Per Unit Susceptance

[Marmite]

I've been asked to provide some system planning data for the transmission company relating to a new 66/11kV substation including the circuit electrical characteristics for the 66kV cables feeding the new transformers.
The information required is per unit positive and zero sequence resistance, reactance and susceptance.
In this context, what is the susceptance? I'm sure its not just the inverse of the reactance otherwise I wouldn't need to provide it as a separate figure. What is the susceptance figure useful for in system modelling?
Thanks in anticipation.
Regards
Marmite

 

[m3ntosan]

Practical example:

Susceptance for a 750 kV OHL, Bo ~ 3.9 * 10 -6 S/km

Reactive power produced by the OHL energized from one end:

Q = Bo * (U*U) * L ~ 220 Mvar/km

Bo = S/km
U = kV
L = km

May you grow up to be righteous, may you grow up to be true...

 

[davidbeach]

Susceptance will be the inverse of the shunt reactance, while the impedance will be the series impedances. Generally, and in this case, susceptance will be the capacitances. It is easier to deal in susceptance than capacitive reactance because the susceptance will be proportional to length while the capacitive reactance is inversely proportional to length.

 

[Marmite]

Thanks Guys.
I appreciate the answers.
Regards
Marmite