Abstract: In view of problem that closing coil in control loop of breaker often happens burnout when breaker of 10 kV capacitor bank makes breaking-closing control operation, the paper proposed an optimal design scheme of double control loops of closing coil of breaker. The scheme adds standby closing control loop in original closing control loop of breaker. When main closing coil is burnout, standby closing coil is charged to close breaker. The standby closing control loop series signal relay which can send out fault signal after main closing coil is burnout and can ensure terminal voltage of standby closing coil is uniform with one of main closing coil. The actual application shows that the optimal design scheme solves problem that closing coil of breaker cannot close timely after it is burnout and ensures normal on/off of capacitor bank.