Key management is crucial to securing network information in substations. It is hard to set up a safe and efficient method in conformity with the actual situation of the substation. A light layered key management method is proposed according to the information exchange range and association degree. Proper tasks are assigned to control centers

substations and intelligent electronic devices(IEDs)by their computing and storage capacities in the proposed method to reduce communication and computation overheads. Key generation

allocation

updating and destruction are detailed. Finally the communication and computation cost and the storage key numbers required by every participating party are analyzed. This work is supported by National Natural Science Foundation of China(No. 51477057).