A1: There are a number of possible causes:
1. You did not turn on the option to simulate converter-interfaces resources, or the option to simulate type-3 wind plants. Execute the Faults | Options command and take a look.
2. The voltage at the plant’s terminal wander outside of the plant’s voltage limits. You can check the prefault voltage by simulating a 3-phase fault near the plant with fault impedance set to 9999+j9999 ohms and compare the voltage shown on the one-line against the plant’s max and min voltage limits. If this problem happens during the fault solution, there will see a message about “abnormal voltage” in the TTY window and it will tell you the voltage is too high or too low.
3. The fault is too close to the plant. As a result, the voltage at the terminal of the plant is below the low-voltage shut down.
4. Before the fault is applied, the plant is in an island that has no conventional generators. This error message can be found in the TTY window.