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National Power lines have come into contact with OLE - Berwick (13/10)

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londonmidland

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It appears the National Power lines have come into contact with the overhead line equipment (OLE) at Berwick-Upon-Tweed, as a result of ‘falling down’, causing severe disruption on the ECML.

Besides the weight of the cables themselves, what damage/what happens when two live power lines come into contact with each other?
 
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pdeaves

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londonmidland said:
It appears the National Power lines have come into contact with the overhead line equipment (OLE) at Berwick-Upon-Tweed, as a result of ‘falling down’, causing severe disruption on the ECML.

Besides the weight of the cables themselves, what damage/what happens when two live power lines come into contact with each other?
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If they happen to be different phases, there would be a massive short circuit. If the National Power lines are at a different (higher) voltage to the OLE then there would also be electrical damage.
 
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800001

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11000 volts in the Nation Grid Wires that fell, the catenary and contact wires are damaged on both up and down lines, there is significant damage with the line closed for the remainder of the day.
 
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hwl

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800001 said:
11000 volts in the Nation Grid Wires that fell, the catenary and contact wires are damaged on both up and down lines, there is significant damage with the line closed for the remainder of the day.
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Usually there is some signalling equipment damage too when power line comes down.
In this case the DNO equipment is more likely to have been fried than NR's.
 
LNW-GW Joint

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Bletchleyite said:
Bang, flash, nasty mess? Possibly damaged substations etc?
Hope the diesels on those 80xs are working! :)
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Seemingly no clever diversions today, nothing going north of Newcastle.
It's buses or use the WCML.
ECML services already badly disrupted by earlier trespass around Stevenage.
 
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malc-c

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LNW-GW Joint said:
ECML services already badly disrupted by earlier trespass around Stevenage.
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Sadly it was a fatality at Stevenage

A person has sadly died after being 'struck by a train' this morning in Hertfordshire, with a number of services cancelled.

Emergency services have been dealing with an incident at Stevenage railway station since 11am today (Tuesday, October 13).

The London North Eastern Railway service between Kings Cross and Peterborough has been temporarily suspended after police found a casualty on the tracks.
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https://www.hertfordshiremercury.co...live-great-northern-updates-stevenage-4601649
 
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800001 said:
11000 volts in the Nation Grid Wires that fell, the catenary and contact wires are damaged on both up and down lines, there is significant damage with the line closed for the remainder of the day.
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Local distribution network stuff. 11000 volts is way below National Grid‘s area of responsibility.
 
Whistler40145

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As a matter of interest, where is the ECML OHLE fed from in the Berwick upon Tweed area and which voltage National Grid supply is used?
 
Philip Phlopp

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Domh245 said:
I presume that failure was electrically induced rather than mechanical?
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I'd guess both - electrically induced partial failure at the immediate point and time of contact, pretty much immediately followed by a tension induced mechanical separation of the cable.
 
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D365 said:
That's one of my lifelong questions answered; what happens when Network Rail and National Grid get too close for comfort...
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Second time this month the previous one involved DNO cables falling in 3rd rail land - just the signalling (track circuit) fried then.
 
59CosG95

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swt_passenger said:
(area) Distribution Network Operator. These are the successors to the regional electricity companies.
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Indeed so. A map of the DNOs is included below:
1602669263793.png

National Grid, meanwhile, is England & Wales' TNO (Transmission Network Operator), and have higher voltages to reduce heat losses (275kV/400kV); heat losses are caused by higher currents.
 
najaB

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59CosG95 said:
and have higher voltages to reduce heat losses (275kV/400kV); heat losses are caused by higher currents.
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Just for completeness...

Ohm's law states V (voltage) = I (current) * R (resistance). Rearranging that gives you: I = V/R - meaning that, for a given value of R, as V gets larger I gets smaller.

Which is why the National Grid operates at hundreds of kV since the resistance in hundreds of miles of transmission cable is quite significant. It's also why we use 25kV for OHLE, it's a nice compromise between reducing losses and having reasonable safety margins for avoiding shock risks.
 
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MadMac said:
Isn’t there a feeder at Marshall Meadows, right around the border?
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Getting slightly off topic here, but yes there is, the railway end of the feeder is at Marshall Meadows, IIRC it comes from the grid supply over to the South West near Eccles. It’s one of the weaker supplies on the ECML which is why it’s being strengthened as part of the ongoing power upgrade - as is discussed in a thread in the infrastructure forum.
Whistler40145 said:
As a matter of interest, where is the ECML OHLE fed from in the Berwick upon Tweed area and which voltage National Grid supply is used?
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Looking at Google Streetview there are fairly simple wooden posts leading away from the site in the SW direction, I think that’ll be 132kV? Or see later it’s probably 33kV. They seem to head for the Berwick area substation near Low Cocklaws, then there’s a bigger overhead line to the Eccles Grid site.
 
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swt_passenger said:
Getting slightly off topic here, but yes there is, the railway end of the feeder is at Marshall Meadows, IIRC it comes from the grid supply over to the South West near Eccles. It’s one of the weaker supplies on the ECML which is why it’s being strengthened as part of the ongoing power upgrade - as is discussed in a thread in the infrastructure forum.

Looking at Google Streetview there are fairly simple wooden posts leading away from the site in the SW direction, I think that’ll be 132kV? They seem to head for the Berwick area substation near Low Cocklaws, then there’s a bigger overhead line to the Eccles Grid site.
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The Eccles in question being about 10 miles SW of Berwick I presume, unless the Great Extension Lead in Manchester has just got a lot greater.

Posted above that it was just 11kV - I think 132kV would be on pylons not wooden poles.
 
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edwin_m said:
The Eccles in question being about 10 miles SW of Berwick I presume, unless the Great Extension Lead in Manchester has just got a lot greater.

Posted above that it was just 11kV - I think 132kV would be on pylons not wooden poles.
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Just found a useful mapping resource, “openinframap”. They reckon it’s 33kV supply to Marshall Meadows, I’ll amend my earlier post. Just to clarify, we’d “thread drifted” onto the supply to Marshall Meadows, AIUI not relevant to the local distribution cables where the fault occurred.
 
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Edinburgh2000

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najaB said:
Ohm's law states V (voltage) = I (current) * R (resistance). Rearranging that gives you: I = V/R - meaning that, for a given value of R, as V gets larger I gets smaller.
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Not quite! For a fixed resistance, as V gets larger, I gets larger too.

I think what you meant is that for a fixed power, the current is less and so the losses are less. Power= V*I so, if V is greater then, for the same power, I is less. The (resistive) losses are I^2 * R, so increase with the square of the current. (With alternating current the impedance is not just the resistance, but that's another matter!)
 
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