The optimal reactive power flow model in mixed polar form based on transformer dummy nodes

Abstract

This paper proposes a simple optimal reactive power flow (ORPF) model in mixed polar form based on the dummy nodes transformer model. By introducing voltage magnitude variables at the dummy nodes to express the transformation relationships of the power and the voltages of ideal transformers, the proposed model does not need to consider the variables of transformer ratios directly. So the power equations of the transformer branches do not contain complex items multiplied by the squares of variables, but drop from four‐dimensional variables of the transformer equivalent ∏ circuits to three‐dimensional variables. It simplifies the ORPF model efficiently and solves the problem of the traditional model which is a little complicated and hard to calculate. The calculation results of IEEE‐30, ‐57, ‐118, and ‐300 bus systems show that the proposed model converges quickly and the number of iterations reduce by more than half compared to the traditional model. With higher computational efficiency and more stable numerical property, the proposed model is suitable for practical application in large‐scale power systems. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.