Question 7.8: Given a generator and a system with reactances of Xs = 1.2 a......

The given parameters inserted in the static-stability limit curve equation
[Eq. (7.53)] yield

P^{2}+\left[Q-\frac{V_{t}^{2}}{2}\left(\frac{1}{X_{e}}-\frac{1}{X_{s}}\right)\right]^{2}=\left[\frac{V_{t}^{2}}{2}\left(\frac{1}{X_{s}}+\frac{1}{X_{e}}\right)\right]^{2}      (7.53)

For P = 0, we have by simple substitution:

Similarly, we get

For P = 0.25:      Q = -0.740.
For P = 0.5:        Q = -0.704.
For P = 0.75:      Q = -0.643.
For P = 1.00:      Q= -0.555.