The thesis is a new approach to the large electric power systems static stability evaluation. The characteristic polynomial obtained is of high order as a rule. Application of algebraic criterion in such cases requires cumbersome arithmetic or large size determinants calculation. This work presents analytical study of the conditions under which roots of the characteristic polynomial in the right half of the complex field appear. For this purpose preliminary transformation of the polynomial is proposed, which leads to clear results and conclusion for any ratios of polynomial coefficients when static stability is being lost. Designed questions can serve to create new necessary conditions for large power systems stability (High Order Characteristic Polynomial Roots’ Location Analysis).