Single phase load flow usecase

I am building a single phase network in Simulink which has an ac source, and couple of cascaded rl load blocks with rl transmission lines. Simulink threw an error when I connect the load flow bus blocks to this model and when I compute load flow from powergui. However an equivalent three phase network was working fine with load flow. Now I have a question if matlab can compute loadflow of single phase system and in what circumstances is a single phase load flow made.

Simulink single phase loadflow model

Error message:

[Ioannis Iliopoulos]

I have the exact same problem. Did you find any solution?

Answer 1

[Garmit Pant]

Hello Jagadeesh,

Load flow analysis using the “powergui” block in Simscape is more suited for three-phase electrical circuits. However, single-phase unbalanced load flow can also be performed.

To perform an unbalanced load flow, you must define all the “Load Flow Bus” blocks in your model with the ‘Connectors’ parameter set to one of the following values: ABC, AB, AC, BC, A, B, or C. For an unbalanced load flow, the relevant load flow blocks are:

• AC Voltage Source
• Asynchronous Machine
• Parallel RLC Load
• Series RLC Load
• Synchronous Machine
• Three-Phase Dynamic Load
• Three-Phase Parallel RLC Load
• Three-Phase Series RLC Load
• Three-Phase Source

The “powergui” Load Flow tool will report an error if a model contains a mix of "Load Flow Bus" blocks set to perform a positive-sequence load flow and "Load Flow Bus" blocks set to perform an unbalanced load flow.

In the circuit you have designed, the “Load Flow Bus” block’s ‘Connectors’ parameter is still set to ‘single’. Since the parameter ‘Connectors’ is ‘single’, it prompts a balanced three-phase load flow. However, if the bus block is connected to an unbalanced load flow block, this will cause an error.

For further understanding, kindly refer to the following MathWorks Documentation:

• Refer to the ‘Parameters’ section of the “Load Flow Bus” block documentation: Load Flow Bus Documentation
• Refer to the ‘Parameters’ section to understand how to correctly set up a “powergui”: Powergui Documentation

I hope you find the above explanation and suggestions useful!