Analysis Of The Desynchronization And Extension In Power Grid Based On Kuramoto-like Model

As the development of complex network theory, more and more scholars use complex network theory to study the nonlinear dynamic behavior of the power grid. Using complex network theory can extract the topological properties of a complex systems. A reasonable model can help us to understand the various phenomena and reveal the inherent characteristics and evolution of the power grid. These studies have a important impact on the stability of power grid maintenance.In this paper, we analysis of the desynchronization and extension issue of the power grid based on Kuramoto-like model, including the following aspects:1、Study the self-organized synchronization and the anti-disturbance ability in power grid. A Kuramoto-like model has been used for modeling the power grid and then we can get the dynamic equation of each nodes. In the IEEE30 bus system, the system operation states under different coupling strengths K have been observed. Study shows that if the coupling strength exceeds a critical value K≥ Kc, all the nodes in the system run at the same frequency Ω, the power grid is in synchronization, the larger the coupling strength, the better synchronzability. Then we study the anti-disturbance ability in power grid, we choose a node i randomly and change its power to pt+△p in IEEE30 bus system. This study found that if Ap is small, system can keep synchronization after the disturbance removal, but if △p is lager, system can’t keep synchronization.2、Study the desynchronization phenomena and the factors affecting the spread of desynchronization in power grid. Disturbing the No.26 node in IEEE30 bus system and triggering the nodes desynchronization. Then, we can observe the propagation of desynchronization in power grid. Study shows that the ω of No.26 node firstly deviates its stable state, and then the ω of No.26 node neighbors deviate theirs stable state. We find that desynchronization is triggered by the perturbation of one node and the spread to all network without control. And then,we change coupling strength K and perturbation △p to observe the effect of desynchronization. The result shows that the larger K and △p,the faster the desynchronization spread. In IEEE57 bus system, we study that effect of disturbing the node which has different degreed, and then we find that no matter the node type is generator or load, the smaller the degree of node, the slower the desynchronization spread, a negative correlation between the degree of perturbed node and the speed of propagation of desynchronization wave,but because of the complexity of the structure this relationship is not strict. And then, we puts forward the concept of node important degree, study the topologies of perturbed node and its neighbor nodes how to effect the desynchronization. We disturb the node which has different importance in IEEE118 bus system, and we find that the node with large importance is disturbed,the desynchronization spread faster than the same distribution of a node with small importance.3、Study the effect of two different distributed connection strategies on the power grids synchronous ability and anti-disturbance ability. we have considered the current research status and propose two kinds distributed connection strategies. The first strategy is that the distributed generations are connected to the load nodes with smaller degree (SDJ), the second is an opposite strategy, distributed generations has been connected to the load nodes with larger degree (LDJ).we add different numbers of DG(ρ) to the power grid and experiment in IEEE30 bus system、IEEE57 bus system and IEEE 162 bus system. Study shows that two kinds of strategies both can reduce the threshold of synchronization and the SDJ strategy can improve the synchronous ability better than the LDJ strategy in the same ρ. And then, disturbing the node in IEEE30 bus system、IEEE57 bus system、and IEEE 162 bus system, and then we find that when ρ≥40%, the network which connected with SDJ strategy will be more robust against the perturbations. Comparing the two strategies, the network which is connected with SDJ strategy can recover to steady states quicker.