Sizing of a fixed shunt capacitor

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Dear All

I want to size my Fixed shunt capacitor based on my loadflow: so say my Capacitor is 300 MVAr but the initial loadflow voltage is 1.05,Thus I want to re-size my MSC as Q/V^2 (almost a constant Q).

I would like to do this in python: i got to the stage of using psspy.shunt_chng of

psspy.shuntchng(153,r"""1""",i,[_f, 300.0/(voltage)**2])

but I do not know know how to obtain a single voltage value for the desired bus which in this case is 153. All I want is to obtain (recall) a numerical value for the given bus so this formula works, but I do not want to type it in.

Can someone help me? Also I would like to do this in array for a larger system but once I prove this simple calculation in python.