A New Algorithm for Multi-Area Power Flow

Abstract

In this paper, a new algorithm computing the multi-area power flow problem is presented. This algorithm is suitable for AC synchronous areas operating in steady-state conditions and interconnected by means of AC tie-lines. In particular, a new iterative composition/decomposition matrix procedure is adopted. For each area, the classical PV, PQ, and slack bus constraints are defined, allowing the computation of the power flow of each area independently. This independency of the power flow solution of each area allows exploiting the parallel computation technique. The overall power flow is then computed by putting together all the solutions of each area iteratively, by means of the tie-line (i.e., the lines interconnecting the areas) admittance matrix. The present multi-area method is novel and completely general and once the power flow solution of each area is separately achieved by any power flow solver (e.g., Newton-Raphson and derived, PFPD, or other), it makes suitable use of both a Thevenin’s theorem generalization and a novel tie-line admittance matrix. In this direction, the method is not a new power flow algorithm but a new multi-area algorithm, which starts from the solutions of the power flow of each area, each considered with its own slack-bus. Applications of the algorithm to standard test cases are presented. Eventually, to test the validity of the method, numerical comparisons with the commercial software DIgSILENT PowerFactory are performed.

Keywords

• AC/DC transmission networks
• distributed slack bus
• multi-area power flow
• multi-area power systems
• parallel computing