  As the last resort of emergency control, controlled islanding is an effective
means of preventing fault-propagation and a system-wide blackout. However,
conventional AC transmission lines are unavailable to be employed for power
exchange between these islands. To make full use of the DC power modulation
capability of VSC-HVDC links, a new controlled islanding model is put forward
for an AC/VSC-HVDC hybrid grid to minimize the composite power-flow disruption,
in which the DC-terminals belonging to a VSC-HVDC link are placed in different
islands. To solve this model, a semi-supervised spectral clustering-based
approach is proposed by transforming the problem into a weighted undirected
graph segmentation problem. The novelty of our work is to find an optimal
islanding solution in real time such that the power exchanges between islands
are implemented via a VSC-HVDC link to reduce the generation-load imbalance.
The simulation results on the IEEE 39-bus system and a real-world system verify
the effectiveness and superiority of the proposed approach.
