基于常规气象资料的小时标准冰厚模型及验证

摘要

在综合考虑雨凇和雾凇积冰增长以及热力融冰和升华脱冰的基础上,建立了一个基于常规气象资料的小时标准冰厚模型.模拟2008年和2013年浙江省两次严重电网覆冰灾害期间的标准冰厚,并用事故线路调查资料、电线积冰观测站和模拟导线拉力监测点的观测资料进行验证分析.结果显示:事故线路的最大标准冰厚观测值与模拟值相关关系达到0.01显著性水平,电线积冰观测站的日标准冰厚观测值与模拟值的平均绝对偏差小于0.6 mm,模拟导线拉力监测点的小时标准冰厚模拟值与观测值的决定系数为0.8093,均方根误差为0.8 mm.说明模型比较准确地描述了天气过程对电线积冰的影响,能够较好地反映标准冰厚的空间分布规律和时间变化特征.%The effective monitoring and early warning of ice on transmission lines are required to guarantee the reliable operation of power grid.However,due to the sparse coverage of wire icing observation stations,the regional ice loads can hardly be characterized by in-situ measurements.To solve this problem,an hourly standard ice thickness model using conventional meteorological data has been developed.In this model,the evolution of icing event is divided into different phases,namely accretion phase,persistence phase and shedding phase.During accretion phase,the ice weight increases by glaze and rime-ice accreting on power lines.During persistence phase,there is no change of ice weight.And in the phase of shedding,the ice weight decreases due to melting or sublimation.Each icing event includes at least an accretion phase and a shedding phase,and may also include other accretion,persistence and shedding phases.The simulation consists of three steps.The phase of icing event and the type of ice accretion (or shedding) is determined by hourly meteorological data.According to identified results,the variation of ice weight in the current hour is estimated using different methods..The variation is zero in the phase of persistence;the glaze and rime ice accretion is respectively simulated by adjusting Jones' simple model and Mackinnon model;the melting and sublimation ice is estimated using experimental equations presented by Farzaneh et al.The varied weight of current hour is summed with the ice weight of the previous hour to get the ice thickness of current hour.Using hourly meteorological data from more than 2000 stations located in Zhejiang and neighboring provinces,along with NCEP FNL analysis data,the model is employed to estimate the hourly standard ice thickness with 0.01°× 0.01° spatial resolution in Zhejiang Province during periods from 11 Jan to 20 Feb in 2008,and from 1 Jan to 10 Jan in 2013.Furthermore,it is evaluated and validated by the power system fault data,survey data of damaged transmission lines,wire icing observation,and the in-situ wire tension measurements.Results indicate that the model can well capture the influence of weather on icing events,and also well characterize the spatial distribution and the temporal variation of wire icing events.At the wire tension monitoring sites,the simulated hourly standard ice thickness is generally in agreement with measured values,with determination coefficient of 0.5209-0.9287(with a mean value of 0.8093),and root mean square error of 0.1-2.4 mm (with a mean value of 0.8 mm).