基于分岔理论的负荷模型对交直流混联系统电压稳定性的影响

为研究区域负荷模型对交直流混联系统电压稳定性的影响，以3机9节点交直流混联电力系统为例，建立考虑系统各元件动态特性的数学模型，采用分岔理论与局部参数化的延拓法相结合的方法对系统的平衡解流形进行追踪，并对影响系统稳定的鞍结分岔点、霍普夫分岔点进行搜索和检测。在此基础上，针对不同负荷增长方式对电压稳定性的影响进行研究，重点分析比较国家电网各区域电网调度部门、规划部门所采用的负荷模型对电压稳定影响的异同。研究表明：以全网负荷同比增长方式增加负荷时系统静、动态负荷裕度最小，最不利于系统的稳定性；随着负荷模型中异步感应电动机比例的不断增加，分岔边界曲线前移，各类型分岔点出现时间缩短，系统的电压稳定裕度减小，电压稳定性将受到更大的威胁。

Influence of bifurcation theory based load model on voltage stability of AC/DC hybrid system

In order to research the influence of regional load model on voltage stability of AC/DC hybrid power system, a mathematical model considering the dynamic characteristics of each component in the system is established by taking a 3-generator 9-bus AC/DC hybrid power system as an example. The system equilibrium solution manifold is tracked by combining bifurcation theory with continuation method of local parameterization, and the saddle node bifurcation and Hopf bifurcation which affect system stability are sear-ched and detected. On this basis, the influence of different load growth modes on voltage stability is resear-ched, and the differences of load models adopted by the dispatching departments and planning departments in each regional power grid of State Grid Corporation of China are emphatically analyzed and compared. The research shows that the system static and dynamic load margins are the smallest when the load is increased by the year-on-year growth of the whole grid load, which is most unfavorable to the system stability. With the increasing proportion of induction motor in the load model, the bifurcation boundary curve moves forward, the occurrence time of each kind of bifurcation point is shortened, the system voltage stability margin is reduced, and the voltage stability will be more threatened.