In this paper

the principle of thyristor controlled transformer（TCT）type adjustable reactor is introduced and the working process and harmonic characteristic of TCT with three-phase fourwire connection at LV winding. TCT simulation model is set up by the use of electromagnetic transient simulation software PSCAD to simulate operation process of the device

and obtain harmonic feature of system current injected by TCT at different trigging angle

which provides an important reference for design of the connection model of TCT and lays a good foundation for designing and manufacturing low harmonic TCT.