The utility model discloses a special high voltage direct current three strings of some strain insulator -strings of quintuplet for circuit, the strain insulator -string concatenates into insulator chain by dish -type suspension insulator, five tube -shapes of insulator chain are arranged, insulator chain edge two is listed as one end and is connected with the right angle link plate respectively, the right angle link plate is connected with a string gold utensil, insulator chain middle one is listed as one end and is connected with a string some gold utensil, the other end that insulator chain was connected with the right angle link plate is connected with socket -clevis eye, two among the socket -clevis eye are connected with one two a change yoke plate, make two change yoke plates of four socket -clevis eye connections, insulator chain middle one is listed as the other end and is connected with the PD link plate, two two become two yoke plates of a yoke plate and PD link plate and three changes and are connected, three become two yoke plates is connected through two link plates and two changes six yoke plates, two become six yoke plates is connected with strain clamp, strain clamp is connected with the wire, can effectual improvement strain insulator -string structural strength.