The DC transmission system contains new energy field stations. These sites are equipped with dynamic reactive power compensation devices. This device has reactive power inversion characteristics which could contribute to the transient overvoltage of the AC system when commutation failure happens. First, the transient voltage of the DC transmission system are spectrally analyzed and their harmonic dominant frequencies are acquired. Next, the phase frequency characteristics of the SVC control system are analyzed. The analysis reveals the mechanism of SVC hysteresis properties. The hysteresis characteristic is the root cause of SVC reactive power inversion when commutation failure happens. On this basis, strategy for capacitor switching is proposed. During the recovery of the voltage, part of the capacitors are removed, thus suppressing the SVC reactive power inversion. Finally, the simulation results verify the effectiveness of the strategy.