Issue on Unbalanced Load Flow on Simscape Power System

Everytime that I try to calculate a tri phase load flow on a model that contains a synchronous machine, i get this error on Matlab Command Window: ‘Matrix close to singular or badly scaled’

However, the Balanced Load Flow works perfectly, for the same model.

Any idea how to solve this?

[Joel Van Sickel]

When you say tri phase load flow, do you mean load flow on an unbalanced system? Which load flow tool are you using and can you share your model?

[Augusto Janssen Harger da Silva]

Ops, sorry, I mistyped... Three phase load flow would be the correct expression. That means I am selecting the parameter "Connectors" to ABC instead of Single in Load Flow Bus Block.

I am using the load flow tool from the powergui block.

[Nachiappan]

Hello while performing unbalanced load flow in my network, I can't measure either real power or reactive power only voltage and angle can be measured. Can you guys help.

Answer 1

[Joel Van Sickel]

Hello Augusto,

the issue is likely with the model. It is possible that your model is 'stiff' making it hard to simulate. You could try adding snubber resistors to your motor.

This example can be modified to work with unbalanced load flow. https://www.mathworks.com/help/physmod/sps/examples/initializing-a-5-bus-network-with-the-load-flow-tool-of-powergui.html

Here is an file with the model above set up for unbalanced load flow working in 2020a. If you have an older verison you can modify the example to switch it to unbalanced and see it working with a synchronous machine.

Regards,

Joel

[Joel Van Sickel]

ignore that comment, change your angle values to this: [0 -120 120]

[Augusto Janssen Harger da Silva]

Thank you Joel, changing the angle values worked!