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Recent content by System Protection

  1. System Protection

    Transmission ground distance relaying with distribution underbuild

    Any chance this started as a distribution fault? Could explain the prefault. I remember seeing some strange prefault waveforms and it was due to the underbuilt distribution faulting first. Or perhaps evolving into a transmission to distribution fault?
  2. System Protection

    Transmission ground distance relaying with distribution underbuild

    Another fault location method is to compare the ratio of 3I0 current from each end of the line. That should help account for fault resistance. You would use Synchrowave to get the 3I0 current from each end. Divide one end by the other. Then run intermittent faults in your fault sim program...
  3. System Protection

    Transmission ground distance relaying with distribution underbuild

    How are you finding the best fit with your fault program? Could the fault resistance be the reason your Z0 seems low?
  4. System Protection

    Transmission ground distance relaying with distribution underbuild

    Typical would be 85% reach for Phase distance and 70% reach for Ground distance for Z1.
  5. System Protection

    Transmission ground distance relaying with distribution underbuild

    I model it all in the line constants program that I use as its not much more effort to add the underbuild. But I don't input the mutual impedance between transmission conductors and underbuild into my fault sim program as the distribution system is not modeled. Definitely would recommend...
  6. System Protection

    Semi Hauling Excavator Hits Bridge over I-10 in New Mexico

    I checked a random spot on I10 on Street View and it showed 75MPH without a separate speed for trucks.
  7. System Protection

    Wait to reenergize following lightning?

    Single Phase Auto Reclosing I don't think its that common below 500kV. At least that I've seen in the USA.
  8. System Protection

    Things you love/hate with mathcad

    I'll add another MC Prime annoyance. If you are paging up and your cursor lands in a text box you will enter in it and will have to click outside of the box to continue paging up.
  9. System Protection

    Wait to reenergize following lightning?

    This makes sense. Maybe their policy got lost in translation somewhere.
  10. System Protection

    Wait to reenergize following lightning?

    Nope. What would they do if a significant portion of their lines got hit with lightning? Just leave half their lines out of service? Its normal to go inspect a line that trips to lockout before attempting to re-energize but I've never seen one left de-energized after the problem was found/fixed.
  11. System Protection

    Help a non-PLC guy with this control application

    Schweitzer Engineering Laboratories (SEL) has automation controllers. (SEL-2411 for example) They are more utility focused. But their support is amazing and programming them is quite simple.
  12. System Protection

    Cylinder Deactivation

    I've had this one bookmarked for awhile for the next time I needed a automotive connector: https://connectorexperts.com/ Have not used it myself. Otherwise, I just use Deutsch connectors.
  13. System Protection

    Nuisance tripping in Sepam T40

    I agree with thermionic1, that is the first thing I'd check. Here is the NERC lessons learned overview of the issue. https://www.nerc.com/pa/rrm/ea/Lessons%20Learned%20Document%20Library/LL20130703_Use_Loading_Resistors_when_applying_solid_state_contacts.pdf I've seen it quite of few times...
  14. System Protection

    Running a DOL starter from a VFD

    His 230V supply is single phase and 50hz. He is trying to perform testing from the UK. After installation the source voltage will be the necessary 230V 3 phase 60hz.
  15. System Protection

    Back for another burst

    I think you will like it after you get used to it a bit.

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