Recommendation of voltage line disturbance test (.PDF Download)
It seems that everyone is testing IEC61000-4-11 in order to obtain CB certification and international certification (CE marking etc.). The IEC61000-4-11 standard specifies voltage dip, short interruptions, and voltage variation immunity tests. The class determines test level and duration. Regarding judgments, the level of performance standard required is different, depending on each standard required of EUT.
Is it enough to do this test as immunity tolerance in the actual field? Not in my experience. This is especially true if it is intended to be used in countries and regions with insufficient power infrastructure. In the worst case, the equipment will fail. So, I recommend that you test thoroughly before releasing the product to make sure that the problem does not occur.