Machine initialization in the powergui is not working with a three-phase circuit breaker in the model with a synchronous generator and the infinite bus

Good day.

I am trying to design a model where a synchronous generator is connected to the infinite bus. In this case I want to check my synchronization subsystem, so I want to simulate the operation of the generator when it starts from the rest, and when all synchronization requirements are fulfilled, close the main circuit breaker and connect the generator to the power grid (infinite bus). However, right now I want to be sure that the connection of the synchronous machine to the grid is working properly and I experienced a problem with the machine initialization mode.

I am using this mode in order to specify active power (SG in a P&V generator mode), hence the initial conditions, and so on. It perfectly works when the generator is connected to the infinite bus (programmable three-phase voltage source, swing mode), and there is no circuit breaker in the system. As soon as I put the breaker between the generator and the grid, and trying to initialize the same process, I get the notification "Unable to find machine initial conditions for the parameters you specified in the Machine Initialization tool", and that I have to use the Load Flow instead, which doesn't help in order to change the initial conditions. On top of that in the machine initialization window I see that terminal voltage is around 10^5 pu, so as you can imagine it interferes the whole system in terms of the torque, speed, currents and etc.

Are there any options to properly specify the initial conditions of the system, or maybe there are other options how to simulate the transient process of connection of the generator to the infinite bus. Thank you in advance.

Answer 1

[Jinzhao Hu]

Hi Sturov:

I currently have the same problem with you, have you fix it?

[Efim Sturov]

Hi there,

If I am not mistaken (since it's been a while ago), you can initialise a system when it is connected to the grid (without a circuit breaker). Write down all the calculated parameters and then introduce a breaker. Just in case now you can re-write the system’s parameters.

The main issues here as far as I remember is a proper choice of a solver. In my case (hydraulic plus electrical domain) – only 023tb worked out well, but I was also working around with the tolerance boundaries. Unfortunately can’t tell you more, at least now, since I’ve finished the model and after that did not touch it at all. Hopefully, I've managed to help you even a little bit.