Security enhancement of time synchronization and fault identification in WAMS using a two-layer blockchain framework

Abstract

In this paper, we propose an auxiliary two-layer blockchain framework to improve the security and reliability of Wide Area Measurement Systems (WAMS) in smart grids against adverse manipulation of time synchronization and interference with fault identification. The framework benefits from the blockchain’s inherent advantages, such as distributed storage, consensus mechanism, and avoidance of single-point of failure while addressing typical challenges of employing blockchain technology in smart grids, such as the limitation of computation power and the high bandwidth requirements for data exchange. In the first layer of the proposed architecture, the security state of the system is determined based on the state opinion of Phasor Measurement Units (PMUs), using a consensus mechanism. Then, in the second layer, Phasor Data Concentrators (PDCs) use the first layer opinion to preserve the proper WAMS operation when some of the PMUs are compromised. In this setting and by utilizing a co-simulation testbed, we show the effectiveness of using smart contracts whereby PMUs and PDCs can reliably communicate and aggregate smart grid measurements while time synchronization and fault identification functionalities are appropriately maintained. We also evaluate several deployment scenarios and provide corresponding recommendations for the security enhancement of WAMS. Finally, we detail a fortification strategy that the Power System Operator (PSO) can use to harden the blockchain network, based on an adversarial model.