In model of short transmission line, only inductance effects gives voltage drop, in medium inductive along with capecitive and long transmission the capacitive dominates inductive effect giving voltage rise...

Unlike shunt capacitor banks FACTS installations let provide smooth control of the voltage level due to change thyristors firing angle.

Regards

My understanding of this problem is a bit different, please correct me if I am wrong. In my understanding, there is a phase mismatch between voltage and current waveforms, introduced as a consequence of a poor power factor (pf). Now, this will mostly be the case when you have inductive loads lets say motors, fans, pumps etc. as there are in the cases of industrial setups.

So in order to improve the power factor, and the phase lag we provide reactive power compensation by using capacitor banks, which in turns provide positive reactive power.

Your constructive feedback/criticism will be welcomed.

Muhammad Ibrahim Munir : There are two different concepts that you mentioned here. One is about voltage support, the other is about power factor. Although both of them affect reactive power consumption /availability in the system. There are slight differences:

(1) In the case of power factor , you are right in your assertion that the load dictates the amount of reactive power consumption. Furthermore, one needs to compensate for the low power factor with additional reactive power sources to correct for the power factor.

(2) In the other case, for voltage support, the reactive power losses might be so high during transmission/distribution that local voltage is not strong (stable) enough to supply any load (both real and reactive, of any power factor). This might lead to a voltage collapse, and hence you need to supply reactive power locally at that bus to compensate for the sag in voltage to be able to supply the local load.