Approximation Formulae for Dependent Load Flow Variables

Approximating formulae are derived relating an arbitrary load flow variable, y, to the independent injections of a general load flow problem Ζ. The relations are either linear, or quadratic, y = ßΖy = ßΖ + Ζ. TCΖ. . Both the vector ßand the matrix C can be explicitly determined. The linear expansion has the properties of a general DC-load flow with the consequent applications in security and economy dispatch. The quadratic expansions, in addition, yield very accurate transmission loss formulae. A Numerical analysis is performed on the approximation errors