Existing starting algorithms for assessment of initial guess of variables to calculate steady states by Newton method were considered and studied. The presented results of computational experiments of application of starting algorithms on foreign and Russian power systems confirmed that though starting algorithms in some cases increase reliability of Newton method and decrease the number of iterations, any of the existing ones does not guarantee calculation of steady states by Newton method. The studies showed that Newton method is a reliable method for power flow calculation including ill-conditioned system only if initial guess of variables corresponds to parameters of stable steady state, otherwise the method diverges. It is revealed that existing starting algorithms do not guarantee obtaining of such initial guess of variables. Authors propose to use a solution of linear nodal admittance matrix equation without load or with load converted to current or shunt admittance as starting algorithms for obtaining initial guess of variables. Computational experiments showed that the proposed starting algorithms allowed calculating steady states by Newton method of the all tested systems, also how to decrease the number of iterations.