Study Of The Synchronization And Stability Of Power Grids Based On The Angle Of Dynamics

In recent years,with the complex network theory has been gradually infiltrated into many different research fields,using complex network theory to study the nonlinear dynamic behavior of power network has become a hot research topic.In this paper,the nonlinear dynamic equations of power network and the theoretical knowledge of complex networks are combined to research the following aspects:distributed extension of power grid:recovery strategy of generator fault in power network,synchronization and stability of cluster network,synchronization and stability of power network at different times.Details are as follows:1.Research on distributed extension of power grid.First,when the number of distributed power plants is a certain value,and the power of distributed power plants is changed,observing the change of the synchronous critical coupling strength Kc and the minimum disturbance intensity ?Pmin of the system.Through simulation analysis,when the number of distributed power plants is a certain value,with the increase of the power of each distributed power station,the critical coupling strength K,of the system decreases firstly and then increases,and the minimum intensity of the disturbance ?Pmin of the system increases firstly and then decreases.That is the synchronization ability and anti-disturbance ability of the system enhance firstly and then weaken.When the number of distributed power plants is a certain value,there is an optimal value for the power of distributed power station,under this optimal value,the network's synchronization performance and anti-disturbance ability are best.Second,when the total power of distributed power plants is a certain value,observing the change of synchronization capabilities of the system when the number of distributed power plants is changed.Research shows,when the total power of distributed power plants is a certain value,with the increase of the number of distributed power plants,the synchronous critical coupling strength Kc of the system descends wavily,then gradually tends to be stable.2.When a generator breaks down in the power grid,the recovery strategy of the system is researched.Firstly,when the tolerance parameter has different values,the measure to be taken to restore the power system from the fault state to the stable operation is researched.Research shows,in the standard IEEE14 bus test system,when a generator breaks down in the power grid,when a>=1.25,in order to restore the faulted power grid,only need to increase the power of the other generators;when a<1.25,we need to remove different amounts of load capacity according to different value of tolerance parameters.In this paper,in order to restore the faulted power grid,the strategy that removing load node according to the degree of vulnerability is proposed.Then,the feasibility of the proposed method is verified by three aspects:the critical coupling strength Kc of the remaining subsystems,maximum absolute value of node frequency offset in failure recovery phase,the minimum load disturbance intensity ?Pmin of the remaining subsystems.Experimental results show that,when a node with small degree of vulnerability is removed,the self organizing synchronization ability and anti-disturbance ability of the remaining subsystems are stronger,and in the recovery phase of the system,the loss of power network equipment is smaller due to the frequency fluctuations than the results of a node with large degree of vulnerability is removed.3.Study on the influence of different connection modes on the synchronization and stability of the cluster network,the synchronization and stability of power grid at different time.First,study on the influence of different connection modes on the synchronization and stability of cluster network.In this paper,we get four kinds of different cluster connections by distinguishing the node types.In the cluster network,if the number of the node in a network is smaller,it is called A network,if the number of the node in a network is larger,it is called B network,when the generator node of the A network is connected with the generator node of the B network,it is called GG connection;when the load node of the A network is connected with the load node of the B network,it is called LL connection;when the generator node of the A network is connected with the load node of the B network,it is called GL connection;when the load node of the A network is connected with the generator node of the B network,it is called LG connection.Research results show that,the anti-disturbance ability of the cluster network which inter cluster connection mode is LL connection and the GL connection is stronger.Second,the synchronization performance and stability of power grid at different times are studied.In this paper,the day and before the middle of the night,this kind of time is called A class moments,later in the middle of the night,this kind of time is called B class moments.At two different times,with the change of coupling strength K,observing the changes of the average order parameter,and the minimum intensity of the disturbance ?Pmin of the system.Through simulation analysis,it finds that the synchronization performance and anti-disturbance ability of the system at B class moments is stronger.