Prevention and Control Measures for Pollution Flashover of Transmission Lines

1. The importance of timing selection for anti-pollution flashover cleaning of transmission lines

For the lines that do not meet the conditions of "cleaning with salt density", the anti-pollution flashover should be arranged before the pollution flashover season; The research and testing of saturated salt density should be done during the cleaning cycle; for power transmission equipment with insufficient creepage distance and no RTV and silicone umbrella skirts, the "sweep must be done every stop" should be adhered to. Power failure cleaning insulators should not only meet the minimum fortification to prevent insulation flashover accidents outside the power grid under normal weather conditions, but should grasp the timing of cleaning and improve the quality of cleaning. The best cleaning time every year is from mid-November to mid-December. For example, the cleaning time of a line insulator is January, and the anti-pollution flashover is an improper cleaning time. Therefore, for important lines and substations, the timing of power outages must be reasonably arranged to achieve the best cleaning effect.

2. Prevention and control of pollution flashover of transmission lines to ensure the quality of cleaning

Do a good job of cleaning some lines that have not yet been adjusted for climbing, have no margin for climbing, and power transmission equipment with insufficient insulation configuration. It is recommended that the following methods should be adopted for line power outage cleaning in the future: replace linear insulators with composite insulators, and replace tensile insulators with RTV coating. insulators, or clean the insulators on the ground and spray RTV coating. Practice has proved that only the above methods can ensure the cleaning quality and fundamentally improve the cleaning effect. Timely and timely to ensure the effectiveness of cleaning. The effect of power outage cleaning is closely related to the external insulation configuration level, meteorological conditions and external environment of overhead power transmission equipment. According to the standard of cleaning and configuring external insulation once a year, only when the configuration is in place and the cleaning is effective, pollution flashover accidents are not easy to occur. Once a certain link is out of control, pollution flashover accidents are difficult to avoid.

Lines using composite insulators may not be cleaned, but their performance should be monitored regularly. If the pollution is too heavy or the hydrophobicity is obviously ineffective, it should be replaced in time or repainted over time; the cleaning cycle can be extended for the equipment using the silicone umbrella skirt, but the cleaning cycle and method need to be carefully studied.

It is suggested that while improving the insulation configuration level of important lines, all localities should actively promote the experience of "cleaning with salt density" for general lines. According to the development of the power grid, the anti-pollution flashover work of the power grid depends on the large-scale cleaning work, which should be gradually reduced as the external insulation configuration of the power transmission and transformation equipment of the power grid gradually "reaches the standard", until it is transformed into a maintenance measure for the temporary elimination of equipment shortages.

At this stage, the cleaning work is mainly carried out according to the annual pollution level classification and external insulation verification, combined with the power transmission and transformation equipment power outage maintenance work plan, and generally does not arrange cleaning work separately. For some power transmission and transformation equipment with weak links in the external insulation configuration according to the new pollution level classification, including those with increased pollution levels, those with grade C or above that are not compounded, those with insufficient creepage distance after multiplying double strings and shape factors, and special Power transmission and transformation equipment in heavily polluted areas (such as metal dust accumulation, cement accumulation and agglomeration), carry out cleaning work. There are limitations to cleaning. Some lines where pollution flashover occurred were cleaned by power outage within a year before pollution flashover. Although a lot of cleaning work was done, the occurrence of pollution flashover could not be prevented. On the one hand, it shows the seriousness of environmental pollution. When the self-insulation level is low, it is difficult to ensure safe operation only by the cleaning and maintenance of the operating unit. In addition, some main lines have few power outages and cleaning opportunities, and the time is greatly limited. The number of composite insulators is quite large, and the production personnel are generally biased. It is difficult to clean in a short time, and it is even more difficult to ensure the cleaning effect for insulators with serious fouling and grooves under the umbrella.