Research On Dynamic Performance Evaluation Key Technology Of The Generating Units Connected To Power Networks

With continuous expansion of the power grid size and increase of the number and type of the power generating units in China, the dynamic characteristics of the power grid become more and more complex. The generating units are the most important dynamic elements in a power system, whose dynamic performance after connected to the power grid has important influence on the security and stability of the power system. It has great significance to study and evaluate the dynamic performance of the units on fully understanding the dynamic operation characteristics of the power system, improving the level of coordination control of the network and power sources, and ensuring the safety, stability and economic operation of the power grid. The wide application of the wide area measurement systems provides real time synchronization information of the power systems, which provides the data base and technical conditions for the research and implementation of the dynamic performance evaluation of unit connected to the power network.In order to furtherly improve the accuracy of the simulation model and to improve the dynamic performance of the units, this thesis focuses on the relevant technology of dynamic performance evaluation of unit connected to power networks. The main research work is as follows:(1)With the measured data as the input signal of the hybrid simulation, the model parameters can be verified by comparing the simulation results with the corresponding measured data. From the aspect of dynamic simulation accuracy evaluation, the hybrid simulation technology of unit level and control module level based on power constraint and variable impedance method is studied. The realization method of the hybrid simulation technology of unit level and control module level are presented. The shortcomings of the accuracy evaluation method of existing simulation model is further studied, the selection principle of simulation error indicators is summarized, and the accuracy evaluation index system for the simulation model of different conditions of generating units is established.(2) The dynamic performance evaluation index set of the unit excitation systems and speed governing systems is constructed. The dynamic performance evaluation method of the conventional units connected to power networks is investigated by using intuitionistic fuzzy decision, and the index weight model based on intuitionistic fuzzy sets is constructed. The optimal weight of every performance index of the unit excitation systems and governor systems is determined by model optimization. The comprehensive evaluation of dynamic performance of the units connected to power networks is realized by employing the order preference technique of the similarity to ideal solution method (TOPSIS) based on the absolute ideal solution. Based on the simulation data and the actual dynamic monitoring data, the effectiveness of the proposed dynamic performance evaluation method is analyzed and verified.(3) The evaluation index set of dynamic performance connected to power networks such as the dynamic reactive power support capability and the dynamic var compensator (SVC/SVG) response performance is researched. The comprehensive evaluation method of wind farm’s dynamic performance connected to power networks based on coefficient variation method and TOPSIS method is proposed. The coefficient variation method is used to determine the performance index weight of wind farm. Then, TOPSIS method is applied to calculate the relative closeness of the sample points to the optimal sample points. By closeness sorting, the effective and objective comprehensive evaluation of wind farm’s dynamic performance connected to power networks is realized.(4) A platform for unit dynamic performance evaluation is studied and developed. On the basis of the research on the conventional units and online evaluation module of the wind farms, the accuracy evaluation of the simulation model of the unit and its control system, and the dynamic performance evaluation of conventional unit and wind farm are realized, which have been applied to practical engineering. The practical application results have shown that the developed dynamic performance evaluation system has a good actual engineering effect.