In view of such problem as voltage mutation and power fluctuation due to uncertain load in distribution network

the application of super-capacitors in power supply reliability of distribution network is studied in this paper.The energy storage system of super-capacitor consisting of super-capacitor banks

DC/DC inverter and grid converters is constructed on the basis of the charging and discharging characteristics of super-capacitor.For achieving power exchange between super-capacitor and distribution network

the current bidirectional control strategy of DC-DC converter based on inductance current inner loop control and capacitance voltage outer loop control is studied.For DC/AC converter

the method of specified power is adopted.The power switching and tracking is achieved by the outer loop controller and feed-forward compensation of disturbance voltage in power grid by the inner loop controller.On this basis

the decoupling control of current is achieved by introducing compensation terms of d-axis and q-axis voltage.It is shown by the simulation result based on the control strategy in this paper

that the supercapacitor has a certain ability of reactive power compensation and active power compensation

can restrain voltage fluctuation and ensure the stability and reliability of power supply.