计及风速与线路故障率周期时变特性的风电并网系统可靠性评估

Reliability Evaluation of Wind Power Integrated Systems Considering Periodic Time-varying Characteristics of Wind Speed and Failure Rate of Lines

目前在风电并网系统长期可靠性评估中,风速多采用威布尔概率分布模型,输电线路故障率多采用年均值故障率,其评估结果无法反映系统可靠性随时间的变化情况。提出了综合考虑风速和输电线路故障率周期时变特性对电网的影响进行可靠性评估。在风电场出力方面,建立了风速的时间周期时变模型,并根据风机输出功率与风速的函数关系进一步建立了风电场的出力模型;在输电线路故障率方面,通过统计气象引起的输电线路故障次数计算历史同期各月故障率,用曲线拟合模拟其变化规律,建立了输电线路故障率周期时变模型。基于上述两种模型,用蒙特卡洛模拟法,对风电并网系统的时变可靠性进行评估,最后用算例进行了验证,评估结果可为电网中长期调度、运维及检修决策等提供参考。

The Weibull distribution model of wind speed and the annual average value of failure rate of lines are currently used in reliability evaluation of wind power integrated system, but it cannot reflect the time - varying characteristics of system reliability. The ilffluence of periodic time - varying characteristic of wind speed and failure rate of transmission lines on power system is comprehensively considered. In the aspect of wind farm output, the periodic time - varying model of wind speed is established, and according to the functional relationship between output power and wind speed, output power model of wind farm can be determined. In the aspect of failure rate of transmission lines, the historical monthly failure rate is calculated by staffstie failure numbers of lines, and the periodic variation failure rate model of transmission lines is established through curve fitting method. Based on the proposed models and Monte Carlo sinmlation, the time -varying reliability evaluation of wind powerintegrated system can be achieved. The validity of the proposed method is verified by a case analysis. And the results of reliability evaluation can provide a reference for mid - long term dispatching and maintenance decision.