For the system of Fig. E7.8.1, assume bus 1 is the swing bus \left(\delta_1=0 \text { and }\left|\widetilde{V}_1\right|=1.0 \mathrm{pu}\right). Then we can make an initial guess for bus voltage vector \bar{x}^0=\left(\delta_2,\left|V_2\right|, \delta_3,\left|V_3\right|, \delta_4\right., \left.\left|\widetilde{V}_4\right|\right)^t=(0,1,0,1,0,1)^t. Note, the superscript 0 means initial guess. Compute the mismatch power vector for this initial condition.
40.0076 + 0-40.0076 + 80.016 = 0.1004.
The mismatch power vector is now
\begin{gathered} \Delta \bar{W}^0=(0.0978,0.374,-0.0056 \\ -0.00166,0.2527,0.1004)^t \end{gathered}