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Anonymous Poster #1

Ice Loading on Transmission Lines

09/22/2018 7:45 AM

How are these two criteria of India and UK equivalent? Further, what is the meaning of 'In India - there is no ice loading on lines'? (As per CBIP manual - icing is not considered. Is this the meaning of - in india there is no ice loading on lines?)

In India, there is no ice loading on the lines.

(a) Heavy loading is taken as 147 kg/m2 wind pressure;

Medium loading 98 kg/m2 wind pressure;

Light loading 73 kg/m2 wind pressure.'

In the UK,

(a) heavy loading is 0.952 cm ice covering and 39 kg/m2 wind pressure

(b) medium loading is 0.476 cm ice covering and 39 kg/m2 wind pressure

(c) light loading is 39 kg/m2 wind pressure.

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Guru

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#1

Re: Ice Loading on Transmishttps://www.mapsofindia.com/maps/india/annualtemperature.htmion Lines

09/22/2018 9:40 AM

Obviously, light, medium, and heavy are descriptive terms that mean different things in the two countries. Most of India is too warm to worry about icing.

https://www.mapsofindia.com/maps/india/annualtemperature.htm

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Guru

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#2

Re: Ice Loading on Transmission Lines

09/22/2018 10:22 AM

In explanation...

Reference link...

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Guru
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#3

Re: Ice Loading on Transmission Lines

09/22/2018 12:01 PM

0.952 cm, eh? Why not 0.951 or 0.953, or better yet simply 1.0? Who could ever achieve such precision in the field, anyway?

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Guru

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#4
In reply to #3

Re: Ice Loading on Transmission Lines

09/22/2018 12:42 PM

.952 cm = 3/8 inch, probably.

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#5
In reply to #3

Re: Ice Loading on Transmission Lines

09/22/2018 11:23 PM

Maybe this is a "hard" conversion from American specs (ASCE?) to metric? Since the American spec may be a SWAG method, a bit of rounding on the conversion would seems to be reasonable.

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#6

Re: Ice Loading on Transmission Lines

09/22/2018 11:32 PM

When I was doing this stuff, I think we would get 3 loading conditions out of this: Ice, Wind on a different icing condition, wind (hurricane), and maybe others such as a broken wire. Of course the different loadings are going to change the line tension which would affect corner poles. The electric company would give the loading conditions to the pole designer. It was surprising how much the tension would go down if the broken wire condition was on a pole with a suspension insulator (as opposed to a dead end connection.) Adding the suspension insulator length to the line length caused the tension to reduce a bunch!

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#7

Re: Ice Loading on Transmission Lines

09/24/2018 3:17 AM

A1) They are not equivalent.

A2) Most of India is too warm to consider icing.

Consider also that the lines themselves will be running generally above ambient temperature due to i2R losses and insolation.

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