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  1. HeinzM

    Ground Fault

    Thanks for your input. If adding a new relay - SEL487 - to look at the 52U and 52F1 breakers, can such protection scheme determine ground fault current direction? Depending on where the fault happens ( 1 or 2 ), we have to trip the correct breaker to separate the fault and keep the loads...
  2. HeinzM

    Ground Fault

    Is anyone able to give me a clear explanation of fault current flow on the attached 1-line with fault locations in case 1 and 2? The incoming utility service is a 13.2 kV delta. The 480V generator is connected with a 13.2 kV wye-gnd to 480 V delta transformer. On a recent utility fault on the...
  3. HeinzM

    Ground Fault on Delta Side of Transformer

    Floating. The inverters do not need the neutral
  4. HeinzM

    Ground Fault on Delta Side of Transformer

    BTW, the inverters were off when the neutral got taken out, so no generation was adding load into the system.
  5. HeinzM

    Ground Fault on Delta Side of Transformer

    Hi, The loads 208/120 are regular power distribution in a school, single phase 120V and 3ph 208 for AC and other equipment. However, there is also a Solar Power system (PV) on the roof with a Wye gnd/ Wye (floating) transformer 208/480V 225kVA. The neutral to this transformer is the one having...
  6. HeinzM

    Ground Fault on Delta Side of Transformer

    We have a 13.2 kV Delta to 208/120 Wye/gnd transformer, supplying facility power. The utility had a single phase ground fault on the 13.2kV primary side and the Neutral conductor on the grounded wye got destroyed/burnt. Any ideas how that neutral conductor picked up extensive current?
  7. HeinzM

    3V0 Detection/Protection

    Yes, Rock. But that's the expense they want to avoid. The PT cabinet measures about 4' (cube), has to be set on a concrete pad, protected by bollards. And the 15kV insulated PTs cost a few bucks, too. And all that for (proven ) clearing of the generation within cycles of losing the line.
  8. HeinzM

    3V0 Detection/Protection

    The utility want to protect against feeding a ground fault on their side. I have no idea how they protect their feeder and under what conditions they trip off line. Besides, the generation source is solar inverters, which are setup according IEEE 1547 and stop when the line is gone. Utility...
  9. HeinzM

    3V0 Detection/Protection

    Gentlemen, can a ground fault on the primary side of a delta/delta main transformer (1MVA, 13200/380) be seen/detected on the secondary side of the transformer? I say, NO. We would like to avoid MV rated PTs to detect a utility ground fault. No high side Wye-G PTs are installed.

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