Hi Felix
According to my understanding, It seems that the error message is expected. Touse this model for load flow analysis, you have to change the bus type to "PQ."
In the model "power_simplealt", the machine is connected with the voltage source in series directly and there is no other component (e.g.,resistor and/or inductor) between them. So there is only one bus which is the interconnection between the machine and the voltage source.
In load flow analysis, it is not allowed to define a bus as both swing bus and PV bus. By changing the bus type of the machine to be 'PQ' busand specifying reasonable active and reactive power generation in the 'Load Flow' tab, the load flow analysis will work.
When using Machine Initialization, the restriction above does not apply, which is why you are able to compute. But strictly speaking, when using the machine initialization, the bus type in the App should be selected as 'P & Q generator', not 'P & V generator'.
Generally, for a simple circuit, using either load flow analysis or machine initialization is applicable. However, for a complicated circuit (e.g.the shipped example model 'power_LFnetwork_5bus' ), the load flow analysis should be used.
I hope it helps.
