Research On Characteristics And Detection Technology Of Contact Overheating Defects Of GIS Equipment Isolation Switch

As the main equipment in the power system,GIS operates stably and reliably,but due t o equipment assembly,structural materials,manufacturing processes and other reasons,the st ability of GIS equipment is difficult to be guaranteed.When the contacts of the GIS disconnec t switch are overheated,it will accelerate the reduction of the insulation performance,whic h may easily lead to accidents such as short circuit and seriously endanger the power syste m.Commonly used contacts of GIS equipment include plum blossom contacts,spring contact s,strap contacts,etc.,and there are various methods of detecting GIS equipment contacts.Ba sed on a variety of GIS equipment contacts,the temperature rise characteristics of plum bloss om contact fingers under normal and abnormal installation conditions of GIS disconnectors ar e studied,and by monitoring the temperature rise and characteristic gas,it is helpful to underst and the temperature of plum blossom contact fingers in GIS disconnectors in time Rise or con tact state,and prevent the occurrence of overheating failure of GIS disconnectors.Aiming at the problem of overheat failure of the missing spring part of the torch contact f inger of the GIS disconnector,the temperature rise test of the torch contact finger of the disco nnector and the characteristic gas analysis test of the evolution process of the local overheatin g defect of the GIS equipment were carried out.The experiment investigated the positioning p roblem of the temperature rise sensitive points of the housing of the GIS equipment disconnec tor under different contact conditions when the plum blossom fingers,conductive rods,and sh ielding cover heat,and the temperature between the components of the disconnector and the te mperature rise sensitive points of the housing was obtained.Rise relationship,the relationshi p between temperature and current,and the relationship between transient temperature and ste ady-state temperature with time.And the results of the critical temperature,the relationship b etween the characteristic gas content and the temperature of the characteristic gas during the o verheating evolution of the GIS equipment disconnector,and the change of the characteristi c gas content with time under the condition of constant critical temperature was obtained.According to the linear relationship between the upper contact finger,the lower contact fi nger,the conductive rod of the GIS equipment isolation switch,and the shielding case and the temperature rise sensitive point of the housing,it can be inferred by monitoring the temperatu re rise sensitive point of the housing whether the GIS equipment disconnector has overheated fault;the change law of the characteristic gas content with time under constant temperature co ndition and the relationship between the characteristic gas content and temperature provide the criterion for the overheating fault diagnosis of the GIS equipment disconnect switch.Based on the above research conclusions,the online monitoring method based on fiber Bragg grating temperature measurement technology and the temperature rise monitoring method of GIS equ ipment isolating switch based on infrared temperature measurement technology are improved and perfected,and have been promoted to practical applications.