I don't know the if it's relevant, but there are equivalent circuits for transmission lines that include capacitive and inductive elements. for example pi equivalent for long lines.

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(2B)+(2B)' ?

Thank you electricpete..,
I think it's difficult to control or adjust a required VAR value correlate to PF rectification on the grid when we use transmission cable...cmiiw.

I agree. There's two problems there:

1 - there's no adjustability in the length and therefore no adjustment in equivalent circuit model

2 - the phrase reactive compensation to me implies we're talking about the fundamental so I had in mind fundamental reactive compensation. Trying to use a transmission line for reactive compensation of the fundamental is different than trying to use a transmission line to address (filter?) harmonics, to my way of thinking. I haven't given much thought to the latter and don't feel I could comment on that without more information about what the system looks like and what you are trying to accomplish.

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(2B)+(2B)' ?

A VAR compensator typically adds in steps of compensation to keep the power line power factor within the desired limits.
You may find it difficult to vary the reactance of the transmission line in steps.
Other than that, it is what it is.
Your VAR compensator will compensate for load reactance as well as compensate for the transmission cable reactance.

Bill
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"Why not the best?"
Jimmy Carter

Thanks electricpete and warross for your advices.

Just as the line resistance and line reactance are fixed values (neglecting temperature changes) the line capacitance is a fixed value.
The line capacitance can not be ignored in your design just because it is a fixed value.
You should evaluate the effect of line capacitance on voltage rise when the line is lightly loaded.

Bill
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Ohm's law
Not just a good idea;
It's the LAW!