The invention proposes a series compensator and control method. The series compensator includes a series transformer, series transformer bypass equipment, a voltage source converter, converter rapid bypass equipment, a rapid switch and a reactor. The reactor is connected with the rapid switch in parallel to form a current limiting module; two ends of a winding of one side of the series transformerare connected into a line in series; a winding of the other side is connected with the current limiting module and the converter rapid bypass equipment in sequence; the voltage source converter is connected with the converter rapid bypass equipment in parallel; and two ends of at least one side of winding of the series transformer are connected with at least one piece of series transformer bypassequipment in parallel. The series compensator provided by the invention can effectively limit short-circuit current of a system through indirect putting of a current-limiting module, fault current that the compensator bears is reduced, and reliability of an alternating current system and the series compensator is improved; and the voltage class of the current-limiting module is low, breaking current of the rapid switch is small, and thus the series compensator has relatively good engineering practicability.