Low Frequency Oscillation Analysis Based On Network Energy And Identification Of Main Oscillation Path

In recent years, with the construction of the regional power grid, the increase ofpower system capacity and voltage grade and the use of all kinds of new technology,power system presents a hierarchical power grids, block, high dimension and thecharacteristics of strong nonlinear which makes the grid structure becoming more andmore complicated.Power system has already completed interconnection betweenregional power grids while transmission power on the tie lines is huge and the tielines control is complicated, which has produced many uncertain factors and hasbrought more security hidden dangers for power system, making the problem ofpower system low frequency oscillation becomes obvious day by day.Therefore,lowfrequency oscillation problem appearing at the progress of networking is graduallygiven wide attention by power operation workers and research scholars. Making therational and effective scheme of identifying the main oscillation path is the corecontent of this study.Firstly,the establishment of network energy function for low frequencyoscillation analysis provides new ideas and new methods. Network energy based onbranch potential energy sets up generator node potential energy and branch networkenergy function, at the same time put forward to the identifying index of judging themain oscillation path of the power system, provides a solid theoretical foundation tothe research of this paper. In this paper, the network energy function based on branchpotential energy method is being supplement, while the meter and the resistance lossand load energy is mainly considered in order to make the whole energy calculationmore complete.Secondly,the distribution character and variation law of branch network energyand generator node potential energy is being analysised in the low frequencyoscillation.When combined with the character of the generator node potential energy, the derivation and demonstration of generator node oscillation index is carried out,the physical meaning of that being described. At the same time, branch oscillationindex based on the branch nerwork energy is being the supplement and perfect of thenew index,which make the study and analysis of network energy function more clearin the low frequency oscillation. The main oscillation index based on the branchoscillation index and generator oscillation index is proposed. The identifying schemeof main oscillation path based on the main oscillation path index is established,whichrealize the determination of the main oscillation path.Finally,by way of China electric Power research institute and development ofPower System Analysis and synthesis Software (Power System Analysis SoftwarePackage, PSASP), the simulation Analysis was carried out on the four machine twoarea,the8machine36node and the fixing8machine36node,which proved theeffectiveness of the indicators and the scientific nature of the method.