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  • Users: davidbeach
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  1. davidbeach

    Free(ish) to a Good Home

    I need to be reducing my library for an eventual move to smaller quarters. There's a couple of groups of books that I can easily part with, but really hate to just dump them into the recycling. First is ten years worth (1983-1992) of the Hewlett Packard Electronic Instruments and Systems...
  2. davidbeach

    Odd Substation Corrosion

    At one substation we've noticed that on multiple two-legged three-phase stands for the 115kV equipment there is the appearance of corrosion between B- and C-phases. Nothing apparent between A- and B-phases. As can be seen, it isn't just one support structure, and it has a hard edge at...
  3. davidbeach

    3000A 230kV Getaway Cable

    Anybody have any experience with anything along the lines of a 3000A 230kV insulated cable run? Not that it's the best solution, but what somebody might get backed into. Overhead seems to be off the table at the moment even if it might be a better solution; lets just say we got backed into...
  4. davidbeach

    Fiber to the Yard

    Anybody done a merging unit substation? Either an IEC 61850 based design or a proprietary scheme like SEL's TiDL? I see a possibility to save a bunch of wiring installation and checkout time with something that seems more plug and play than conventional wiring, but also see a huge paradigm...
  5. davidbeach

    Ferroresonance

    Does anybody have experience with a transformer being damaged by ferroresonance? Particularly where the condition was interrupted fairly quickly and failure wasn't catastrophic? I don't yet know the details of the transformer failure, but apparently there was considerable current when it was...
  6. davidbeach

    UK Grid problems 9th Aug - Follow Up

    Reference thread815-456677 NERC has issued a Lessons Learned based on this event. See https://www.nerc.com/pa/rrm/ea/Lessons%20Learned%20Document%20Library/LL20201001_Single_Phase_Fault_Precipitates_Loss_of_Generation_and_Load.pdf
  7. davidbeach

    NERC Lessons Learned

    Good reading to be found at https://www.nerc.com/pa/rrm/ea/Pages/Lessons-Learned.aspx. The two "https://www.nerc.com/pa/rrm/ea/Pages/Lessons-Learned.aspx" have both been discussed here. Glad they were somebody else's problems and not mine.
  8. davidbeach

    GE IJD14B Relay

    Looking for somebody with some really old notes. I'm trying to understand the operation of a GEIJD14B relay; the instruction bulletins (both GEH-931 from April 1934 and GEH-1151B with no date) have a description of operation that seems to require the knowledge of how many turns of the operate...
  9. davidbeach

    VBA in Outlook

    I've done a fair amount of VBA programming in excel but haven't tried doing so in Outlook yet. I receive a bunch of automatically generated emails that all arrive with a single attachment. What I'd like is to take a folder in outlook that contains a group of these emails and extract the...
  10. davidbeach

    Transformer "Grounded" Through an Arrestor

    I think I've run into this more than just this once, where a wye-delta transformer is installed with the wye side H0 or X0 bushing connected to an arrestor rather than either a grounding impedance or a solid ground. For now I've got one to consider how to represent in our OneLiner model. We...
  11. davidbeach

    Substations - Rock vs. Grass

    I just got back from nearly three weeks in Italy (and a bit in Switzerland) and I saw lots of substations with grass or other vegetation throughout. What I’m used to is a high resistance rock surface to limit step and touch potentials. I can’t imagine wet grass having nearly as high a...
  12. davidbeach

    Conflicting desires in a transformer...

    Historically we've stepped down from transmission/sub-transmission to distribution voltages with delta-wye transformers with the low-side wye solidly grounded. Worked great for decades. Still works great for much of the system. But, we're seeing increasing amounts of distribution connected...
  13. davidbeach

    VBA Broken under Windows 10?

    Just starting to get my feet wet with Windows 10. One VBA routing I have been using since XP includes the line: PathFile = Application.GetOpenFilename("AcSELerator Export Files (*.txt), *.txt") That has always produced a file open dialog box and returned a string with the path and file name...
  14. davidbeach

    Time to the millisecond

    I may have asked this before, but if I did I never got a workable answer so I'll try again... I need to work with times to the nearest millisecond (and can foresee microsecond times at some point in the future) as I establish times and reference times for events on the electric grid. I can...
  15. davidbeach

    DER exceeding transformer load

    Our distribution system is a pretty normal North American system where the transmission/sub-transmission system feeds the delta winding of the delta-wye transformer(s) in the substations and distribution feeders extend outward as radial load serving, multi-grounded neutral, feeders. Just like...
  16. davidbeach

    View Only excel?

    Is there a way of protecting an excel (2010) spreadsheet so that it becomes view only to anybody else? A quick google search doesn't turn up anything. I have data to share, but it becomes stale very quickly and others in the organization have a tendency to print something out once and refer to...
  17. davidbeach

    CT Misconnection

    I saw a case where a set of there CTs had one wye-point jumper removed. The B-phase and C-phase CTs wound up connected non-polarity to non-polarity and the B- and C-phase polarity sides brought into the control house while the A-phase CT had its polarity wire and the wye-point wire brought into...
  18. davidbeach

    Setting Line Relays Near Generation

    I'm wondering what others do when setting line relays at/near generation, looking onto the system away from the generation. In particular, setting backup protection - the traditional zone 3 or any overcurrent elements. Historically we've essentially ignored the variability and set the relays...
  19. davidbeach

    CT Placement

    We know that when placing a window CT around a conductor that the conductor should be centered in the window and continue straight for some distance beyond the CT. Is there some rule of thumb or standard that addresses what "straight for some distance" means?I
  20. davidbeach

    Core Balance CT Question

    Does anyone have a good reference on how placement of conductors within a Core Balance (Zero Sequence) CT can affect the accuracy? We had a situation where a 480V motor failed. The 480V system is fed from a 7200 V system through a Dyn1 transformer. The feed to the transformer passes through a...

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