Intelligent Maintenance Free Super Capacitor DC power supply uses super capacitor bank as energy storage device to provide DC24 / 48V DC power for distribution automation of smart grid, which can meet the power supply of distribution automation terminal equipment and switching power supply of operating motor, make up for the shortage of battery and meet the DC power supply requirements of intelligent distribution network. In this scheme, super capacitor is used as energy storage element, which operates online; Supply power to DTU and opening control motor synchronously with control power supply main circuit; Good transient power characteristics, long service life, good temperature characteristics, maintenance free; Compared with battery, supercapacitor has many advantages which can not be compared with battery. (1) It has very high power density. (2) Fast charging. (3) Long service life. (4) Excellent low temperature performance. (5) The materials used in supercapacitors are safe, non-toxic, environmentally friendly and maintenance free. The batteries need to be maintained frequently, and the discarded batteries bring great harm to the environment.