2022年和2023年的3月16日午后到3月17日凌晨贵州省均出现了大范围强对流天气,冰雹、大风、短时强降水在2次过程中相伴出现.利用多源资料对这2次大范围强对流天气的环流形势、大气环境特征、雷达回波和云图演变特征等进行分析.结果表明:...2022年和2023年的3月16日午后到3月17日凌晨贵州省均出现了大范围强对流天气,冰雹、大风、短时强降水在2次过程中相伴出现.利用多源资料对这2次大范围强对流天气的环流形势、大气环境特征、雷达回波和云图演变特征等进行分析.结果表明:2次强对流天气均为高空槽东移过程中强干冷空气从500 hPa侵入,在地面辐合线的触发下造成;2次过程均有冷池出流自西北向东南移,使得对流发展东移,冷池前沿的地面辐合线附近是主要降雹区域,冷池移动的前沿是雷暴大风发生的主要区域;2次过程的0~6 km风切变(shear of wind from 0 km to 6 km,SHR 6)大于20 m/s、0℃层湿球温度(wet blub zero,WBZ)高度在3~4 km、-20℃层高度在6~7 km、订正后对流有效位能(convective available potential energy,CAPE)值超过1500J/kg、整层为上干下湿的“倒喇叭口”型大气不稳定层结分布;700 hPa、850 hPa相对湿度梯度大值区和ΔT700-500、ΔT850-500梯度大值区叠加区可作为冰雹落区预报和预警的指标;2次过程中直径大于20 mm的冰雹均为孤立对流单体产生,且都具有回波悬垂、有界弱回波或弱回波、大于50 dBz的强回波质心特征.展开更多
It has been known that DC arc faults pose a hazard in power electronics systems. Due to the fault current is lower than normal current load, series arc is more difficult to be discovered than parallel arc. The traditi...It has been known that DC arc faults pose a hazard in power electronics systems. Due to the fault current is lower than normal current load, series arc is more difficult to be discovered than parallel arc. The traditional methods of DC series arc faults detection have some disadvantages, such as large computation, long delay and easier influence by interferences. In this paper, a novel method with multi-scale morphological filtering was utilized for the fault detection of DC series arc. Compared to the tradition method, the proposed method is more simple and efficient. It was verified that it was convenient for field application of on-line monitoring and diagnosis with a good ability to prevent misjudgments from the environment interference.展开更多
文摘2022年和2023年的3月16日午后到3月17日凌晨贵州省均出现了大范围强对流天气,冰雹、大风、短时强降水在2次过程中相伴出现.利用多源资料对这2次大范围强对流天气的环流形势、大气环境特征、雷达回波和云图演变特征等进行分析.结果表明:2次强对流天气均为高空槽东移过程中强干冷空气从500 hPa侵入,在地面辐合线的触发下造成;2次过程均有冷池出流自西北向东南移,使得对流发展东移,冷池前沿的地面辐合线附近是主要降雹区域,冷池移动的前沿是雷暴大风发生的主要区域;2次过程的0~6 km风切变(shear of wind from 0 km to 6 km,SHR 6)大于20 m/s、0℃层湿球温度(wet blub zero,WBZ)高度在3~4 km、-20℃层高度在6~7 km、订正后对流有效位能(convective available potential energy,CAPE)值超过1500J/kg、整层为上干下湿的“倒喇叭口”型大气不稳定层结分布;700 hPa、850 hPa相对湿度梯度大值区和ΔT700-500、ΔT850-500梯度大值区叠加区可作为冰雹落区预报和预警的指标;2次过程中直径大于20 mm的冰雹均为孤立对流单体产生,且都具有回波悬垂、有界弱回波或弱回波、大于50 dBz的强回波质心特征.
文摘It has been known that DC arc faults pose a hazard in power electronics systems. Due to the fault current is lower than normal current load, series arc is more difficult to be discovered than parallel arc. The traditional methods of DC series arc faults detection have some disadvantages, such as large computation, long delay and easier influence by interferences. In this paper, a novel method with multi-scale morphological filtering was utilized for the fault detection of DC series arc. Compared to the tradition method, the proposed method is more simple and efficient. It was verified that it was convenient for field application of on-line monitoring and diagnosis with a good ability to prevent misjudgments from the environment interference.
