Graphs are paused during simulation in Simulink and do not resume once RLC load is added via circuit breaker

Hello everybody,

I have created a grid-connected PV system in Simulink. It consists of an inverter (with universal bridge), a controller, a medium voltage transformer and a high voltage transformer with grid utility connection. I also need to add a fixed coil reactive power compensator (in 8 steps from 2 Mvar to 16 Mvar) in MV side to compensate the feeder capacitance (it is considered as RLC load of -15 Mvar between the high voltage transformer and the grid operator). These loads are all connected in parallel.

I need to change the coil levels via a three-phase circuit breaker depending on the total reactive power via controller. The problem is that when I change the level of the compensator to decrease or increase the reactive power, all the graphs related to the value measurement are stopped during the simulation while I get no errors.

Does anyone know what the problem is?

Thanks in advance

Answer 1

[Joel Van Sickel]

It sounds like the simulation is "hanging" aka, it starts taking such small time steps that nothing appears to be happening. This would not throw an error and would make your plots look they are not getting more data. Does this seem like a possibility. If that is the case, it is normal for switcing in loads like this in specialized power systems as it can cause a need for very small time constants. The easiest fix for that is to do a fixed step simulation. An alternative would be to switch from specialized power systems to simscape, which won't have the same problem when changing loads. However, if you can share your model here, I can take a closer look at it try and be more specific.