The Research Of Power System Transient Stability Analysis Based On Wide-area Measurement System

Observability of power system is improved with the development of the Wide-area Measurement System (WAMS), and new methods are proposed for transient stability analysis in terms of WAMS recently. In this thesis, reviewing the historical development and studiedly present condition of transient stability analytic method, a new method of PMU placement for transient stability analysis and a approach called trajectory analysis method are employed to analyze transient stability quantitively when the transient data are not obtained entirely by WAMS.Firstly, a grouping strategy based upon slow-coherency is developed for large disturbances. The weak places are identified based on slow-coherency and the relation between coherent generators and weak link of network is researched in order to assess transient stability by means of the inherent structural characteristic. It is shown that the network partitioning pattern in terms of inherent configuration is also obtained based on slow-coherency. Although faults are uncertain and the group formed changes slightly with respect to different faults, the set of critical cutsets can be determined. It is mainly determined by topological ability prior to faults to form the grouping for large disturbances.Secondly, a new method of PMU placement for transient stability analysis is proposed. The partial center of inertia (PCOI) of every individual group is established. According to the summation of kinetic energy between PCOI and generators, PMUs are placed on generators which kinetic energy trajectories are closest to the PCOI their respective group. The approximate values are assessed quantitively depending on indices in the whole. This method is active to PMU configuration project.Thirdly, the partial information measured by PMUs is employed to establish PCOI instead of COI. The stability index of trajectory analysis method is employed in terms of PCOI to analyze system transient stability. The effectiveness is verified bynumerical calculation result of New England 10-machine test system.