International Journal of Applied Power Engineering (IJAPE) Vol. 13, No. 2, June 2024, pp. 351~361 ISSN: 2252-8792, DOI: 10.11591/ijape.v13.i2.pp351-361  351 Journal homepage: http://ijape.iaescore.com Three-phase model of SCIG-based variable speed wind turbine for unbalanced DSLF analysis Ismail Yusuf, Rudy Gianto Department of Electrical Engineering, Tanjungpura University, Pontianak, Indonesia Article Info ABSTRACT Article history: Received Aug 21, 2023 Revised Sep 6, 2023 Accepted Sep 28, 2023 Steady state performances of the electric power distribution system are normally assessed or evaluated based on load flow analysis. To properly carry out the analysis, a valid steady state load flow model of each distribution system component, including the wind power plant (WPP), needs to be developed. The present paper proposes a method for modeling and integrating squirrel cage induction generator (SCIG)-based variable speed WPP into a three-phase unbalanced distribution system load flow (DSLF) analysis. The proposed method is based on a single-phase T-circuit model of fixed speed WPP, which has successfully been applied to balanced electric power systems. In the present work, the single-phase T-circuit model is extended and modified to be used in steady state load flow analysis of three-phase unbalanced distribution systems embedded with SCIG-based variable speed WPP. Results of the case studies confirm the validity of the proposed method. Keywords: Load flow SCIG Unbalanced distribution system Variable speed Wind turbine generator This is an open access article under the CC BY-SA license. Corresponding Author: Rudy Gianto Department of Electrical Engineering, Tanjungpura University St. Prof. Dr. H. Hadari Nawawi, Pontianak 78124, Indonesia Email: rudy.gianto@ee.untan.ac.id 1. INTRODUCTION Load or power flow analysis is probably the most fundamental analysis in electric power system studies. Based on the analysis, the steady state performance of the electric power system can be assessed or evaluated. It has been acknowledged that a valid steady state model of each power system component needs to be derived and developed to enable the analysis to correctly be carried out. In the context of wind power plant (WPP) steady state load flow modeling, many methods have been proposed and developed in the last few years. Some of the methods are focused on fixed or near constant speed WPP modeling, and some deal with variable speed WPP modeling. Several techniques to incorporate fixed speed WPP have been introduced in some publications. The WPP steady state models in [1]–[3] are derived based on the equivalent circuit of the WPP induction generator. Three-node model of an asynchronous generator for load flow analysis has been proposed. The three-node model transforms the asynchronous generator equivalent circuit to several buses and branches [1]–[3]. A standard load flow program is then employed to obtain the load flow solution. A PQ model for an induction generator to be used in steady state load flow analysis has been developed [4]–[6]. The mathematical model in [4]–[6] is derived based on a formula that calculates the active and reactive powers of the induction generator. In the calculation of the powers, the turbine's mechanical power is assumed to be known. Various fixed speed WPP models for steady state load flow analysis have been introduced in [7], [8]. The WPP is modeled under unbalanced system conditions [8]. The developed model in [7] has the power formulations in terms of induction machine parameters, system terminal voltages, and mechanical input power. A method to integrate WPP into