  Blockchain technologies are one possible avenue for increasing the resilience
of the Smart Grid, by decentralizing the monitoring and control of system-level
objectives such as voltage stability protection. They furthermore offer
benefits in data immutability and traceability, as blockchains are
cryptographically secured. However, the performance of blockchain-based systems
in real-time grid monitoring and control has never been empirically tested.
This study proposes implementing a decentralized voltage stability algorithm
using blockchain-based smart contracts, as a testbed for evaluating the
performance of blockchains in real-time control. We furthermore investigate
sharding mechanisms as a means of improving the system's scalability with fixed
computing resources. We implement our models as a proof-of-concept prototype
system using Hyperledger Fabric as our blockchain platform, the Matpower
library in MATLAB as our power system simulator, and Hyperledger Caliper as our
performance evaluation tool. We found that sharding does indeed lead to a
substantial improvement in system scalability for this domain, measured by both
transaction success rates and transaction latency.
