Analysis Of The Microgrid Voltage Stability Based On The Singular Value Decomposition Method Of All Nodes Jacobian Matrix

Microgrid is composed of a series of distributed generation system, storage system and load of the micro power grid. Because the distributed generation has many advantages, such as saving investment, flexible generating method and does not pollute the environment, microgrid is developing rapidly in recent years. In order to ensure the reliable operation of microgrid, the voltage stability is the key to guarantee. Due to the structure of microgrid and the traditional power grid has differences, such as the stability of microgrid will be affected when micro power changes. Therefore, there is important theoretical and practical significance to study the microgrid voltage stability.Based on the analysis of voltage stability analysis methods for power system, the second chapter points out the advantages and disadvantages of sensitivity analysis method and the continuous power flow method. And it is pointed out that the traditional singular value decomposition method of Jacobi matrix based on the analysis of the matrix without balance node, without considering the equivalence between balance node and other nodes according to the law of the power supply. Based on the analysis on the characteristics of micro power, the third chapter puts forward a new node type called PI node in the power flow calculation of microgrid.And a method is proposed to make PI node equivalent to a PQ node, the method simplifies the power flow calculation.Analysis of the microgrid voltage stability based on the singular value decomposition method of all nodes jacobian matrix is proposed. And the solution of all nodes jacobian matrix is proposed, including a detailed derivation of the singular value decomposition method and its mathematical model, and the calculation method of the minimum singular value and its index. After calculating the singular values and singular value vector, the fourth chapter analyzes the application of them in static voltage stability analysis,Such as the identification of voltage weak nodes, the critical region, the weak transmission line, and the sensitive generator or SVC. The fifth chapter compared with the traditional singular value decomposition method of jacobi matrix, and verifys the accuracy of this method.According to the singular value decomposition method of all nodes jacobian matrix, the fifth chapter has carried on the simulation computation and analysis.Based on an actual microgrid system as an example, write the simulation program and simulation, and the simulation results are compared and analyzed. Through the preparation of the simulation program and simulation, the simulation results are compared and analyzed based on an actual microgrid system.All nodes Jacobi matrix of microgrid is singular in the operation point of the system, using the singular value decomposition method for the analysis of voltage stability of the microgrid is more reasonable and comprehensive. The sequence of weak nodes of microgrid static voltage stability based on all nodes Jacobi matrix is always the same, with the current balance of nodes selected in the calculation and change. It makes up the defect that the sequence of weak nodes of traditional Jacobi will change when the selected balance node changes in power flow calculation.