Statistical Review of Voltage Endurance Test of Insulation for High Voltage Rotating Machines Stator Windings with Combined Standard and Accelerated Tests. “Three Steps Test” TST.

Voltage Endurance (VE) test is one of the key test to evaluate High Voltage Rotating Machines (HVRM) stator winding. There are two different practices for VE test in application to the HVRM stator winding. The first practice used most for research purposes is the VE test till the failure. This practice can be used for insulation life expectancy evaluation. The second practice for VE test is so named type test to qualify particular manufacturing product. This practice is used as a part of the quality inspection program.There are several different schedules for type VE tests however there is no agreed harmonization between the different test schedules. The most widely used industrial standard for VE type test is the standards IEEE 1553 which is proposing two options for VE test: Schedule A and Schedule B. Standard consider that VE test per Schedule B is stricter then VE test per Schedule A. Standard IEEE 1553 does not provide relations between different test schedules. Also there are no relations of VE test per IEEE 1553 with other standards or VE test practices.In this article authors are discussing the potential harmonization between the different test practices and schedules for VE tests for the HVRM stator winding. Authors are proposing to test HVRM stator winding insulation at three test values, naming the test as Three Step Test (TST). TST allows to gain two important things in the same time: the direct comparison between different test schedules and parameters for insulation life expectancy.The proposed VE TST is relatively quick. TST is basing on the significant empirical data accumulated by authors. TST allows to predict the potential outcome of the type test with a high level of confidence.