The Classification Principle of Galloping Probability Distribution Map in North China Power System

摘要

During the spring of 2010, the north of China was confronted with heavy winds, rain and snow severaltimes. Due to the poor weather condition, lots of galloping trips of transmission lines happened inthose areas. In order to prevent the damage to the power system caused by galloping in bad weathercondition, State Grid Company of China (SGCC) demands subsidiary companies to develop theresearch on drawing the probability distribution map of galloping in each administrative region,mainly based on the historical data of the galloping trips in the operated transmission lines. The regionwould be classified into 4 levels as strong galloping region, medium galloping region, weak gallopingregion and no galloping region. Meanwhile, preventive methods of galloping at each level werestudied.However, galloping was closely related to natural environment. Therefore, the classification method ofgalloping probability distribution only based on historical data seemed to be not reasonable. Besides,there was no historical data in some areas as transmission lines haven’t been built yet. In order torepresent the possibility of the occurrence of galloping correctly, North China Grid Company limited(NCGC), which is a subsidiary company of SGCC, researched on the classification principle ofgalloping occurrence probability to find a reasonable standard for galloping classification.In the research, natural condition was thought to be one of the most important factors in theclassification and the parameters of transmission lines should also be considered, while historical dataof galloping should be used for verification of the accuracy of the classification method and principle.In other words, only when the results of the galloping probability distribution classified based onnatural condition is mostly in accordance with the results based on historical data, the classificationmethod based on natural condition can be accepted and applied into practice.In our research, we firstly analysed the statistical data of weather condition and icing characteristic ofsome typical galloping areas and determined the major environmental factors, including landform,wind speed, temperature, humidity and the possibility of rime and glaze. Then, with the cooperation ofmeteorological department, we collected a large number of weather data of the areas in north China inthe latest 30 years. After the numerical statement, screening and analysis of these data, the research developed two methods to plot the galloping distribution map, one was based on the weighted averagealgorithm and the other was based on the statistical information of the galloping day. Then, optimizedby the historical data, the galloping level can be classified and the distribution map can be finallyplotted.As the meteorological data was collected from the regions of north China, this galloping map can onlybe applied into north China. However, the principle and drawing method can be referred to otherareas.