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  1. AFerguson

    Outdoor Luminaire Pole System; New Cameras; Grounding Issue

    Multiple luminaire pole system existing with ground rod at each pole. Primary utility service overhead 120V (two conductors only) then run underground in PVC conduit to the poles. Scope is to provide a new camera at each pole, and to provide a bonding conductor between the camera equipment...
  2. AFerguson

    Enphase Inverters / Step-Up Transformer

    System is supposed to be balanced and the inverters have ground-fault protection. Would think this would be sufficient on this separately derived system in this case. You would have a better feel for utility protocol than I - thoughts?
  3. AFerguson

    Enphase Inverters / Step-Up Transformer

    I agree and am waiting on their response. Interesting thing is these units are not really generating their own sine waves and simply track whatever they "see", so the phase shift may not matter from an operational standpoint.
  4. AFerguson

    Enphase Inverters / Step-Up Transformer

    Utility transformer 13.2kV-480Y/277V (wye-wye). Enphase inverter output 208Y/120V; have in-stock a 45kVA 208Y/120V-480V delta transformer. For a normal generator, would assume we would not parallel services; however, the inverter sine waves are controlled by the utility, so would they even care...
  5. AFerguson

    DC conductors interference on PV system

    Array voltage ranges 320-600Vdc.
  6. AFerguson

    DC conductors interference on PV system

    Rooftop PV system approximate size 2MW. Weather station had a lot of signal errors which were blamed on the DC cabling causing interference. Grounding was correct. Cable was installed in PVC, unshielded, and run with 120V power cable approximate distance 150 feet. Problem was solved by...
  7. AFerguson

    PV System Availability Measurements

    Where can I find samples/equations to calculate planned and unplanned outage rates for a utility-scale PV system? Are they inside an IEEE standard? Have seen them for nuclear (much more detailed) but not PV.
  8. AFerguson

    Photovoltaic; Single-Phase Inverter on Three-Phase System

    Multi-tenant (nine meters) warehouse, fed 240V-delta. Three customers use the 240V three-phase service, remaining customers use the 120/240V single-phase service. Three single-phase customers plan to install PV using 240V single-phase inverters. Installation is allowed per NEC 690.63(A)...
  9. AFerguson

    PP4300 Hard Case

    We have a large, non-metallic hard case to house the PP4300, CTs, VTs, power supplies etc., but need a small hardcase that will house a single PP4300 that we can drill holes in for probe and power supply entry. Also would like ability to attach an aircraft cable and padlock to the case. Anyone...
  10. AFerguson

    Suggestions on Choosing a Power Analyzer

    We have 3 PP4300s - Agree that the customer should not see you set them up, but they have produced excellent results when in used combination with the Dran-View software. The PX5 is also a sharp unit and easier to use than the PP4300. Either way, no unit has the "cheeseburger" button!
  11. AFerguson

    Handhole Grounding

    Please provide a link for the handhole detail with a grounded cover.
  12. AFerguson

    Handhole Grounding

    480V, 3W system. Equipment bonding conductor sized per the overcurrent device. Running 3-1/C#2 and 1-1/C#8 GND from source to building via ductbank with handholes. Do we have to bond the rebar in the handholes to the bonding conductor? How could you / is it necessary to ground a metallic cover?
  13. AFerguson

    Substation Design Course

    All, Can anyone recommend a decent substation design course? Thank you for your input.
  14. AFerguson

    Short Circuits Calcs w/ Transformer Taps

    The utility supplied the transformer information and secondary short circuit currents. Normally the secondary SCC would be acceptable, but the model I am creating requires that I develop a primary utility contribution using the given data.
  15. AFerguson

    Short Circuits Calcs w/ Transformer Taps

    Yes, this is a three-phase transformer.
  16. AFerguson

    Short Circuits Calcs w/ Transformer Taps

    Given: 10 MVA, 46 kV - 12.47 kV Transformer Z = 10.4% Primary Tap -2.5% (45 kV) Secondary Tap +5% (13.09 kV) 3P Secondary Short Circuit Current = 4290 A 1P Secondary Short Circuit Current = 4620 A I am trying to determine the utility (primary) short circuit contributions but seem to be missing...
  17. AFerguson

    Series TVSS

    Aside from miscoordination, are there negative effects associated with series connecting two TVSS systems? For example, plugging a UPS with TVSS into a power strip with the same level of TVSS or higher.
  18. AFerguson

    Electrical Training for CAD Staff

    Thank you for the response, but I have already looked for resources on the IEEE website and did not find anything helpful.
  19. AFerguson

    Electrical Training for CAD Staff

    I am trying to locate an online course that will teach basic electric power principles to our CAD operators. There are many books available, but I prefer to have online training coupled with workbook-type materials. Any suggestions would be most appreciated.

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