Abstract:The goal of full awareness of grid status means the widespread application of IoT technology in the grid. A large number of IoT terminals are connected to the network through sensing technology, communication technology, and computer technology. The number of IoT terminals connected to the grid is growing rapidly. The distribution of power Internet of Things terminals presents the characteristics of large number, wide area, and complex data collection, which are easy to be broken through and invaded by attackers, and traditional centralized authentication has problems such as single point of failure and performance bottlenecks. This paper uses blockchain technology to develops and applies technologies such as DID digital identity based on terminal identifier, DID parser adapted to multiple sources of blockchain, zero-knowledge proof based on terminal credential information, device management based on machine learning algorithm, and designes a blockchain-based security authentication system for power Internet of Things terminals. The system has been successfully applied in the power grid, realizing the decentralization of IoT device access authentication, reducing the network security risk of device access, reducing the cost of centralized infrastructure construction and maintenance, and improving the work efficiency of operation and maintenance personnel.