No abstract

No abstract

No abstract

In recent years, the performance of polluted suspension insulators operating in coastal foggy regions has attracted attention because of the occurrence of flashover. Surface wetting by salt fog accretion increases the surface conductivity and degrades the flashover performance of insulators. Normally, the effect of conductivity under fog condition and pre-contamination on the flashover of polluted insulators are analyzed separately. However, this does not reveal the flashover behavior in salt fog, which requires further research. This paper describes salt fog experiments with an AC test voltage conducted using polluted suspension insulators in a 110-kV power system. The electrical strength performance of sample insulators with salt fog treatments is analyzed, and the effects of salt deposit density (SDD) and the conductivity of fog water (CFW) on the flashover of three types of suspension insulators are studied. The concept of additional SDD is proposed to quantify analyze the effects of salt fog. The results show that there is less dependence on CFW at higher pollution levels than at lower pollution levels. That is, the effect of CFW on U 50 can be neglected for SDD>0.15 mg/cm 2 , whereas CFW has a strong effect on U 50 for SDD<0.15 mg/cm 2. CFW has a greater influence on the critical flashover voltage of ceramic insulators than on that of silicone rubber insulator. A model for calculating the critical flashover voltage of insulators is proposed by considering the combined effect of CFW and pre-polluting SDD.

Icing disaster is one of the most serious threats to power grid security in China. This article provides a brief glance of current China's monitoring and prevention methods of icing disaster (MPI) development status. Despite a late start, China's research and development on MPI have made outstanding achievements, including formation mechanism causing ice disaster, key technologies and characteristics, and anti/de-icing approaches development and application. It is apparent that Chinese scientists and engineers confronted the worldwide problem of anti/de-icing, and put forward a comprehensive solution, which plays a more critical role in icing disaster prevention and reduction of power grid during the past 15 years. The article states that the anti/de-icing devices have been applied successively to severe icing issues. These achievements are leading the world in the development and application of MPI. However, it is only at the extreme ice and snow conditions that can test and verify whether prevention methods are comprehensive and perfect or not. And the authors discovered the application limitations in the existing achievements. The article also discusses the overall development trends of MPI in the areas of key technological and technical breakthroughs and application scenarios etc. These discussions serve as references for MPI's future technological advancement and its ever-expanding applications.