back word and forward power flow method is to be used for electrical distribution systems. 

in this system first voltage drop is to be calculated based on impedance and current injected at each load, equipment by back ward sweep. then by the forward sweep assume voltage profile at each node is 1.0 per unit then calculate voltage at each node check for convergence in the next steps. once it is converged stop the solution and print the results of voltage, voltage angle, active power loss and reactive power loss etc.

do you have any quarries while calculating currents of each load go through the text book. "modelling of distribution system by william kresting".

with regards

Ganesh

Dear Gani,

Thanks for your kindness and valuable time.

I have already applied Backward-Forward method on balance systems. I was wondering finding an example for unbalance systems.

Kind Regards,

Hossein.

dear sir 

you have to down load the data sheets of unbalanced electrical distribution system examples from ieee web site. they will proved data for 13 bus , 37 bus and 52 bus system. then you came to know that what are the currents you have to calculate and how to model the transformer for different connection types through singularity issue. 

kind regards

Ganesh

You have model all the transformers, line models and many line parameters separately. Kindly go through the papers of Prof(Dr.).D.Thukaram, IISc Bangalore who has first initiated this work   

Dear Sree hari charan Cherukuri,

Could you please send me the full name of the paper which have some numerical examples?

Regards,

Hossein.

Thukaram. D., Wijekoon Banda, H. M. and Jerome. J.

1999. A robust three phase power flow algorithm for

radial Distribution systems. Electric Power Systems

Research. 50(3): 227-236.

Kindly go through the above mentioned paper 

In addition to the Reference given by Sri Hari Charan Cherukuri, you may refer the Following Papers also.

1.   Efficient three-phase power-flow method for unbalanced radial distribution systems 

Mahmoud,K. , Abdel-Akher

This paper presents an efficient three-phase power flow algorithm for distribution network analysis. A new transformer model with various connections is implemented in the forward/backward sweep power flow method. The developed method provides an effective solution to the singularity problem of the nodal admittance submatrices appeared in some transformer configurations. Different load models and capacitor banks are also implemented with any number of phases and any connection. The proposed load flow has been tested using both the IEEE 4 and 34 node test feeders. The obtained results show that the proposed load flow is very efficient and the numerical solution is identical to that provided with the IEEE data.

Link:   http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5476323&abstractAccess=no&userType=inst

2.   Three-Phase Unbalanced Radial Distribution Load Flow Method

K.Krushna Murthy,  Dr. S.V. Jaya Ram Kumar

Abstract:

This paper deals with a new, efficient power flow method for unbalanced radial

distribution systems based on improved backward/forward sweep (BFS) algorithm.

This proposed method utilizes simple and flexible numbering scheme and takes full advantage of the radial structure of distribution systems.This method is tested

on an 8 - bus Three - phase unbalanced distribution system.

The numerical test proves this method is very robust and has excellent  convergence characteristics.

Key Words:

Backward/Forward Sweep, Radial DistributionSystems (RDS)

Link:   http://www.irjes.com/Papers/vol1-issue1/F11039042.pdf

P.S.

Dear Prof.  Subramanyam,

Thank you so much for your answer and help.

Regards,

Hossein.

Dear Mr. Syed Hossein I am one of new Matlab user . My Objective Function is to reduce the reactive power loss(refer to attachment ) .

I got a code for simple objective function val = (x - 15)^2 + (y - 20)^2 , I run this and observe the results  and now i am quite familiar with PSO working on matlab . But 

My objective is quite complex so please share program for reactive power loss minimization if any one have. Similar program will also help me in this regards 

Dear Arif,

I could not find the attachment. Could you please email it to me?

[email protected]

Kind Regards,

Hossein.

This paper presents a robust FBS method for unbalanced systems.