Research On Condition Assessment And Maintenance Strategy Of GIS Equipment Based On Multidimensional Fuzzy Theory Model

Gas Insulated Combination Equipment(GIS)is a very important kind of equipment in substations.How can you quickly diagnose the actual operating conditions of GIS equipment based on the actual situation of the intelligent substation project site,identify potential risk points of GIS equipment in operation and timely Eliminating hidden dangers and avoiding all kinds of risks caused by overhaul or other unnecessary repairs are the key topics of China's State Grid Corporation of China.First,the paper introduces the basic internal structure and main functions of GIS equipment,and then analyzes the main internal faults of GIS equipment.The internal faults of GIS equipment are mainly divided into discharge faults(spark discharge,partial corona discharge,and arc discharge)and thermal faults.In addition,the degradation mechanism inside GIS equipment under the effect of discharge fault and thermal fault,especially the decomposition of sulfur hexafluoride gas and other chemical reactions inside it,are discussed further,which lays the foundation for GIS equipment condition monitoring and fault diagnosis.Secondly,based on the actual needs of the project site,based on scientific principles,measurability principles,and comprehensive coverage principles,this paper establishes GIS equipment tools including toxic gas indicators,electrical indicators,insulation degradation indicators,and mechanical characteristics indicators.Status assessment system and further refinement of different indicators: further refinement of toxic gas indicators into sulfur tetrafluoride,carbon monoxide,sulfur difluoride,nitrogen monoxide,hydrofluoric acid,sulfurous acid,sulfur pentafluoride,etc.The electrical indicators are further refined into two indicators: the bus voltage and the approved load of the GIS equipment;the insulation deterioration indicators are further refined into three indicators: water vapor content index,furan content index,and insulation medium degradation index;The mechanical characteristics of GIS equipment are further refined into four indicators,such as circuit breaker closingand opening time,circuit breaker opening and closing synchronization time,and the average annual number of circuit breaker openings,providing a basis for the study of the status evaluation of GIS equipment.Then,the paper establishes a GIS equipment condition assessment model based on fuzzy analytic hierarchy process,using online monitoring data,combining condition assessment factors and mechanical characteristic data obtained from case inspections,to finally achieve the status scoring of the complete set of GIS equipment.Because the main element of each state evaluation contains more than one sub-item factor,and under different operating conditions,each factor has different effects on the complete GIS equipment.Therefore,each state evaluation factor and its sub-items need to be weighted separately,so that the most accurate evaluation of the operating conditions of the complete GIS equipment can be achieved.First,all operating conditions of the complete GIS equipment are divided into four different types:normal,attention,abnormal,and severe.After that,different element factors are firstly equalized and the initial weights of different secondary indicators are determined.Then,a weight adjustment strategy model based on fuzzy theory is established according to the actual situation.Finally,the gray correlation method is used to determine the finality of different indicators under different working conditions.Weights,so as to solve the problem of quantitative evaluation of complete GIS equipment,and provide a basis for the condition maintenance of GIS equipment.Finally,based on the research method in this paper,the same type of 220 kV complete GIS equipment(ZF34-220(L))in four different intelligent substations,including A,B,C,and D in Quanzhou,Fujian Province,was used./ Y4000-50)Based on the operation and fault data,a comprehensive analysis and evaluation of the operating conditions were conducted,and the scientificity and engineering practicability of the paper were verified from different perspectives.