| 摘要 |
PURPOSE:To enable reliable protection of SCR by deciding SCRH converter where the fault current is supplied then dividing the current within allowable surge withstandability of SCR. CONSTITUTION:The current flowing to SCR converter 15 or 16 is detected by current detector 24 which provides detection signal to current decision 25, thereby upon occurrence of commutation failure of converter the decision circuit 25 detects the magnitude and the polarity of fault current thus to decide which one of converters 15, 16 has commutated thus to supply gate control signal through firing signal circuits 27 or 28 to all SCR of commutation failed SCR converters 15, 16 and to divide the fault current due to commutation failure to each SCR of SCR converters 15, 16. Since the fault current can be divided within allowable surge current of SCR, highly reliable protection is achieved. |
