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  1. Replies
    112$$
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    Let's say no for the chart that goes along with...

    Let's say no for the chart that goes along with the neutral switching scheme. Now what?

    If you install the device you propose, it is a single point of failure. You claim a single point of...
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    112$$
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    Why does it matter? You won't meet the safe area...

    Why does it matter? You won't meet the safe area on that graph because you are counting on your protective device to not work correctly.

    You don't know that. You don't know how that device is...
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    112$$
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    Pick whatever cycle, kV, ohm, amps you want. If...

    Pick whatever cycle, kV, ohm, amps you want. If you fail to maintain the equipment what have you got? Kinda defeats the purpose of worrying about all the finer details doesn't it?

    Kind of like...
  4. I agree. In service it is an electrode. Abandoned...

    I agree. In service it is an electrode. Abandoned it is buried trash.
  5. Replies
    112$$
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    Either be in the utility business or don't....

    Either be in the utility business or don't. Difficult or not, it is just part of the job.

    Seems odd to stress over NEV during a fault if you are perfectly willing to skip routine maintenance to...
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    112$$
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    But scuffed to operate slower after sitting then...

    But scuffed to operate slower after sitting then operate faster once cycled. If it is sticking it needs work.
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    112$$
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    I agree and those have been my experiences as...

    I agree and those have been my experiences as well.
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    112$$
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    We keep our transmission and distribution...

    We keep our transmission and distribution breakers maintenanced and tested and don't allow the stickiness you evidently are seeing.

    Depends on reach. You would normally want your relay to look...
  9. Replies
    112$$
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    would you believe a breaker rated to open in 3...

    would you believe a breaker rated to open in 3 cycles will open in 3 cycles or less? I know because we routinely test them.

    Then it is malfunctioning and needs repair.

    We don't want to depend...
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    112$$
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    Show me where I said it did. I'm just telling you...

    Show me where I said it did. I'm just telling you what I see in switchgear and fault data.

    Where did your get your number of often more than 5 cycles from? My 2-8 cycles comes from many years of...
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    112$$
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    Yes. There are several other systems around the...

    Yes. There are several other systems around the world and more than one in the US but MGN is the one most used in the US for distribution.
  12. Replies
    112$$
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    Tell me how you propose to set it below shock...

    Tell me how you propose to set it below shock levels on MV system.
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    112$$
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    You don't use a Petersen coil on a MGN system so...

    You don't use a Petersen coil on a MGN system so it is not really relevant.
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    112$$
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    Perhaps you have some setting or breaker...

    Perhaps you have some setting or breaker selection issues. 2-8 cycles is normal total clearing with 5 pretty common.
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    112$$
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    Why thank you Capt. :D

    Why thank you Capt. :D
  16. Replies
    112$$
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    Of course there is. One occurs during a fault...

    Of course there is. One occurs during a fault while protective devices are reacting and the other occurs with no protective devices reacting.

    The kV present during a L-N fault on a MGN should...
  17. Replies
    112$$
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    If you want to change over to discussion of...

    If you want to change over to discussion of faults on ungrounded systems, that is a whole different discussion. Designs for the two are not the same of course.
  18. Replies
    112$$
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    There is a difference between touching a 4 kV...

    There is a difference between touching a 4 kV line while standing on the ground vs. touching a grounded line in contact with a 4 kV line.
  19. Replies
    112$$
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    A Petersen coil tries to cancel the capacitive...

    A Petersen coil tries to cancel the capacitive current on an ungrounded system by paralleling an inductive coil.

    The idea is to keep the current low during transient line to ground faults...
  20. Replies
    112$$
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    Those are for ungrounded systems. We were...

    Those are for ungrounded systems. We were discussing MGN systems.

    What person currents did you calculate and for how long?
  21. Replies
    112$$
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    It must have been determined that the probability...

    It must have been determined that the probability of that happening in conjunctio. with the failure of high-speed clearing is low. I have not researched it.
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    No. But I can design one that will keep you safe...

    No. But I can design one that will keep you safe in a substation if you touch a grounded metal frame that has 4.16 kV impressed on it.
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    112$$
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    Ground Potential Rise Run the numbers and you...

    Ground Potential Rise

    Run the numbers and you will find out differently for a MGN.

    and knowing that I_fault = E / Z, and keeping I_fault the same, and raising E, the Z must increase. Indeed,...
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    112$$
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    We were talking about MGN distribution, not...

    We were talking about MGN distribution, not ungrounded transmission. I used a 3-phase model because it was handy. The mutual impedances with the added B & C phases make a slight difference but not...
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    One example would be equipment on a hill that is...

    One example would be equipment on a hill that is being taken out by lightning surges. Adding grounded arrestors on poles on either side can reduce the failure rate.

    Poor soil (sandy soil) would...
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