I put a breaker model in my circuit. And i found that it closes when the current is zero and the external signal is 0.

The circuit is a systhetic circuit usually used for circuit breaker. I add a half sine current on the breaker, and then put a very high voltage Oscillating voltage on it. The half sine current (20kA) meets zero at the 0.01s, and the extern signal for breaker is 0.009s, which means that it will open at the 0.01s. And it actually did. The Oscillating volatge source is added at 0.011s. However, when I reduce the half sine current to about 5kA, something magical happened. The breaker closes again and there is another current that flows through the breaker. And this problem still existed even when I changed the time stamp to put a very high voltage Oscillating voltage to 0.015s as I thought it needed enough time to open the breaker.

I really want to know why this happens and how to solve the problem that the breaker doesn't opens as i think.

Here is the current that flows through breaker.

Here is my breaker configurations.

[添茂 吕]

Oh, I just found that when the Oscillating voltage is very high for example 200kV, the breaker will be broken. Is there a Withstand voltage value in the breaker module?

[Ashok]

Could you please share your Simulink files to replicate the issue?

Answer 1

[Joel Van Sickel]

The model is not implementing a voltage breakdown. The issue is most likely with the input signal that you are using, or the solver settings. In general, this breaker works as you have seen, and it will operate at zero crossings when opening, but can close at any time. You can see the model for the breaker in part by "looking under mask" with the right click option on the block. It is likely that if you are using very high voltages, but also simulating very small signals (such as when the breaker is off) that you need to increase the tolerance of your solver settings. Try 1e-4 or 1e-5 for the relative and absolute tolerances in the solver settings and see if that clears things up. (this won't do anything if you are using a discrete time simulation, in which case your time stpe might be too large). We can't provide more guidance without your model.