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  1. heberovchem

    Single-phase ground faults and phase to phase ground faults.

    Thank you very much, with those three lines I think I got it now. I do not know why I was making it so difficult. Still, I followed your advice and reviewed symmetrical components again. Hopefully I will be able to explain to someone else if I am asked.
  2. heberovchem

    Single-phase ground faults and phase to phase ground faults.

    Thank you for your feedback, but here is what I meant when I asked the wordy question: in a phase-phase to ground fault (bc fault Vbn and Vcn have same 120 angles, and their magnitude decreases): whereas (bc fault Vbn and Vcn have less than 120 angles and magnitude as before decreases)...
  3. heberovchem

    Single-phase ground faults and phase to phase ground faults.

    I know that a single phase to ground fault causes a rise on the neutral potential, but I need to explain that (why). Is it because there has to be some impedance (even though it could be small) between the neutral and ground (through the return path)? If it is a return path shouldn't the neutral...
  4. heberovchem

    Flex_CT uses

    @ScottyUK Let me see if I understood this correctly: usually mirroring currents through shielding would decrease or change the magnetic flux, which in turn, not only reduces the inductive reactance, but also the magnetic fluxes which will affect the reads on the Rogowski coil. That is why you...
  5. heberovchem

    Flex_CT uses

    @ScottyUK so is the capacitive coupling a possibility in the testing scenario I presented due to the image current the shielding can carry even if the cable is insulated? Could share a diagram or nice website with information on capacitive coupling so I could understand better about the...
  6. heberovchem

    Flex_CT uses

    @GroovyGuy: This is to test 34.5kV three-phase cables (3 wires, delta configuration, and there is no neutral involved). And surely not near lugs or stress-cones (it would be interesting to be sure if it could be done around them, as you brought up). I'd love to hear what bacon4life has to say...
  7. heberovchem

    Flex_CT uses

    Greetings, Thank you @GroovyGuy, this was what I imagined. Now bacon4life got me curious: @bacon4life Aren't most of UG cables shielded, though? Reading upon it, I found that it is to decrease inductive reactance. Follow-up: Do you know how shielding decreases the inductive reactance (I have no...
  8. heberovchem

    Flex_CT uses

    I would like to know what would be the possible safety issues in using a common CAT IV flex-CT (Rogowski) around a 34.5kV insulated cable (not exposed). Theoretically I understand that the amount of current through a 34.5kV is not so high, but during a fault this may change. Is it more of an...
  9. heberovchem

    IEEE 142 calculations

    It is written on page 16. But I've already figured out. Thank you.
  10. heberovchem

    IEEE 142 calculations

    Could someone show me the calculations to arrive at the following percentages: The available ground-fault current should be at least 25% (X0 = 10X1) and preferably 60% (X0 = 3X1) of the three-phase fault current to prevent serious transient overvoltages. Available is considerably higher than the...

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