Adaptability Analysis of Commutation Failure Prevention Control in HVDC Systems under Interphase Short-Circuit Faults

With the rapid development of China's hybrid AC-DC power grid, commutation failure in line-commutated converter-based high-voltage direct current (LCC-HVDC) transmission systems has become one of the critical factors severely threatening the safe and stable operation of the grid. The commutation failure prevention (CFPREV) module, commonly employed in practical engineering, is an effective measure to prevent commutation failures. However, under interphase short-circuit faults, the fault detection indicators of CFPREV may fail to accurately reflect the actual severity of the fault, thereby affecting its effectiveness in suppressing commutation failures. This paper quantitatively investigates the adaptability of CFPREV under interphase short-circuit faults, analyzes a real-world case demonstrating CFPREV failure under such conditions, and finally provides recommendations for improving CFPREV performance.