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Shutting Off Power to Prevent Wildfires U.S.A.

Zoomup
Not to reduce pollution or because of excessive demand, is it? Deliberate disconnection of power in cold weather to prevent wildfires apparently in CA.

 
GeologyJim

 
June 11, 2019 at 11:11 am

"Is this now to become “the new normal”? – – Shut off power to paying customers when “models show” something weather-ish might cause power surges, voltage spikes, transformer incidents, and potential fire initiation?



Could any of this ephemeral risk possibly be attributed to a bad mix of unreliable green electricity with sustainable fossil/nuclear-fueled base-load electricity? Or bad forest-management practices that restrict removal of tree/shrub fuel along transmission-line corridors?



California is leading the way toward 13th century lifestyles. Ain’t gonna turn out well".


More.....https://abcnews.go.com/US/pge-shut-power-california-residents-fire-season-underway/story?id=63573625


Z.





  • 0
    I do wonder given the way the US system is organised, if they find it much harder to detect a fallen HV cable While in Europe generally we do not distribute the HV neutral or permit unbalanced loads, so it is possible to knock the HV off smartly when a cable fault to ground, this is not generally possible if loads to neutral are permitted by design.

    Clearly a sizzling HV feed setting fire to a nearby tree, or burning off the grass, is a serious problem.

    It may be that the LV side is a problem too, but I'd expect that to be lower energy.
  • 0
    AFAIK, the problem is not the lines falling, which would soon be detected by loss of supply if not by any more sophisticated means.

    The problems is overhead lines drooping or sagging as the wires stretch in high ambient temperatures and under heavy loading. Combined with lack of tree felling or pruning, the conductors touch the vegetation or get within arcing distance.

    Dry trees etc have a high resistance and only a limited current passes, but enough to start a fire. 0.1 amp at HV is still several kilowatts. Even 10ma can start a fire.


    The answer is of course to put the lines high enough up, and to cut back encroaching vegetation.
  • Former Community Member
    0 Former Community Member

    broadgage:

    The answer is of course to put the lines high enough up, and to cut back encroaching vegetation.




     

    OMG - you can't possible put things up high - it spoils the view  - and, if you cut the vegetation with hate, not love, you'll hear is screaming


    Welcome to generation snowflake


    OMS
  • 0

    mapj1:

    I do wonder given the way the US system is organised, if they find it much harder to detect a fallen HV cable While in Europe generally we do not distribute the HV neutral or permit unbalanced loads, so it is possible to knock the HV off smartly when a cable fault to ground, this is not generally possible if loads to neutral are permitted by design.




    Oddly, while resident in California, I noticed something odd, the transformers are generally connected phase to phase, even in single phase, whereas the rest of the USA generally has a single HV bushing with the return to what we'd call the PEN. Worth looking out for in Hollyweird movies too, they often use trannies with 2 HV bushings even in stuff allegedly set outside Calif, because movies.


    But banter aside, I did wonder at the time if this was possibly to make earth faults more detectable. If not, it seems it could easily be adapted to do so.


    Oddly they DO still distribute the neutral, usually identified with a spraypainted N on the crossarm and sometimes a white insulator.

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