Cyber Layer Upgrade in Power Systems to Support Semi-Quantum Key Distribution

This paper investigates semi-quantum key distribution between local control centers and the substations in power systems to encrypt and decrypt critical measurements and control commands. We study the problem of allocating a minimal number of quantum servers and fiber links on a pre-existing cyber layer to satisfy the minimum required key rate in the presence of an attacker. The problem is formulated as a binary optimization program that upgrades the classical cyber layer of power systems to support semi-quantum key distribution. Due to the complexity of the allocation problem, we developed an optimal allocation strategy following a genetic algorithm. We examined the proposed allocation strategy on the cyber layer of the IEEE 14-bus and IEEE 39-bus test systems. Our results demonstrate that the target key rate can be achieved at different attack levels with a number of quantum servers and fiber links that is 33% and 21 %, respectively, less than a benchmark for the IEEE 14-bus system. Our results demonstrate that the target key rate can be achieved at different attack levels with a number of quantum servers and fiber links that is 67% and 19%, respectively, less than a benchmark for the IEEE 39-bus system. Our results also demonstrate that the proposed solution requires 52.17% and 54.65% less upgrades compared with QKD for the IEEE 14-bus and IEEE 39- bus systems, respectively.