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  1. txtim

    Guidance on completing an Engineering Degree as mature student?

    I also started my career as a technician (substation testing). I completed my Engineering degree at an ABET accredited college at the age of 33. It's never too late to start. I personally had to make financial arrangements and sacrifices to complete my degree during the day. I attended night...
  2. txtim

    Why would Motor Contributions Not Affect Fault Levels?

    I believe SKM will automatically use the subtransient reactance for a duty rating study and transient reactance for a fault current analysis. As I stated in an earlier post, my experience is limited but as I understand it, the synchronous machines (remember they can be utilized motors or...
  3. txtim

    Formula For Ballpark Transformer Price Calculation

    cirtcele, I am in the utility industry in the South and what we are seeing right now is transformer prices escalating all the time and prices varying wildly between manufacturers, probably due to core steel and copper prices. You need a tight specification and I would suggest (as we do) bid...
  4. txtim

    Why would Motor Contributions Not Affect Fault Levels?

    Allow me to add my two cents. I used SKM to do an analysis several years ago so I'm drawing from memory. When you model your motors, you will input all of the nameplate data including sub-transient and transient reactances (xd' and xd''). When running a breaker duty study, the software will...
  5. txtim

    CCVT Ferroresonance

    scottf, Since the FSD is between the capacitance divider and the base tank, is the CCVT incapable of "backfeeding" potential to the 138kV transmission line? In other words, is it likely that the CCVT capacitance be a significant factor in the equation in the transmission line resonance? I'm...
  6. txtim

    CCVT Ferroresonance

    scottf, I would have (and did) go throgh my regional distributor/rep. No harm, no foul. Thanks for the replies and I will call if I need anything else. regards.
  7. txtim

    CCVT Ferroresonance

    Thanks again scottf. At the risk of offending you, I inquired to Ritz and Trench and only heard back from Trench. Obviously, my inquiry didn't make it through the proper channels (until I joined this forum). You raise an interesting but valuable point on sytstem oscillations and not one that...
  8. txtim

    CCVT Ferroresonance

    Thanks scottf for the reply. Similar questions were asked of me by the vendor when I inquired. We do not have any non-linear loads and I believe the ferro-resonance is actually from line voltage. Another utility is on the remote end and also saw oscillation potential after the breaker(s)...
  9. txtim

    CCVT Ferroresonance

    We have at least two sets of CCVT's that have gone into ferroresonant oscillations after a phase to ground fault. This occurs on breaker and one half configurations where (3) CCVT's are on a line as compared to radial where there is only (1) CCVT on a line. The oscillations are peaking at...

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