Researchers Cut Quantum Resource Demand for Power Grid Islanding

A new method limits the spread of disturbances in electrical grids through controlled islanding, partitioning a compromised grid into connected, electrically sustainable islands. Classical methods face sharply growing computational costs as network size and island count increase. Quantum optimisation offers an alternative for exploring this combinatorial partition space. However, monolithic quantum formulations encode all assignment decisions in one circuit, causing qubit demand and circuit complexity to scale with network size. In this study, Yuqi Jiang of Tsinghua University and colleagues propose a qubit-bounded sequential distributed quantum approximate optimisation algorithm (QAOA) framework to tackle coherent controlled islanding under limited quantum resources. It formulates the optimal islanding strategy through a series of sequential QAOA optimisations. A five-fold reduction in qubits needed for controlled…