As one of the key equipments in a power plant

the generator circuit-breaker is necessary to go through standard type test before usage. Because of its special working condition

the test methods in standards are particular. The T100 a test is the most important test for generator circuit-breaker

and it is also one of the test items not easy to pass. At present

the manufacturers of the generator circuit-breakers in China generally perform the test according to the national standard GB/T 14824—2008 High Voltage AC Generator Circuit-breakers. The new standard IEC 62271-37-013 Alternating Current Generator Circui-breakers is going to be issued

however its T100a（asymmetric current breaking capacity） test is different from the corresponding test in the standard GB/T 14824—2008. In this paper

the T100 a test methods in both standards are compared

and conclusion is drawn that the provisions in the standard IEC 62271-37-013 are more equivalent to the actual operating conditions of the generator circuit-breaker. Moreover

on the basis of the actual condition of Xi’an High Voltage Apparatus Research Institute Co.

Ltd.

a T100 a test for a24 kV

160 kA generator circuit-breaker was conducted with the parallel generator synthetic test method following the standard IEC 62271-37-013.