Unit Commitment

  • 21 July 2021
  • 2 replies


Hello everyone,

I am new to AIMMS, I am trying to solve a unit commitment problem with four thermal generator units and a PV unit. I have added the four generators in a set  with index (u) with all their parameters in the model. Now, I want to add another source of power supply which is PV as a fixed parameter, that is, constant power output. How do I add and index the PV  as it’s also a generating unit but with different characteristics? This would also affect my power balance constraints of sum of total power supply equal to load demand. 


Best answer by mohansx 21 July 2021, 23:58

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One way of doing this is to have a root set of generators and have one subset for thermal units and another for PV unit(s). This approach will be beneficial if you need to add multiple PV units or constraints specific to them in the future. 


Set Generators

Index: u

Definition: Thermal + PV


Set Thermal

Index: t

Subset of: Generators


Set PV

Index: p

Subset of: Generators


Use index u in constraints which should include all the different power sources (for example, total power supply). Use index t in constraints which are relevant only for thermal units (for ramp up/ramp down constraints) and similarly, use index p for any constraints specific to only PV units. 



Thank you @mohansx . This was quite helpful.


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