The main mechanism that we have for flagging components going outside of a certain operating limit is by using the passive components from Simscape Electrical (resistor, capacitor and inductor), where you have an Operating Limits tab that allows you to throw warnings or errors if the component goes outside of your prescribed limits.
In your test model, the voltage sensor provides an open circuit, so no current flows through the diode anyway. If you had a complete circuit with the voltage sensor connected across an exponential diode, you would see convergence issues due to the exponential term getting large. For a model involving a sufficiently high series resistance (such as in the piecewise linear Foundation resistor), the model is basically a two-state resistor that can handle any voltage across it.
