Minimum spanning tree of an IEEE bus network

hi Guys.

I have a 9 bus IEEE test feeder in Simulink and I would like to get a minimum spanning tree from one node to the other. the problem is I am struggling to automatical represent the physical network in matlab so I can peform minimum spanning tree.

how do I represent a physical network by its edges and nodes in matlab from simulink.

thanks

[darova]

Can you please attach data or image?

[sibabalo noludwwe]

at the moment I am using the attached network just to get the concept of converting a simulink system into a graph object.

Answer 1

[Hari Krishna Ravuri]

Hi,

I understand that you have a 9 bus IEEE test feeder model in Simulink and wanted to get a Minimum Spanning Tree for the network. As of now, there is no in-built function in MATLAB or Simulink to convert a Simulink model into a Graph. But you can write a script to perform this. For this you need to decide what blocks in the Simulink model will be interpreted as Nodes and what blocks / connections will be interpreted as edges in the graph.

You can use the get_param property to get to the Outport and you can start traversing the whole network. When you traverse a block update the Graph depending on the way you want to interpret the block either as a node or as an edge. If the network is complex, you may traverse the same graph more than once. In this case, I suggest you perform a Depth First Traversal. Please refer https://www.mathworks.com/help/simulink/slref/block-specific-parameters.html for Block specific parameters. Once the graph is ready, if the graph is dense, I suggest using Prims Minimum spanning tree algorithm. If the graph is sparse, I suggest using Kruskal's Minimum spanning tree algorithm.

[sibabalo noludwwe]

thank you,

I tried something like this and I also got the distribution lines themselves represented as nodes and also struggled to convert the three lines as one edge and I was not able to load their weight as well. please assist further.

thanks

[Hari Krishna Ravuri]

Having three lines between two blocks can be viewed as multigraph. You can convert three lines as one edge by converting the multigraph into a single graph. Please refer https://www.mathworks.com/help/matlab/ref/graph.simplify.html for more information. By using get_param you can get the line parameters and calculate the cost.

Answer 2

[sibabalo noludwwe]

THANKS,

when i use simplify I am getting this error:

Undefined function 'simplify' for input arguments of type 'matlab.graphics.chart.primitive.GraphPlot'.

attached is the graph that i want to simplify and instead am getting all the blocks in simulink.

[Hari Krishna Ravuri]

The simplify function takes the Graph object as Input. Please refer https://www.mathworks.com/help/matlab/ref/graph.simplify.html#mw_69007ace-39e1-4301-84d6-d832f76a95ee_sep_shared-G

Answer 3

[sibabalo noludwwe]

I did exactly as the examples on the referal but it does not seem to work with a directed graph I am not sure what is the problem.

Also I used the following

b=find_system('power_13NodeTestFeeder','SearchDepth',1,'Type','block');

h=get_param(b, 'Handle')

and am getting parameters of all the blocks. how do I make sure I only get load flow buses.