Study On The Detection Of The Wetting Degree Of Polluted Insulator Based On Phase Angle Difference

The wetting degree of pollution insulators have an important influence on the insulation safety of transmission line,while there have no specific measuring methods and corresponding indicators on the wetting degree of pollution insulators at present.In order to explore the effective detection parameters of the wetting degree of pollution insulators,this paper analyzes the wetting process and its influence factors of pollution insulators.The advantages and disadvantages of the commonly detection methods are discussed.In this paper,a new method of detecting the wetting degree of pollution insulators by measuring the Phase Angle Difference(PAD)between the pollution voltage and current is proposed.Then the wetting tests on the typical transmission line insulators in the artificial climate chamber by using a self-made detection device have been carried out.The relationship between the changes of PAD and the wetting time and the relationship between the surface conductivity and the wetting degree of pollution insulators have been studied.The results show that the changes of PAD curve can effectively characterize the entire wetting process of the pollution layer from the initial stage,through the saturated stage to the oversaturated and washing away stages.Furthermore,in the artificial climate chamber,the influence of the steam flowing rates,pollution composition,pollution degree and insulator structure on the wetting characteristics of the polluted insulators have been studied.Test results show that the steam flowing rates mainly affecting the wetting velocity.The composition of the contaminant has a significant influence on the saturated wetting time and saturated wetting surface conductivity.Pollution degree has a great influence saturated wetting surface conductivity.Under the same conditions,the insulators with simple structure,self-cleaning performance have a shorter wetting time and better wetting uniformity.because of the barrier of lower surface arris and other parts,the wetting speeds of LXHY5-70 insulator are significant differences in each parts.The hydrophilic porcelain(glass)insulator is easier to be wetted than the hydrophobic composite insulators.At last,the AC flashover characteristics of typical LXAY-70 transmission line insulators under different wetting states have been studied in the artificial climate chamber.The results show that wetting states have a direct influence on the flashover voltages of the pollution insulator;and the PAD of the surface contamination layer can effectivity characterize the change of the insulation state of the insulator during the wetting process.The experimental results can offer an important guidance for artificial pollution test.