Current transformer

The utility model provides a current transformer, and relates to the technical field of current transformers. The current transformer provided by the utility model comprises a plurality of coil groups which are connected in series; each coil group comprises two PCB type Rogowski coils which are connected in series; each PCB type Rogowski coil comprises a PCB framework which is annularly arranged, and a first bonding pad and a fixed bonding pad which are respectively arranged on the two surfaces of the framework; two adjacent PCB frameworks are directly welded through the fixed bonding pads, so that two adjacent PCB type Rogowski coils are connected in series and fixed to form a laminated plate; a printed conductor is wound in the PCB framework, the first bonding pads serve as a measurement signal connecting end and/or a protection signal connecting end of the current transformer, when a protection signal is output, one first bonding pad and the other first bonding pad serve as output ends of the protection si