The invention discloses a light triggered thyristor (LTT) power unit, which has the characteristics that three single-phase thyristor power units are connected into one set of equipment for controlling reactive current; the single-phase thyristor power units are connected in a triangle; the phase control electric reactor of each branch is divided into an upper layer and a lower layer; the single-phase thyristor power units are connected into the upper layer and the lower layer in series. The LTT power unit of a breakover diode (BOD) is integrated in the LTT power unit. The triggering mode of the LTT power unit is laser triggering, so that the LTT power unit has the advantages of stronger antijamming capability, small maintenance amount, high reliability and small land occupation, and the possibility of false triggering is almost zero.