Optimal power flow by a nonlinear complementarity method

A nonlinear complementarity method for solving nonlinear optimal power flow problems is presented. This method stems from proposed reformulation of complementarity problems as nonlinear systems of equations which age, in turn, solved by a Newton-type method. To reformulate optimal power flow problems as nonlinear systems of equations we employ a function /spl psi//sub /spl mu//: /spl Rscr//sup 2//spl rarr//spl Rscr/ that satisfies the property /spl psi//sub /spl mu//(a,b)=0/spl hArr/a>0, b>0 and ab=/spl mu/, for any /spl mu/>0. Then, unlike interior-point methods, the new method handles the complementarity conditions for optimality, s/sub i//spl ges/0, /spl pi//sub i///spl ges/0 and s/sub i//spl pi//sub i/=0, without requiring that s/sub i/>0 and /spl pi//sub i/>0 be satisfied at every iterate. Numerical results illustrate the viability of the proposed method as applied to several power networks. A comparison with two interior-point algorithms is discussed.