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Fast computation and stable convergence technique for unbalanced load flow calculation in large‐scale systems
Author(s) -
Shirasaki Keisuke,
Uchida Naoyuki
Publication year - 2010
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.21034
Subject(s) - jacobian matrix and determinant , symmetrical components , computation , transformer , electric power transmission , convergence (economics) , control theory (sociology) , newton's method , three phase , voltage , computer science , electric power system , transmission line , transmission system , algorithm , mathematics , topology (electrical circuits) , transmission (telecommunications) , engineering , power (physics) , physics , electrical engineering , economic growth , telecommunications , control (management) , quantum mechanics , artificial intelligence , nonlinear system , economics , combinatorics
This paper presents a new method of unbalanced load flow calculation to improve complexity by the method of advanced symmetrical coordinates. Usually, the electric power system has been calculated only by the positive phase sequence component on the assumption that three‐phase transmission lines and loads are balanced. However, many ultrahigh‐voltage transmission lines are not transposed, and therefore mutual inductances cause negative sequence currents in the trunk transmission system. Negative sequence currents cause heating of generators and transformers, and therefore the three‐phase sequence component should be calculated accurately. We examined the fast computation and good convergence performance of unbalanced load flow calculation by models of three‐phase transmission lines, transformers, and loads. The proposed method is not the phase coordinate system but the method of symmetrical coordinates. This technique decreases numerical complexity by the use of a simplified Jacobian matrix. The convergence performance of this method is inferior to that of the usual Newton–Raphson method. As a consequence, the problem of poor convergence performance is alleviated by a technique for the newly developed deceleration Newton method. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(1): 17–24, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21034