Jimu News.
Jimu News chief reporter Pan XihengThe rare low-temperature, rain, snow and freezing disasters have brought great challenges to the transportation sector during the Spring Festival, and have caused large-scale delays or suspension of high-speed rail. Li Hongmei, a management expert of the Electrification Institute of the Fourth Iron Institute, saidThe main culprit affecting the normal operation of high-speed rail is the icing of the catenary, which is also a global problem faced by all electrified railways. 
There are four modes of precipitation in nature - snow, rain, sleet and freezing rain, the worst of which is freezing rain, which freezes instantly when the rain falls. The speed at which freezing rain condenses into ice is extremely fast, and the lower it falls, the thicker and harder the ice on the ground becomes, and the speed of human protection is difficult to keep up with its freezing speed. Li Hongmei, a management expert of the Electrification Institute of the Iron Fourth Institute, introducedUnder such weather conditions, the wires above the high-speed rail to provide train power are all wrapped in a thick layer of ice, which is the worldwide problem faced by all electrified railways - catenary icing. The professional name of the wire above the high-speed rail is called "catenary", and the iron frame on the roof of the car is "pantograph", when the pantograph is raised and connected with the catenary, the high-speed rail can get power supply in the taxiing state. If the catenary is covered with ice, the conductivity is poor due to the uneven craters of the ice shell, and the pantograph will produce electric sparks (arcs) when collecting current from the catenary, which will cause burns and burns of the catenary in severe cases. 
Not only that, but the catenary is also affected by the normal gliding of the pantograph after the catenary is covered with ice, especially the high-speed rail uses a carbon slide pantograph with high-speed current receiving performanceIf the train is running too fast, the icing on the lower surface of the catenary can easily cause the hard and brittle carbon slide to break, which directly leads to the interruption of the train's power supply and the halfway lying down. Therefore, some netizens saw in the short ** that the roof of the high-speed rail sparked all the way to "turtle speed" with lightning speed, that is, the driver took "no way":Stopping will cause congestion on the entire line, and it is easy to cause the failure of the powered equipment when running, so you can only coast slowly. Li Hongmei said that after the catenary is iced, if you want to resume normal driving, you naturally have to find a way to remove the ice on the catenary, and there are usually three ways:One is to heat the ice melt with electric current, the second is to de-ice mechanically, and the third is to manually knock on the de-icing. All three methods require the train to be stopped, and the effect is difficult to resist the instantaneous freezing of the natural environment. Heating the ice melting by electric current is to melt the ice on the catenary wire by sending a certain current to the catenary to make it heat. The general principle is to connect the ice melting device and the icing line to the same circuit, so that the line is short-circuited and heats up to melt the ice. According to reports, before the national snow disaster in 2008, only a small part of the country's power grid installed ice melting equipment, after the snow disaster, part of the power grid lines in the southern region used the equipment. Although the ice melting device of railway catenary has been studied and tested, it has not yet been popularized and applied. Although the ice melting process is simple, it requires a lot of equipment and is expensive. For example, traction transformers, converter transformers and rectifier equipment, etc. In addition, it is very cumbersome to operateThe ice melting process takes several hours and is not yet able to cope with the thick ice. Because the ice is thick, it often melts inside, and there is a ring of ice crust on the outside. At the same time,The entire plant also faces the cost of long-term maintenanceSo there are certain limitations. 
At present, most of the railway transportation departments use mechanical de-icing, and drive a special EMU that can withstand ice scraping and do not damage the contact line to the track. Li Hongmei introduced,The round of low temperature, rain, snow and freezing weather in Hubei is more complex and severe, resulting in the ice layer on the catenary being too thick, and it is difficult for the mechanical de-icing of the pantograph to move forward. In this case, manual knocking can only be used to de-ice. The railway workers could only brave the freezing rain and rely on manual de-icing little by little. "Specifically, the section of the road that needs to be de-iced is first de-energized, and then the catenary worker directly hits the ice with a stick. Although there are still cases where the ice is broken off and then freezes quickly, it is still the most effective way to do so. It is understood that in the face of the challenges of the harsh environment, China Railway Wuhan Bureau Group has organized thousands of railway workers of different types of work to carry out 24-hour snow and ice removal on key equipment such as catenary, lines, and turnouts. Li Hongmei said that after the beginning of spring, the weather in Hubei will gradually improve in the next few days, the temperature will rise, and the plight of the ice covering the high-speed rail catenary will be alleviated. **Jimu News (Chief Reporter: Pan Xiheng) Correspondent: Zhang Qishan Editor: Chen Xizi Review: Zhang Xin.