EFFICIENCY ANALYSIS OF POWER FLOW METHODS

• Grant number: 08/05190-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2008
• End date: June 30, 2009
• Field of knowledge: Engineering - Electrical Engineering - Power Systems
• Principal Investigator: Joao Bosco Augusto London Junior
• Grantee: Vanessa Nucci Pigatin
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 04/04672-4 - Power system analysis and control, AP.TEM

Abstract

Methods for power system analysis, such as energy restoration, planning, loss minimization, contingency analysis usually require power flow calculations, which are in general repeated several times for each analysis. This intensive use of power flows for large systems makes more relevant the development of faster and more reliable power flow methods. Traditional power flow methods, such as Newton-Raphson method and Fast Decoupled Power Flow Method (FDPFM), require the solution of a large set of non-linear equations to determine the complex voltages. This set of non-linear equations is solved using a process of linearization and iteration. At each iteration the non-linear system of equations is approximated by a linear matrix equation, and the solution of this linear system has computational complexity order O(n3), where n is the number of complex voltages to be calculated. Taking advantage of the radial nature of distribution systems, in 1988 SHIRMOHAMMADI et al proposed a more efficient power flow method, where the radial system is efficiently solved by the direct application of Kirchhoff's voltage and current laws. To radial system this method has a computational complexity order O(n) to each iteration. However, to apply this method for meshed system, it is necessary to use a procedure to break the interconnected system at certain points in order to convert it into one radial system. The computational complexity of this procedure depends on the number of system cycles. In this project a comparative study of the FDPFM and the power flow method proposed by SHIRMOHAMMADI et al is proposed. The main objective of this study is to evaluate the adequacy of the method proposed by SHIRMOHAMMADI et al to meshed transmission systems, in relation to the number of system cycles.