How to simulate an inverter commutation failure in a two-terminal dc link?

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I have a two-terminal dc link in my network with a CDC4T model. I have referred to PAGV2 and it reads, "To simulate an inverter commutation failure, bypass the inverter and apply an ac system shunt at the inverter with a reactance equaling the leakage reactance of the converter transformer".

Normally, when commutation failure occurs, the direct current increases instantly and the extinction angle (gamma) decreases below gamma minimum. I tried the approach dictated by PAGV2 but the results do not fit in the commutation failure scenario. In my case, the reverse is happening, i.e., direct current decreases and gamma increases.

I would really appreciate any help.