Question

An infinite bus power system shown below, the generator is delivering the real power of 0.9 p.u. at 0.8 power factor lagging to the infinite bus. The power angle of the generator in degree will be

• A. 20.51°
• B. 26.74°
• C. 18.23
• D. 14.64

Answer 1

The correct option is B 26.74°


Total reactace, X = 0.5 + 0.2 + 0.4 | | 0.4
= 0.5 + 0.4 = 0.90 p.u.
$P=V_{p.u.}\times I_{p.u.}\cos \varphi$

$0.9=1\times I_{p.u}\times \left(0.8\right)$

$I_{p.u.}=\frac{0.9}{0.8}=1.125p.u.$

$E=V+j{I}_a{X}_s$

$=1+1.125\angle -36.86{}^{\circ }\times j\left(0.90\right)$

$=1.607+j0.810=1.79\angle 26.75{}^{\circ }p.u.$

Power angle, $\delta =26.74{}^{\circ }$