Performance of Non-Linear Stress-Grading Systems at Non-Sinusoidal Voltages

In this paper, the performance of nonlinear stress-grading systems of high voltage rotating machines under to non-sinusoidal voltages is studied. A lumped circuit model of stress-grading system applied to high voltage stator windings is developed. The model generates the time variation as well as the effective value of the surface electric field and potential distribution along with the power dissipation of the stress-grading system. The performance characteristics of the stress-grading systems are generated under different impulse voltage waveforms with various standard rise times. Impulse waveforms with very short rise time, cause the most concentration of the electric stress and cause the most power loss in the stress-grading system.