Development and Validation of Reliability Testing Methods for Insulation Systems in High-Voltage Rotating Electrical Machinery on Ships

Abstract

Lloyd’s Register became the first classification society to mandate reliability testing for insulation degradation in rotating electrical machinery. As the maritime industry shifts toward eco-friendly practices, high-voltage rotating electrical machinery on ships increasingly features higher voltages and larger capacities. However, incidents involving insulation systems have also become more frequent. Additionally, testing facilities with the necessary equipment to perform such reliability tests are lacking, and standardized testing methods are yet to be established. This study proposes test items, methods, and evaluation criteria for the reliability testing of high-voltage rotating electrical machinery. The testing methods are broadly categorized into four types: thermal, electrical, multifactor, and thermomechanical degradation reliability testing. The proposed methods were validated by conducting long-term testing over approximately one year. Key results showed a breakdown time of 7056 h in thermal evaluation, 5040 h in electrical evaluation, and 258.5 d in multifactor evaluation, as well as a 63rd percentile value of 245.7 h in thermomechanical evaluation, all of which fulfill the required criteria. The study offers practical guidelines for ensuring the durability and safety of high-voltage electrical machinery, aligning with the sustainability and safety goals of the maritime industry.