It is known that the "synchronization phenomenon" in which the phase angles of the rotors are aligned in a plurality of generator groups is deeply related to the stable supply of electric power.Specifically, when a certain generator is out of synchronization, the generator and surrounding generators cannot operate stably, and in the worst case, a serious event such as a power outage is caused.
In particular, renewable energy such as solar power generation is said to be difficult to maintain synchronization of generator groups because the amount of power generation fluctuates irregularly due to changes in weather conditions.In Japan, which is looking to introduce a large amount of renewable energy in the future, it is essential to analyze synchronization phenomena related to efficient power generation and transmission.

　Under these circumstances, in this research, we examined a series of research results on power network modeling, stability analysis, stabilization control, etc. from the viewpoint of mathematical theory called graph theory.Until now, the analysis of synchronization phenomena has mainly been performed by numerical simulation, but the research group focused on network symmetry in graph theory.As a result, it became clear that the symmetry of the power grid is the basic principle for realizing the synchronization of the generator group.

　In addition, based on the analysis of this power grid, we have developed a method for constructing an integrated model of the power network, which enables efficient analysis of the behavior of the generator group and optimal design of the control system.As a result, there are expectations for the development of a power grid design that can withstand the mass introduction of renewable energy.

Paper information:[Proceedings of the IEEE] Graph-Theoretic Analysis of Power Systems