Digital Calculation of 3-Phase Short Circuits by Matrix Method

The literature describing methods of analysis suitable for use with electronic digital computers in the power-system load-flow problem has grown until the papers can now be numbered in hundreds. This paper presents a classification that can be applied to all methods, with theory and discussion of the important problems of acceleration of the solution, criteria for convergence and of the inherent difficulties that enable only general comparisons to be made between methods. An extensive bibliography lists the more significant papers on the subject.

Numerical techniques in solution of power-system load-flow problems

An algorithm has been developed to form the bus admittance matrix Ybu,, by forming the network through a step-by- step addition of a line or a passive element to the system, taking into account the mutual coupling between the elements. Two sets of formulas have been derived for the addition of a tree branch and for the addition of a link. This method eliminates the formation of incidence matrices and does not require singular or nonsingular transformations. This algorithm is very convenient for calculation in digital computers.

Step-by-Step Formation of Bus Admittance Matrix

The open-path-closed-path (mixed junction pair and mesh) relations derived in Part I1 are related by invariant transformations and their inverses to the open-path (junction pair) relations with reference ground and reference different from ground. Invariant transformations are also derived for transforming from one set of open-path-closed-path relations to any other set of open-path-closed-path relations. It is also demonstrated that the methods of Part I are applicable to general networks, with impedances and/or simple and complex autotransformers to ground. The immediate major application of the open-path-closed-path reference frame is in the area of total losses and incremental losses.

H. W. Hale

Papers

Digital Computation of Driving Point and Transfer Impedances