基于特征模型的微电网并网动态等效建模方法研究

Microgrid equivalent modeling is the basis of the dynamic analysis of the power system which contains multiple microgrids. The mechanism modeling method has some limitations because of the new features of microgrid, e.g. diversity of structural form and variability of operation mode. And the diverse and complex equivalent model renders the parameters difficult to be precisely estimated. Hence, the proposed project plans to study characteristic modeling theory, which compresses the high order characteristics information into the low order system without loss information, and gives the equivalent model of microgrid. Multiple scenarios technique will be studied to reveal the natural relationship between the different operations of microgrid. Eventually we will build the microgrid dynamic equivalent modeling method based on the non-mechanism characteristic model. The studies provide theoretical support for the real time simulation and steady analysis of power system with multiple microgrids connected. The major tasks can be described as follows: (1) Single microgrid system equivalent characteristic modeling under connected mode. (2) Multiple characteristic models equivalent aggregation. (3) Characteristic model updating under different microgrid operation conditions. It will provide theoretical basis and experimental verification for the application of the proposed modeling method in power system dynamic simulation as the three major tasks being accomplished.

微电网等效建模是含大规模微电网并网接入电力系统安全稳定分析的基础。微电网网络结构多样、运行控制多变，致使利用传统机理等效建模方法得到的微电网并网模型形式多样、结构复杂，参数难以准确辨识。为此，本项目以微电网整体为研究对象，利用特征建模将微电网系统高阶特征量压缩至低阶系统又不丢失特征信息，建立微电网等效特征模型；提炼微电网系统运行的场景特性，利用场景理论明晰不同运行场景间的内在联系。提出基于非机理特征模型的微电网并网动态等效建模方法，为含多微电网接入的电力系统实时仿真和安全稳定分析提供理论支持。重点研究：（1）单个微电网并网等效特征建模；（2）多个微电网特征模型的等效聚合；（3）不同运行方式下微电网聚合特征模型修正。为该方法在实际电力系统动态仿真中的应用打下扎实的理论基础和实验验证。

微电网等效建模是含大规模微电网并网接入电力系统安全稳定分析的基础。微电网网络结构多样、运行控制多变，致使利用传统机理等效建模方法得到的微电网并网模型形式多样、结构复杂，参数难以准确辨识。为此，本项目以微电网整体为研究对象，针对微电网并网接入的等效建模问题，提出了基于特征模型的微电网等效建模方法，利用微电网内部、外部故障扰动激发微电网内部元件及控制系统的动态特性，构建微电网整体等效特征模型，采集并网接入点的动态数据，利用非线性系统辨识方法确定特征模型结构和模型参数，验证了利用特征模型进行微电网动态特性描述的可行性。针对多微电网并网特征模型的等值聚合问题，研究了基于Z变换的系统传递函数建模过程，提出特征模型等效聚合方法对微电网特征模型进行结构和参数的等效计算，实现多特征模型的等效聚合，同时分析了并网元件电气特性对微电网特征模型以及特征模型等效聚合过程的影响。针对微电网特征模型的时序性，研究了基于马尔科夫链随机概率统计微电网运行特性，构建微电网运行概率场景并利用K-means进行场景聚类实现场景消减，建立不同运行场景间的内在联系，实现不同场景建特征模型的修正。本课题的研究为含大规模微电网的电力系统仿真分析中微电网等效模型的建立提供借鉴和思路。