Effect of conductor orientation on transmission line ampacity

In summary, the orientation of the conductor relative to North will change the ampacity of the transmission line.
  • #1
MrBuggy
1
0
Hi guys,

I was playing around with conductor configurations and observed this phenomenon. Mind you these are for the High voltage transmission (138 kV) lines that span kms. So apparently, the orientation of the conductor relative to North will change the ampacity of the transmission line. Can anyone explain to me why this is the case? I mean it makes sense to me how the wind, elevation, latitude and etc. would affect ampacity as it tells us the sag, and how the sun hits the conductor.

Thanks,
MrBuggy
 

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  • #2
Hmmmm...good question. Here's a random, somewhat educated guess:

I know there some giant magnetic field in regards to the Earth. Also being parallel with the poles (north) as opposed to being perpendiclar to poles (East, West) must have some effect on the wire.

If there is some rotating magnetic field from the poles or somewhere else, that can increase or decrease current flow.
Now someone really smart can answer:)
 
  • #3
The line direction determines, in part, the amount of solar radiation received by a given conductor. It is used to
calculate the angle of incidence of solar radiation. EDSA provides two choices for line direction: north-south
and east-west. Line direction is normally a parameter of little interest. If you use a sun time of noon for your conductor evaluations, you will find that an assumed East-West orientation will yield a slightly more conservative result than an assumed North-South orientation. If you use an other sun time between 10 A.M. and 2 P.M., an
assumed East-West orientation will yield a slightly more conservative rating unless your latitude exceeds
roughly 55 degrees north, where an assumed North-South orientation becomes slightly more conservative.
Obviously, if you select ‘Night’ as your sun time, it makes no difference what you select for line direction.

http://www.poweranalytics.com/designbase/pdf/Bare_Wire_Sizing.pdf [Broken] page 12.

For example when the sun is due south, an E-W line "sees" more sunlight per unit length of line than a N-S line, unless the sun is directly overhead.
 
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  • #4
Or it could have absolutely nothing to do with the magnetic field and everything to do with the angle of the sun.
Missed it by that much...
 
  • #5
At 1kW/sqm, there's a lot of power falling on a long line; makes you think. That's another thing I just learned on PF.
 

1. What is conductor orientation and how does it affect ampacity?

Conductor orientation refers to the direction in which the conductors are installed on a transmission line. It can significantly impact the ampacity, or the maximum amount of current that can flow through the conductor without exceeding its temperature rating. The orientation affects the amount of heat dissipation and the resulting resistance, which can impact the ampacity of the transmission line.

2. How does the placement of conductors affect their orientation and ampacity?

The placement of conductors on a transmission line is also known as the phase configuration. Different phase configurations, such as vertical, horizontal, or bundled, can impact the conductor orientation and ultimately the ampacity. For example, bundled conductors have a lower ampacity compared to vertically arranged conductors due to increased heating and resistance.

3. What are the factors that determine the optimal conductor orientation for maximum ampacity?

The optimal conductor orientation for maximum ampacity depends on various factors such as the ambient temperature, wind speed, distance between conductors, and thermal characteristics of the conductors. Generally, the horizontal orientation is more suitable for areas with high wind speeds, while the vertical orientation is better for areas with high temperatures.

4. How do changes in weather conditions affect conductor orientation and ampacity?

Changes in weather conditions can significantly impact conductor orientation and ampacity. For instance, high temperatures can cause conductors to sag, affecting their orientation and ampacity. Similarly, strong winds can cause the conductors to sway, which can impact their orientation and ampacity. It is essential to consider these factors when designing a transmission line to ensure maximum efficiency.

5. Are there any safety concerns associated with conductor orientation and ampacity?

Yes, there can be safety concerns associated with conductor orientation and ampacity. Conductors operating at their maximum ampacity may generate excessive heat, which can lead to sagging or even failure of the transmission line. It is crucial to consider the optimal conductor orientation to prevent potential safety hazards and ensure the reliability of the transmission line.

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