Special HVDC thyristor change of current backward recovery phase protection circuit for the valve

The utility model provides a special HVDC thyristor recovery protection firing circuit for the valve, including positive voltage sampling circuit, burden voltage sampling circuit, RS flip-Flop, signal extension circuit and amplifier circuit, gathering thyristor both ends voltage through positive voltage sampling circuit and burden voltage sampling circuit, when thyristor both ends voltage exceedes the one definite value, can producing one voltage signal, thyristor both ends voltage build-up rate has exceeded the scope that endures of self in time backward recovery phase, and the protection circuit can send trigger impulse at once and triggered the thyristor this moment, and protection thyristor will not is avoided the thyristor to hinder the voltage damage for some reason by the trouble voltage breakdown.