# Design and Experiment of Dry-Ice Cleaning Mechanical Arm for Insulators in Substation
## 1 Introduction  
In the long-term operation of substation insulator, dust floating in the air is easy to adhere to the insulator surface to form a dirty layer, which is more serious in heavily polluted areas. In the fog, rain, snow, and other weather conditions, the insulator insulation performance is reduced, and pollution flashover accidents are easy to occur [1; 2; 3; 4]. With the aggravation of pollution, the deterioration of global climate and environment year by year, and the use of high-voltage power grid, pollution flashover accidents show a trend of high frequency and wide area, which brings great hidden danger to power supply safely [5; 6; 7; 8].  
At present, antipollution flashover measures at home and abroad mainly include antipollution flashover organic RTV (room-temperature vulcanized) paint, electrified cleaning, and manual cleaning. There are many researches and applications of antipollution flashover RTV paint [9; 10; 11; 12; 13; 14]. RTV paint can alleviate but cannot fundamentally solve the problem of insulator surface pollution, and then it also needs manual or electrified auxiliary cleaning. For the work of electrified cleaning, some substations have carried out the high-pressure water cleaning with fixed nozzles [15; 16; 17; 18]; there are fire-fightingor engineering vehicles modified into electrified water washing robots [19; 20; 21; 22; 23], which need to be driven manually, so that there are some safety risks. In other conditions, some special electrified water washing tracked robots are designed [24]. The United States, Australia, Israel, and some other countries, which adopts the helicopter water cleaning way, have passed the electrical discharge demonstration experiment in 500 kV equipotential and over-voltage. However, electrified working with helicopters is not only relatively expensive and complex, but also requires sufficient safety flight distance, so that it is difficult to achieve thorough cleaning [25; 26; 27; 28]. The method of high-pressure water washing realizes the electrified cleaning of insulator, but the cleaning ability for industrial pollution is poor, the operation effect is not good in the area of heavy air pollution, and it also wastes water-resources greatly, so that it is not suitable for the operation in dry and cold areas. In addition, some research institutions have carried out the research of insulator brush cleaning robots [29; 30; 31; 32; 33], which requires high precision of robot end positioning. Due to the design of end driving and transmission mechanism, the design of high-voltage-insulation is relatively difficult, and the cleaning effect of oil-pollution is not good [34].  
At present, due to the influence of cleaning effect and operation safety, the substation insulator mainly adopts the manual cleaning mode of power-cut condition (as shown in Figure 1b), however there are hundreds of insulators in each substation above 220 kV (as shown in Figure 1b), which greatly affects the safety and reliability of power supply and the intelligent construction of power grid. Therefore, it is imperative to develop a kind of electrified cleaning equipment for substation insulator.  
According to this case, this paper develops an electrified dry-ice cleaning mechanical arm for high-voltage substation insulators. This system carries on electrified ice cleaning operation of substation insulators by wireless remote-control mechanical arm, and uses dry-ice particles as medium to accelerate in high-pressure air flow, impacts the wash-needed surface of insulators to clean and remove pollutions, which possesses the advantages of good cleaning effect for pollutions, nonstop operation, and high cleaning efficiency, and it can effectively solve the problem of insulator pollution flashover in substation.