Help w/ power losses on transmission lines
Help w/ power losses on transmission lines
(OP)
I'm not a power engineer, but I've been asked to provide another group in my company a "rule of thumb" they could use to characterize power loss on a high voltage power line, i.e. what's a reasonable power loss (%) per 100 miles on a well designed transmission line?






RE: Help w/ power losses on transmission lines
RE: Help w/ power losses on transmission lines
The equation for dielectric loss from the Neher McGrath paper on calculation of temperature rise of cables (IEEE Transactions Oct. 1957 - there have been some updates to this, too) is:
Wd = 0.00276(E^2)(SIC)(insulation PF) / log[(2T+Dc)/Dc]
Where:
Wd is dielectric loss in watts per conductor foot,
E is phase to neutral voltage in kV,
SIC is relative dielectric constant of the insulation material,
Insulation PF is the power factor of the insulation material (also called tangent delta),
T is the insulation thickness,
Dc is the diameter of the conductor (over the semicon shield).
RE: Help w/ power losses on transmission lines
Loss = 3R x squareI, in Watts
where
R is total resistance of one conductor
I is conductor current
or
Percent Loss = 173 x r x s x I/(E x cos(phi))
where
r is conductor resistance per mile
s is transmission distance in miles
I is conductor current
E is line voltage at receiving end
cos(phi) is power factor at receiving end
Reference:
Electrical Transmission and Distribution Reference Book, Westinghouse Electric Corporation, 777 Penn Center Blvd, Pittsburgh, PA 15235, 4th Edition, 12th Printing, page 271