Three-phase five-column arc suppression coil, as a tune arc-suppression coil, use SCR to adjust inductance steplessly. Extreme tuning principle is usually used, but zero sequence voltage changes little in the vicinity of the resonance point, It is not easy to search extreme point accurately, so large deviation occurs between the measurement of capacitive current and the actual value. A new method for tuning is proposed in this paper in order to solve the problem, According to zero sequence voltage phase relations measured and the characteristics of unchanged damping rate in the system, the admittance diagram is constructed by tuning and capacitive current can be computed through admittance angle. MATLB simulation and experiment platform measurements show that precision of this method is higher than extreme value method.
