一种微网静态电压稳定判别指标研究

微网运行区别于高压互联电网,其微源与传输线路等特征决定了网络电压、频率等运行参量的独特性,微网静态电压稳定判别是评价微网稳定运行的关键指标。针对微网网架结构和运行特点,结合戴维南等值算法,提出一种适用于负荷连续变化的微网节点电压稳定性实时判别指标。该指标以同步相量测量方式为指标推导模型中的所需参数赋值。建立迭代修正量并计算获取运行参数与线路参数,以线路传输功率极限为边界,实时判别所构建的指标值,最终实现系统静态电压稳定性评价。该指标计算过程中在线识别网络参数,计算速度快,能够满足微网系统静态电压稳定性在线判别的需要。以3机9节点系统对指标正确性进行验证,并通过应用于13节点微网系统仿真,分析了微源的节点类型、位置、容量对微网静态电压稳定性的影响以及指标应用的合理性。

Judgment of Static Voltage Stability for Microgrid

The characteristics of microsources and transmission lines in microgrids decide the dift~rences of operating parameters com- pared with that in high woltage transmission grid, such as buses w）ltages and frequencies. However, the static voltage stability of a microgrid is one of the significan! symbols to evaluate the microgrid stable operation. A real-time index based on Thevenin equivalent algorithm is proposed to analyze static voltage stability for microgrid with continuous load growth. This index uses local electric syn- chronized phase measurement to assign the parameters in principle model of index, iterative correction an（ Thevenin equivalent branch. The transmit power limit is used as the confine of static voltage stability by real time calculation of the index. The index could meet the needs of real-time static voltage slability judgment for microgrid with the advantages of rapid calculation and no need for all the network parameters. Thor three sources nine nodes system is used to prove correctness and rationality eft the index. A thirteen nodes micrngrid is built to analyze the influenc, e of bus types, positions and capacities of microsources to the static wfltage stability, with a effectiveness proving for the index.