Studies based on AC high voltage tests have been done at Cepel to investigate the performance of 800 kV busbar insulators under heavy wetting conditions.Insulators were tested which are now used on site and also with ...Studies based on AC high voltage tests have been done at Cepel to investigate the performance of 800 kV busbar insulators under heavy wetting conditions.Insulators were tested which are now used on site and also with different configurations of booster sheds.Images recorded by ultra-violet(UV) camera were used to help the investigations on the effectiveness of booster sheds.By comparing UV images of the insulator being stressed with high voltage under heavy artificial rain,with and without booster sheds,it was possible to observe how significant the reduction on the flashover formation process was when booster sheds were used.The effectiveness of booster sheds was also quantified by determining the disruptive discharge of the insulator with and without them.The results of these studies can also be considered as contribution to national and international standard technical committees to improving the standardized procedure for tests on ultra high voltage(UHV) insulators under heavy rain.Subjects such as the clear definition of relevant UHV test procedure and test arrangements,including the use of UV camera,have to be taken into account.展开更多
An 800 kV electric power substation can have more than one hundred of porcelain multicone type insulators supporting busbar structures.Two or more sections in series,having middle and end fittings,compose these insula...An 800 kV electric power substation can have more than one hundred of porcelain multicone type insulators supporting busbar structures.Two or more sections in series,having middle and end fittings,compose these insulators.Ageing process can cause degradation of the cement used in this type of insulator and this fact can affect its dielectric performance under heavy rain.This paper presents results of an investigation based on power frequency high voltage tests performed on 800 kV porcelain multicone type insulators,removed from service after having operated for more than 20 years,as well a non-used one that had been stored on site for long time.The insulators were tested in different arrangements:each section at a time and the two sections assembled in series,as actually used insulator columns.The tests were carried out under artificial rain ranging from 1 mm/min to 5 mm/min.The results have confirmed a reduction of up to 30% in the insulator power frequency flashover voltage under 5 mm/min rain conditions and gave important information to the utility about radial cracks that were observed in many insulators and about the discharge mechanisms along the insulators under rain.展开更多
文摘Studies based on AC high voltage tests have been done at Cepel to investigate the performance of 800 kV busbar insulators under heavy wetting conditions.Insulators were tested which are now used on site and also with different configurations of booster sheds.Images recorded by ultra-violet(UV) camera were used to help the investigations on the effectiveness of booster sheds.By comparing UV images of the insulator being stressed with high voltage under heavy artificial rain,with and without booster sheds,it was possible to observe how significant the reduction on the flashover formation process was when booster sheds were used.The effectiveness of booster sheds was also quantified by determining the disruptive discharge of the insulator with and without them.The results of these studies can also be considered as contribution to national and international standard technical committees to improving the standardized procedure for tests on ultra high voltage(UHV) insulators under heavy rain.Subjects such as the clear definition of relevant UHV test procedure and test arrangements,including the use of UV camera,have to be taken into account.
文摘An 800 kV electric power substation can have more than one hundred of porcelain multicone type insulators supporting busbar structures.Two or more sections in series,having middle and end fittings,compose these insulators.Ageing process can cause degradation of the cement used in this type of insulator and this fact can affect its dielectric performance under heavy rain.This paper presents results of an investigation based on power frequency high voltage tests performed on 800 kV porcelain multicone type insulators,removed from service after having operated for more than 20 years,as well a non-used one that had been stored on site for long time.The insulators were tested in different arrangements:each section at a time and the two sections assembled in series,as actually used insulator columns.The tests were carried out under artificial rain ranging from 1 mm/min to 5 mm/min.The results have confirmed a reduction of up to 30% in the insulator power frequency flashover voltage under 5 mm/min rain conditions and gave important information to the utility about radial cracks that were observed in many insulators and about the discharge mechanisms along the insulators under rain.
