Based On The Theory Of Complex Network Power Network Stability Studies

Complex network science has become one of the most popular science at present for its forwardness and interdisciplinary nature. At first, the paper introduces the research status and the concepts that commonly used of complex network, and the Kuramoto model and the second -order Kuramoto model that frequently employed by power grid study. Then combining the dynamics of power grid and the current research of complex network theories in the power grid network, the paper conducts the research on the stability of power grid and this dissertation did a series of studies on it. The main contents of this paper are as follows:The influence of structural disturbance on the stability of network in the test network of IEEE14、39、57、118 is studied. By emulating the failure of single edge in the test power grid and observing the changes of frequency, phase and the overall phase sequence of the power grid, the paper studies the influence of the failure of single edge on the stability of power grid, figures out the invalid edges that present instability in all test network and their corresponding subsystems, and lists measures to sustain stability and conducts emulating to verify their effectiveness. Then, the paper studies the influence of the newly-added nodes on the stability of power grid by adding a new power station node in different access ways of random connection, researching on the new power station node influence on the stability of the power grid,power stations have access to the leaf node and non leaf node is connected to two kinds of strategies,the leaf nodes access, connection mode respectively, a new node random access; two is the new node and the node degree is three; the new node and the node lies the maximum number of nodes. In a non leaf node access, connection mode respectively are two new nodes and nodebetweenness edges corresponding to the largest connected; two is the two nodes corresponding to the new node and edge betweenness largest edge connected and disconnected, the original two node between the edges; the three is connected with the the two largest node degree,namely the new nodes connected with an edge node with maximum degree, the other edgeconnectivity large node, if the maximum degree of nodes have multiple, we randomly selectedtwo as a new connection object.We find that the system present instability when the failure of single edge causes the breakdown of the system. We also find that by taking the sample of the average condition of five tests, a newly-added node will increase the sequential parameter value of the network, which means in a statistical sense that newly-added nodes play a positive role in the network synchronization. Adding an node in the form of non-leaf requires less the minimum coupling strength for the synchronous operation. Under the condition of low coupling strength, the system cannot achieve complete synchronization when a new node connected with certain nodes accesses to the system. The experiment verifies that adding a new node will not only hinder the synchronous operation, but weaken the robustness of the system because of the structure change which gives rise to the increase of the minimum coupling strength that sustain the synchronous operation of the system.According to the disturbances of power network, we proposed a secondary power disturbance model to study the influence of power disturbance on the transient stability of power grid. This model is based on the premise that single power disturbance cannot make the system unstable, so that the magnitude of power disturbance should be 0.9 times the minimum average that of single disturbance on the instability of the system. Besides, in the IEEE57 power grid test, studies are carried out on the time intervals between two power disturbances, on the relations between the size of power and the stability of the system, on the time of sustaining stability when the second power disturbance causes transient stability and on the emulation of the measures to sustain stability. We find that not only the conventional instant power disturbances can cause transient stability, but single power disturbance can also bring up the same result when they are added together. Through further emulation, we find that there is a interval between two disturbances in different period, which has its maximum and minimum, and that the disturbances in this interval bring up transient stability problem. In addition, the minimum power disturbance to make the system unstable can also be confirmed in an appropriate interval with different duration, when the coupling strength of the system is determined. The timing of sustaining stability greatly affects its cost by emulating and comparing. In the end, through the emulating experience on the measures of sustaining stability, we verify the feasibility of these measures and make a comparison among them, and figure out the measure of sustaining stability is better when decreasing the power output of the breakdown node of plant station and immediately resuming its original output when the system becomes stable...