Key technologies for intelligent integrated controller of circuit breaker are studied with regard to the characteristics of intelligent protection of circuit breaker.Focuses are laid on the inverse-time protection based on the principle of thermal resistance reduction and the boundary switch function for cutting off the terminal user in fault

and the relative techniques are discussed in detail.The theory of enhancing reliability of power distribution is introduced.Therefore

isolation of the user in fault and resumption of normal power supply in the non-fault section are realized by making use of temporal variation of opening and closing circuit breaker.The controller communicates with other protection devices or PCs through USB interface or industrial RS485 bus communication interface with protocol Modbus.In addition

GSM communication modules are used for ultra-remote control of opening and closing switch and timely feedback of fault information.The intelligent integrated controller of circuit breaker may provide a support to information networking and intelligent grid.