Pollution flashover caused by long-term contamination and moisture of the transmission line insulators is one of the main dangers for the safe operation of the power system. To study the contamination characteristics of the insulators in different weather conditions enables us to understand the contamination conditions of the insulators and take effective measures to prevent the pollution flashover accidents. Through the artificial contamination test and air dynamic simulation of the XWP2-160 double-shed insulator and FC160P glass insulator, it is concluded the influence of pollution contamination characteristic and flow field distribution characteristic in different wind speed and wind direction. The main factors that affected the insulator contamination characteristic were also analyzed, which can provide some guidance to the configuration of transmission lines insulators and antifouling work.
Insulator contamination is one of many serious problems for power systems. Outages due to insulator contamination flashover may affect a wide area and continue for a long time. Also, the corona noise causes radio and TV interference. Therefore, efforts have been made by many around the world to prevent such phenomena. Presently, fog type and semi-conducting glaze insulators have been developed, and successfully used. However, the former cannot suppress the corona and the latter has a subject to study from the viewpoint of thermal stability in heavy contamination conditions. A new concept insulator, with a stress graded zone on the bottom surface, has been studied. It has been determined that a dry band is not formed on this stress graded zone and a long dry band is formed at the first rib. This means the insulator has a high discharge starting voltage and high contamination withstand voltage.
We prove that groups acting geometrically on delta-quasiconvex spaces contain no essential Baumslag-Solitar quotients as subgroups. This implies that they are translation discrete, meaning that the translation numbers of their nontorsion elements are bounded away from zero.