A Modified Backward/Forward Sweep Load Flow Method for Islanded Radial Microgrids

In this paper, a modified backward/forward sweep (BFS) load flow algorithm is proposed to solve power flow for islanded droop-controlled ac microgrids. The proposed method has been formulated such that the system frequency is one of the system’s unknown variables which is typical for an islanded network justifying further the absence of a slack bus. As a result, new equations have been systematically developed and incorporated with the conventional BFS method. The modified BFS method has been applied to the 33-bus test system and the results obtained are compared with simulation results from the direct BFS method as well as PSCAD/EMTDC. In comparison to the conventional methods, the proposed method is accurate, simple, and easy to implement thus serving as a useful tool for microgrid analysis and planning.

[1]  T.C. Green,et al.  Modeling, Analysis and Testing of Autonomous Operation of an Inverter-Based Microgrid , 2007, IEEE Transactions on Power Electronics.

[2]  Ariovaldo V. Garcia,et al.  Three-phase fast decoupled power flow for distribution networks , 1996 .

[3]  U. Eminoglu,et al.  A new power flow method for radial distribution systems including voltage dependent load models , 2005 .

[4]  H. L. Nguyen,et al.  Newton-Raphson method in complex form [power system load flow analysis] , 1997 .

[5]  Babu Narayanan,et al.  POWER SYSTEM STABILITY AND CONTROL , 2015 .

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

[7]  Douglas A. G. Vieira,et al.  A fast power flow method for radial networks with linear storage and no matrix inversions , 2014 .

[8]  S. M. Moghaddas-Tafreshi,et al.  Distributed generation modeling for power flow studies and a three-phase unbalanced power flow solution for radial distribution systems considering distributed generation , 2009 .

[9]  Fan Zhang,et al.  A modified Newton method for radial distribution system power flow analysis , 1997 .

[10]  M. H. Syed,et al.  A Novel Approach to Solve Power Flow for Islanded Microgrids Using Modified Newton Raphson With Droop Control of DG , 2016, IEEE Transactions on Sustainable Energy.

[11]  José Coto,et al.  Direct Backward/Forward Sweep Algorithm for Solving Load Power Flows in AC Droop-Regulated Microgrids , 2016, IEEE Transactions on Smart Grid.

[12]  Ehab F. El-Saadany,et al.  A Novel and Generalized Three-Phase Power Flow Algorithm for Islanded Microgrids Using a Newton Trust Region Method , 2013, IEEE Transactions on Power Systems.

[13]  Shou-Yung Chu,et al.  An efficient power flow algorithm for weakly meshed distribution systems , 2012 .

[14]  Mariano Giuseppe Ippolito,et al.  Backward solution of PV nodes in radial distribution networks , 2009 .

[15]  E.F. El-Saadany,et al.  Adaptive Decentralized Droop Controller to Preserve Power Sharing Stability of Paralleled Inverters in Distributed Generation Microgrids , 2008, IEEE Transactions on Power Electronics.

[16]  Adam Semlyen,et al.  Efficient load flow for large weakly meshed networks , 1990 .

[17]  Xiao-Ping Zhang,et al.  Fast three phase load flow methods , 1996 .

[18]  Tsai-Hsiang Chen,et al.  Loop frame of reference based three-phase power flow for unbalanced radial distribution systems , 2010 .

[19]  Reza Iravani,et al.  Unbalanced Model and Power-Flow Analysis of Microgrids and Active Distribution Systems , 2010, IEEE Transactions on Power Delivery.

[20]  M. H. Syed,et al.  A simple and accurate approach to solve the power flow for balanced islanded microgrids , 2015, 2015 IEEE 15th International Conference on Environment and Electrical Engineering (EEEIC).

[21]  Esmaeel Rokrok,et al.  Adaptive voltage droop scheme for voltage source converters in an islanded multibus microgrid , 2010 .

[22]  Felix F. Wu,et al.  Network Reconfiguration in Distribution Systems for Loss Reduction and Load Balancing , 1989, IEEE Power Engineering Review.

[23]  K.. De Brabandere,et al.  A Voltage and Frequency Droop Control Method for Parallel Inverters , 2007, IEEE Transactions on Power Electronics.

[24]  Josep M. Guerrero,et al.  Design and Analysis of the Droop Control Method for Parallel Inverters Considering the Impact of the Complex Impedance on the Power Sharing , 2011, IEEE Transactions on Industrial Electronics.

[25]  A.H. El-Abiad,et al.  Three phase load flow program , 1976, IEEE Transactions on Power Apparatus and Systems.

[26]  Guzmán Díaz,et al.  Operating point of islanded microgrids consisting of conventional doubly fed induction generators and distributed supporting units , 2012 .

[27]  C. W. Taylor,et al.  Load representation for dynamic performance analysis , 1993 .

[28]  Wenchuan Wu,et al.  A three-phase power flow algorithm for distribution system power flow based on loop-analysis method , 2008 .

[29]  D. Shirmohammadi,et al.  A compensation-based power flow method for weakly meshed distribution and transmission networks , 1988 .

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