Capacitor range is actually given in Kvar, so to find that
range in kvar

As we know
Power factor = KW/KVA
for 65 Hp load
KW= 65HP*0.746 = 48.49KW
Considering Preent P.F=0.50
Target pf =0.99
Multiplying Factor by standard table= 1.59
Kvar= 48.49 KW * 1.59 = 77.09 Kvar

hence for the load of 65hp, capacitor range will be 77.09
Kvar.

as pf not giving ,taking pf 0.8
let pf of load =0.8
kw of load= 65 hp=65*0.746=48.5kw
kva =48.5/0.8=60.625kva
kvar =sqrt(60.625^2-48.5^2)=36.375kvar
if we want to improve pf to 0.95 then
improved kva= 48.5/0.95=51.052
improved kvar= sqrt(51.052^2-48.5^2)=15.9411
requard capacitor range = 36.375-15.94=20.43kvar.

first we should calculate the load(inductive or capacitive
or resistive).
in case of resistive load-----
in case of resistive load the, actual power factor will be
01(maximum),in this case the voltage will linior with
respecte to load current.
so tatal resistive load is(in example 65 hp),
so total load in kw = 65*0.746
=48.49.
As we know
Power factor = KW/KVA
for 65 Hp load(if pure resistive)

Considering Preent P.F=1
Target pf =0.99
Multiplying Factor by standard table= 1.56
Kvar= 48.49 KW * 1.56= 75.64

hence for the load of 65hp, capacitor range will be 75.64
Kvar.(in pure resistor).

If I need to purchase a step-down transformer (from three
phase 33kV 50Hz to 400/230V), what additional information do
I need from the main supply power line?

We have a 33/11kv switchyard having 12.5 MVA power
transformer. We export & import power through this
transformer. When we export power, the PF will be depend on
GRID PF & when we import power the PF will be depend on our
load PF. but the problem is that,when neither we export nor
import but our 33KV vCB is in close position,our meter read
the power factor 0.14 to 0.25 at that moment. So how can be
we improve the power factor at that moment.

Sir, I need a power supply at 380V. The supply I get in
three phase is rated 415V. The total supply I have from the
supply company is 70KW. Kindly inform if it is better to
use a voltage stabiliser for this purpose or a transformer