Rectifier Current and Inverter Extinction-Angle Control

Correct Answer

C — Statement-1 is False, but Statement-2 is True

Concept and Reasoning

Normal LCC-HVDC control coordinates the terminals so the rectifier commonly controls DC current through firing angle while the inverter maintains a minimum extinction angle γ. This provides current regulation while preserving commutation margin at the inverter. The correct statement combination is option C.

Calculation / Key Relation

Rectifier: constant-current control

inverter: constant-extinction-angle control (normal mode)

Exam Takeaway

LCC rule of thumb: rectifier controls current, inverter protects γ.

Common Mistake

Do not interchange firing-delay and extinction-angle roles between normal rectifier and inverter control.