Abstract: In order to solve problems of inconvenient junction regulation and lack of on-line current measurement function of man-operated multitap arc suppression coil with nine joints and no loads used in a distribution network, a microcomputer-controlled TSC arc suppression coil was developed. Capacitors with different capacities are connected in parallel with secondary coil through thyristor in the arc suppression coil, and quick and dynamic tuning of compensated power network is realized by use of the thyristor. Meanwhile, the function of real-time current measurement of the arc suppression coil is realized by use of a microcontroller as well as function of line selection for single phase grounding fault based on the line selection method of connecting mid-resistance in parallel. The application showed that the arc suppression coil has accurate tuning, high reliability and high correct rate of line selection.