Study On Synchronous Performance Optimization Of Power Grids Based On Kuramoto-like Model

With the development and application of complex network theory,a large number of theoretical methods have been used in power network systems which becomes a new hotspot in engineering field.Researchers have applied complex network theory to power network topology analysis And provides the theory guidance for the power system structure and the safety improvement.Based on the second-order Kuramoto-like model and the complex network nonlinear theory,the synchronization and stability of the power grid are studied.The main contents are as follows:Firstly,the power distribution of generator nodes in a power grid is studied.The concept of the Exchange Power is introduced at beginning,After theoretical analysis and experimental simulation in IEEE 14 and IEEE57 systems,we find that comparing with the case that every generators generate power equally,we can improve the the synchronous performance of power grid system by reduce the power of those small degree generator nodes at the same time increase the power of those large degree generator nodes.But this adjustment is not linear,When the power of the small generator nodes is too small and the power of the large degree generator nodes is too large,the critical synchronous coupling strength may not drop or decrease,Therefore,there is an optimal value of the critical synchronous coupling strength of the system.Secondly,we studied Brace's paradox phenomenon in power grids.Brace's paradox phenomenon is rooted in the road traffic system where the increase of the line often makes the traffic can not develop in an ideal direction.Researchers name the local congestion phenomenon caused by increasing traffic lines as Brace's paradox phenomenon,which also exists in the power grid.First of all,from the point of view of dynamics,we analyze the causes of Brace's paradox phenomenon in power grid.The results show that,in general,the increase of the connected edges in the power grids will reduce the synchronous critical coupling strength value which can improve network synchronization,but the increase of some edges will increase the critical coupling strength value which will reduce the network synchronization performance,at this time Brace's paradox phenomenon is emerging.The next,we have done a lot of experiments of adding the connected edges on the IEEE 14 and IEEE57 systems,and the experimental results show that the probability of occurrence of Brace's paradox phenomenon while adding the connected edges between the generator nodes or between the generator node and the load node is greater than the probability of occurrence of Brace's paradox phenomenon while adding the connected edges between the load nodes.Lastly,we improved the research on the connection modes of the distributed power plants.In this paper,three connection modes of the distributed power plants(SC,LC,PC)are proposed.The SC connection mode:the distributed power plants are directly connected to the load nodes with the higher power demand;The LC connection mode:the distributed power plants are directly connected to the load nodes with the higher power demand,meanwhile we add transmission lines between the nearby distributed power plants;The PC connection mode:the distributed power plants are directly connected to the load nodes with the higher power demand,at the same time we add transmission lines between the nearby distributed power plants with a certain probability p.The second-order Kuramoto-liked model was used to simulate the dynamic model of the power system,the topological characteristics,the synchronization performance and the anti-interference ability of the IEEE 14 and IEEE 30 systems were compared.The results show that all the connection modes of the distributed power station can improve the synchronization ability and anti-interference performance of the power grid systems.However,in the three kinds of grid connection modes,study shows that when the number of distributed power stations is the same,the synchronizability and anti-interference performance of a grid with the LC mode are the best among the three types of connection strategies,and the synchronous critical coupling strength is the smallest,while the synchronization and anti-interference performance of a grid with the SC mode are the worst.The synchronization and anti-interference performance of the PC access network are in the middle.