A new concept for online surge testing for the detection of winding insulation deterioration

A breakdown of the electrical insulation system causes catastrophic failure of the electrical machine and brings large process downtime losses. Preventive maintenance and online monitoring are some of the methods to improve reliability and reduce unscheduled downtime. One of the main reasons for failure is the breakdown of the stator insulation. The offline surge test is the most commonly used offline test to assess the condition of the turn insulation. There is no online monitoring method that is applicable to low voltage machines and has the same capabilities as the surge test. This paper introduces new concepts to implement an online surge test. The possibilities and limitations of the online surge test are presented as well as simulation and experimental results to validate the concepts.