新能源临界短路比对电网运行参数灵敏度分析方法

Sensitivity Analysis Method for Critical Short Circuit Ratio of New Energy to Power Grid Operating Parameters

针对系统运行中临界短路比实际值伴随交流侧运行参数实时变化导致临界短路比经验值不够灵敏准确的问题,提出一种新能源临界短路比对电网运行参数灵敏度分析方法,以判断工程中常用临界短路比的准确性。首先,构建一种考虑静态负荷的交流侧戴维南电路数学模型和新能源临界短路比计算方法;然后,推导出新能源并网系统临界短路比对交流系统参数灵敏度分析方法;最后,通过算例分析表明负荷等参数变化对新能源并网系统临界短路比的计算值存在较大影响。所提方法弥补了临界短路比经验取值在系统实际运行中易因工况变化导致的指标不再灵敏准确的缺陷。

Aiming at the problem that the actual value of critical short-circuit ratio is not sensitive and accurate enough with the realtime changes of operating parameters on AC side,a sensitivity analysis method of new energy critical short circuit ratio is proposed to judge the accuracy of critical short-circuit ratio commonly used in engineering.Firstly,a mathematical model of AC side Thevenin circuit is constructed considering static loads and calculation method for the critical short circuit ratio of new energy sources;Then,the sensitivity analysis method of critical short-circuit ratio of the new energy grid-connected system to the AC system parameters is derived.Finally,example analysis shows that the changes in load and other parameters have a significant impact on the calculated value of critical short circuit ratio of new energy grid connected system.The proposed method makes up for the defect that the critical shortcircuit ratio experience value is not sensitive and accurate due to the change of working conditions in the actual system operation.