Transmission line problem
Assuming that the load is constant power load (the power consumption is not a function of Vr). 

Note that the load is higher than SIL. Hence Vr is going to be less than Vs and adding the capacitor will rise up this voltage.

Let us start from third question to first one,

3- The power delivered to load will be the same (P and Q) as per our assumption. However, the reactive power transmitted will be different as the new capacitor supplies reactive power to the load.

2- The current, you did not mention which current but I will assume it is the receiving current Ir. The current is going to decrease as the receiving voltage will definitely increases when the capacitor is connected and as we assume that the load has constant power (i.e. \$I=S^*/V^*\$).

1- Finally, the phase difference. We have \$P=\frac{Vs VR}{X} sin(\delta)\$ this leads to \$sin(\delta)=\frac{P}{\frac{Vs VR}{X}}\$ as P,X and Vs are constants you can get \$\sin(\delta) \propto \frac{1}{Vr}\$ . As Vr is going to be increased due to the additional capacitor, \$sin(\delta)\$ decreases and hence \$\delta\$ decreases also (as the stable range of operation is \$\delta &lt; 90\$)