performance

    Also consider cost of labor since qualifications for working at 6.6 kV vs 0.525 kV is different in some jurisdictions.
  12. desrod

    Asking about Basic of Software ETAP

    You can check the web for references. There are a number of good books you might be able to get at your school or company library.I would have given you some title but they are likely out of the market since I finish eng school 35 years ago. I don't use ETAP so I am not aware of their training...
  13. desrod

    Inverters as Feeder Circuit Source

    We perform network impact studies and distributed generation (DG) modeling and so far, most DC coupled generation we worked with, had fault around 1.05-1.1 current pu. I think there was one manufacturer that mentioned 1.2 p.u. but it was never confirmed. For a manufacturer view it makes sense...
  14. desrod

    Asking about Basic of Software ETAP

    There are a lot of missing data that you forgot to consider/show. How did you model your motor? Nominal voltage? PF? all that will influence your load-flow. What is the impedance of your transformer? size? I would recommend that you do the load-flow by hand and then check with your simulation...
  15. desrod

    Dynamic model in PSS/E

    Many wind turbine manufacturers provide PSS/E model to use for your studies. You should ask them directly. Otherwise, pick a generic model close to the technology.

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