基于邻域法对覆冰预报产品的评估

随着覆冰预报模型的发展,模型预报结果蕴含的预报信息更丰富,传统评价方法和指标已不能客观合理地评估现有预报产品。为充分利用现有覆冰预报产品,对比了传统评分方法和邻域法,并利用邻域法评估了覆冰预报模式对2016—2017年冬季四川电网覆冰的预报效果。结果表明:评估的预报产品可以较准确地反映线路覆冰的空间分布和时序变化,覆冰厚度偏高2～3mm;邻域法比传统评价方法更加合理和客观,评估结果减少了空报和漏报倾向,避免了传统方法评估导致覆冰预报产品不可用或可用价值低的现象;当覆冰厚度小于20 mm时,在距任意输电杆塔水平方向1～3 km的范围内预报数据均是可利用的;当覆冰厚度介于20～28 mm时,预报数据可用性较低,可能是由于覆冰观测样本极少导致的。利用邻域法评估覆冰预报产品有利于实现现有预报精度下覆冰产品的最大化利用,评估结果对实际生产中覆冰预报产品的利用具有参考意义,同时也是对预报模式的反馈,可为更具针对性的优化数值模式提供支撑。

Evaluation of Transmission Line Icing Prediction Products Based on Fraction Skill Score

With the enhancement of computing capacity and the development of power icing prediction model, the model can provide more rich prediction information. However, traditional evaluation methods and indicators are not objective and reasonable when it comes to evaluate the existing prediction products. To make full use of existing icing forecast products, we evaluate icing prediction products of Sichuan power grid by comparing with traditional grading methods in winter, 2016-2017. The results show that the selected icing forecast products can accurately reflect the icing spatial and temporal distribution though the prediction thickness is 2~3 mm thicker than the observations. Meanwhile, compared with the traditional method, the fraction skill score(FSS) is more flexible and more instructive for the electricity production and operation due to reducing of tendency to miss alarm rates and false alarm rates. In addition, forecast products are credible and reliable in the range of 1~3 km below 20 mm thickness. Few observed samples of 20~28 mm icing data lead to low availability of forecast products. Applying FSS to evaluate the existing icing prediction products is conducive to maximizing the utilization of icing products under the existed prediction accuracy. And it is significant for the use of existing prediction products during power network operation. Moreover, the evaluation results are also feedback to prediction model to optimize the numerical model.