ZHANG Jie, ZHOU Yutong, LUO Hongjian, et al. Cause analysis of Cracking of Epoxy Casing in 220 kV GIS Terminal[J]. High voltageapparatus, 2021, 57(6): 240-245.
DOI:
ZHANG Jie, ZHOU Yutong, LUO Hongjian, et al. Cause analysis of Cracking of Epoxy Casing in 220 kV GIS Terminal[J]. High voltageapparatus, 2021, 57(6): 240-245. DOI: 10.13296/j.1001-1609.hva.2021.06.032.
Cause analysis of Cracking of Epoxy Casing in 220 kV GIS Terminal
In order to analyze the reasons for the cracking of B-phase epoxy sleeve in outdoor GIS terminal of a 220 kV substation project
the failure samples and intact samples were examined by macroscopical inspection and penetration detection
and the shape and distribution of the cracks were determined. Then the tensile properties of the materials were determined by mechanical properties
expansion coefficient determination
FTIR detection
SEM
EDS and so on. Strength
coefficient of expansion
composition
micro-particle size
etc. The results show that the cracking of the casing originates from the edge of the nut hole of the insert. The curing shrinkage stress occurs in the manufacturing process of epoxy resin. Under the action of temperature difference
the additional stress caused by the superposition of the corner between the nut insert and the epoxy resin is caused by the difference of the expansion coefficient between the epoxy resin and the insert nut. The above two factors lead to the cracking of the casing. Major countries: In addition
the uneven size of micro-structure particles in epoxy resin is also a possible cause of cracking.Conclusion: The cracking of casing can be prevented by improving curing process
reducing shrinkage stress
improving epoxy resin formulation
improving structure and properties
and adopting smooth transition surface to reduce stress.