The one line diagram of a four bus power system is as shown in figure. Reactance’s are given in per unit on a common MVA base. Transformers T1 and T2 have tap setting of 0.8 ∶ 1, and 1.25 ∶ 1 respectively. The bus admittance matrix is
1
\(\left[ {\begin{array}{*{20}{c}} { - j125}&0&{j100}&0\\ 0&{ - j6.25}&0&{j5}\\ {j100}&0&{ - j89}&{j9}\\ 0&{j5}&{j9}&{ - j13} \end{array}} \right]\)
2
\(\left[ {\begin{array}{*{20}{c}} { - j100}&0&{j100}&0\\ 0&{ - j5}&0&{j5}\\ {j100}&0&{ - j109}&{j9}\\ 0&{j5}&{j8}&{ - j13} \end{array}} \right]\)
3
\(\left[ {\begin{array}{*{20}{c}} { - j100}&0&{j100}&0\\ 0&{ - j6.25}&0&{j5}\\ {j100}&0&{ - j89}&{j9}\\ 0&{j5}&{j9}&{ - j14} \end{array}} \right]\)
4
\(\left[ {\begin{array}{*{20}{c}} { - j125}&0&{j100}&0\\ 0&{ - j6.25}&0&{j5}\\ {j100}&0&{ - j109}&{j9}\\ 0&{j5}&{j9}&{ - j13} \end{array}} \right]\)