GB/T 39891-2021 "Electrical durability test method for circuit breakers of 52kV and above" standard specifies the specific method of electrical durability test for circuit breakers of 52kV and above, including test general principles, test sample requirements, standard type test procedures, no-load test, abrasion test and acceptance test. This standard applies to E2 class SF6 circuit breakers, covering the procedures of independent and combined type tests, ensuring the long-term Reliability and safety of circuit breakers under high voltage conditions. Through standardized test procedures and conditions, the standard provides a scientific basis for the performance verification of circuit breakers.