It is possible that the issue you are experiencing with your 24-pulse diode rectifier could be caused by a problem with the waveform, the leakage inductance, or the angle of the transformer. Here are some potential issues that you may want to consider:
Waveform: Make sure that the waveform of the 24-pulse diode rectifier is correct. This could be done by comparing the simulated waveform to a measured waveform or to a theoretical waveform.
Leakage inductance: The leakage inductance of the transformer can affect the performance of the rectifier. Make sure that the leakage inductance is within the specified range.
Angle of the transformer: The angle of the transformer can also affect the performance of the rectifier. Make sure that the angle is set correctly.
If none of these issues seems to be the cause of the problem, you may want to try simulating the rectifier in a different software or with a different simulation model to see if the issue persists. This will help you determine if the issue is with the simulation or with the actual rectifier.