ECML Power Supply Upgrade

Discussion in 'Infrastructure & Stations' started by 59CosG95, 27 Aug 2019.

  1. edwin_m

    edwin_m Veteran Member

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    But would the smaller but more numerous feeder stations actually be cheaper in areas where there is a suitable grid connection to build a large one?
     
  2. swt_passenger

    swt_passenger Veteran Member

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    There must be pretty huge advantages for the supply and distribution side, as you lose the mis-balance between phases which is typical of existing supplies.

    There’ll probably be an element of ‘not invented here’ to get past, I expect.
     
  3. edwin_m

    edwin_m Veteran Member

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    I think that's the reason it can work on lower voltage feeders where the phase imbalance would be too big relative to the capacity of the supply.
     
  4. aleggatta

    aleggatta Member

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    This is interesting! I wonder if there is the capacity(now or in future) for the DNO to 'mix' the balance of the supply in real time at these types of feeders to balance the overall three phase system in the local area? a win-win for all concerned if it is possible!
     
  5. GRALISTAIR

    GRALISTAIR Established Member

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    Electrical engineering is improving all the time so I do have high hopes for further improvements.
     
  6. hwl

    hwl Established Member

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    The new 400kV grid supplies also use all 3 phases*. This a big difference from the old 132kV ones

    *Connecting them up and earthing them is very different which caused Alstom some grief at Pudding Mill Lane and Kensal Gas work feeders while connecting up the new co-located pairs of Crossrail and NR feeds (Twin independent 400kV feeds at each).

    400kV has many advantages if there is a convenient substation next to /near by the line (e.g. Kensal (ex-) Gas Works) but the costs can be huge if there isn't a suitable 400KV supply let alone substation.
    The new approach also means you need a spare 33kV DNO circuit which can also be a rare as hen's teeth in some areas you want to electrify or reinforce.
    South Wales has plenty of easy 400kV supply opportunities.
     
  7. swt_passenger

    swt_passenger Veteran Member

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    AIUI the problem in north Northumberland always was the lack of a useful grid supply, of any description, as there was no significant population or industry to justify a major supply for non-railway purposes. The supply from Lynemouth power station was apparently poor quality because it’s normal base load was the Alcan smelter.
     
  8. hwl

    hwl Established Member

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    Similarly there is nothing much (Grid or spare DNO circuits) in large parts of east Sussex hence part of the reason Uckfield has never been electrified.
     
  9. InOban

    InOban Established Member

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    This may not be relevant to this thread, but I was past Longniddry at the weekend and noticed a new concrete pad just to the East of the station. Anyone know what for? I wondered whether it was a sectioning cabin?
     
  10. swt_passenger

    swt_passenger Veteran Member

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    The first post lists a new “ASP” at Longniddry - but that’s an abbreviation not explained yet. Perhaps it’s Ancillary Supply Point, but don’t quote me. Otherwise Longniddry is listed as a Mid Point Track Sectioning Cabin (MPTSC).
     
  11. 59CosG95

    59CosG95 Established Member

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    Longniddry is still an MPTSC, but the ASP is indeed an Ancillary Supply Point. AmcoGiffen were contracted to install new signalling power supplies at all interlockings from Edinburgh to Berwick, and an Ancillary Supply Point is the TSC 'equivalent' (as I understand it) of the signalling power supply network.

    Principal Supply Points (PSPs) are the equivalent of feeder stations, and are different from PSBs which either mean Power Signal Box or Panel Signal Box! (it's wrecked my head a few times I can tell you)
     
  12. swt_passenger

    swt_passenger Veteran Member

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    Thanks for explaining. So are the alterations or additions to signalling PSPs and ASPs a necessary part of the whole upgrade, or is it more like a sensible time to do the work, while civils and electrical contractors are around anyway?
     
  13. 59CosG95

    59CosG95 Established Member

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    As the works were undertaken in 2017, I think it was a case of "while you're here..." for AmcoGiffen. It might have been a small part of the signalling power supply upgrade, which may or may not be separate to the traction power supply upgrade. I don't know for certain as I'm not on either project!
     
  14. swt_passenger

    swt_passenger Veteran Member

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    Found an AmcoGiffen web page describing their work:
    they report that it’s IEP related.
     
  15. HSTEd

    HSTEd Established Member

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    There is also the advantage that if all substations were connected through SFCs, you can potentially operate with all 25kV systems in parallel in the style of DC systems.
     
  16. Roger B

    Roger B Member

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    That sounds as though it could be a big step forward, although I'm not that clued-up on high voltage engineering. It would be really helpful if you could perhaps give an example or two of where this would make a difference, and why. Many thanks
     
  17. HSTEd

    HSTEd Established Member

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    This would make it possible to share demand from trains on a route with all substations on the route.
    Indeed with clever design and control of the static converters you can share demand between substations to maximise utilisation of capacity and even in response to general grid loading conditions.
     
  18. Elecman

    Elecman Established Member

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    How would you control the prospective fault current levels in this interconnected HV system?
     
  19. Roger B

    Roger B Member

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    Thanks HSTEd. Sounds like the way forward. Presumably there's a "but" somewhere, with "but it's expensive" being my first guess, with "but implementation is disruptive and requires lengthy possessions" being my second. What is standing in the way of rolling this out?
     
  20. HSTEd

    HSTEd Established Member

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    The SFCs are more able to control fault currents than regular equipment, by virtue of having total control of the phase, voltage and current flow through the converter.

    Also things like superconducting fault current limiting devices.

    It only really became practical relatively recently thanks to advances in power electronics.
    We shall have to see how things go.
     

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