Development of Three-Phase Unbalanced Power Flow Using PV and PQ Models for Distributed Generation and Study of the Impact of DG Models

With the increased installations of distributed generators (DGs) within power systems, load flow analysis of distribution systems needs special models and algorithms to handle multiple sources. In this paper, the development of an unbalanced three-phase load flow algorithm that can handle multiple sources is described. This software is capable of switching the DG mode of operation from constant voltage to constant power factor. The algorithm to achieve this in the presence of multiple DGs is proposed. Shipboard power systems (SPS) have other special characteristics apart from multiple sources, which make the load flow difficult to converge. The developed software is verified for a distribution system without DG using the Radial Distribution Analysis Package (RDAP). The developed software analyzes an IEEE test case and an icebreaker ship system. System studies for the IEEE 37-node feeder without the regulator show the effect of different models and varying DG penetration related to the increase in loading. System losses and voltage deviations are compared.

[1]  R.C. Dugan,et al.  Induction machine test case for the 34-bus test feeder -description , 2006, 2006 IEEE Power Engineering Society General Meeting.

[2]  J.R. Marti,et al.  A generalised three-phase power flow method for the initialisation of EMTP simulations , 1998, POWERCON '98. 1998 International Conference on Power System Technology. Proceedings (Cat. No.98EX151).

[3]  J. Teng.  A direct approach for distribution system load flow solutions , 2003 .

[4]  Fred Denny,et al.  Distribution System Modeling and Analysis , 2001 .

[5]  D. Shirmohammadi,et al.  A three-phase power flow method for real-time distribution system analysis , 1995 .

[6]  Tsai-Hsiang Chen,et al.  Distribution system power flow analysis-a rigid approach , 1991 .

[7]  W. H. Kersting,et al.  Radial distribution test feeders , 1991, 2001 IEEE Power Engineering Society Winter Meeting. Conference Proceedings (Cat. No.01CH37194).

[8]  K.L. Butler-Purry,et al.  A three phase load flow algorithm for shipboard power systems (SPS) , 2003, 2003 IEEE PES Transmission and Distribution Conference and Exposition (IEEE Cat. No.03CH37495).

[9]  Thomas Baldwin,et al.  Distribution load flow methods for shipboard power systems , 2003 .

[10]  S. Elangovan,et al.  Power Flow Analysis for Balanced and Unbalanced Radial Distribution Systems , 1999 .

[11]  J. Teng,et al.  Three-phase unbalanced distribution power flow solutions with minimum data preparation , 1999 .

[12]  N. Schulz,et al.  Unbalanced Distribution Power Flow with Distributed Generation , 2006, 2005/2006 IEEE/PES Transmission and Distribution Conference and Exhibition.

[13]  T. Baldwin,et al.  Distribution load flow methods for shipboard power systems , 2004, IEEE Transactions on Industry Applications.

[14]  Hsiao-Dong Chiang,et al.  Fast decoupled power flow for unbalanced radial distribution systems , 1995 .

[15]  J.-H. Teng,et al.  A Network-Topology-Based Three-Phase Load Flow for Distribution System , 2000 .

[16]  M. Laughton.  Analysis of unbalanced polyphase networks by the method of phase co-ordinates. Part 1: System representation in phase frame of reference , 1968 .