X / R Ratios for Transmission Lines

You need to determine the X factor for the transmission line. Generally the MFG can give you some basic information regarding resistance and reactance. Spacing of the conductors comes into play in determining the conductor reactance.

X/5 ?

No, 5 is the descriptive system ratio. Eg_ 5=X/R

For a transmission line, R should be known as it is a function of the resistance per unit length (metre or foot). If you don't know the type of conductor and its cross sectional area (or better yet have a data sheet for the conductor in question) then R cannot be calculated.

dear,

x/r ratio is sufficient for other required engineering calculations /

Generally, manufacturer gives all details of x & r per km for each specific size of the conductor.

hai normally u have 3 specification parameters in transmission line 1. short circuit KVA or Isc, 2. line to line voltage (VL), 3. X/R ratio.

from short circuit KVA and VL you can find out impedance(Z).

Z= sqr(VLL)/(s.c KVA*1000)

now you can find out R. R= Z/(sqrt(1+sqr(X/R)))

hoping that this will help you

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