Effectiveness analysis of corona protection materials for HV rotating machines

• Published in: Dianji yu Kongzhi Xuebao = Electric Machines and Control Vol. 29; no. 4; p. 35
• Main Authors: Victor, Belko, Feng, Shengxi, Efrem, Feklistov, Feng, Yu, Liu, Ji
• Format: Journal Article
• Language: Chinese; English
• Published: Harbin Harbin University of Science and Technology 01.04.2025
• Subjects: Electric corona; Electric field strength; Electric fields; Heat; Heat resistant materials; Insulation; Material properties; Operating temperature; Rotating machines; Simulation models
• ISSN: 1007-449X
• DOI: 10.15938/j.emc.2025.04.004

In this paper a fully parametrized finite element simulation model of the stator bar end is created using the COMSOL Multiphysics. The model allows conducting the comparison of different corona protection structures' design, various materials properties, and finally optimizing the corona protection system. Several samples of SiC based nonlinear conductivity materials for corona protection were fabricated in laboratory and then investigated. The conductivity dependencies on electric field（0.05 to 1 kV/mm） and temperature（20 to 155 ℃） were measured. By comparing the heat-resistant grades of the corona protection material and the insulating material, the maximum working temperature of the corona protection material corresponds to the heat-resistant grade F of the insulating material. As the temperature increases, the nonlinear characteristics of the corona protection material in the experiment decrease dramatically, reducing the heat-resistant grade of the corona protection material. The decrease in the nonlinear characteristics of the corona protection material at the maximum operating temperature causes the maximum electric field strength at the end of the HV rotating machines end corona protection（ECP）exceeding the corona discharge electric field strength, resulting in corona phenomenon.