Research On Winding Insulation Of High-voltage Motor

For realizing the policy of energy saving transmission that electric power industry putsforward. Our country supplies10kV power grid for the city to reduce line losses. And thedemand of10kV motor is increasing. With the improvement of rated voltage, the insulationperformance needs be higher. High voltage motor is used in driving all sorts of large industrialmachinery and be a prime motor. Under the process of long-term operation in severeenvironment, its insulation system prone to micro defects inducing discharge. If there is amachine halt, it will cause huge economic losses. So the insulation system of high voltagemotor requirements are more strict.The lifetime, the costs of maintenance and manufacture, will largely depend on theelectrical insulation system of high voltage(HV) motors. In particular, the stator windinginsulation is the most critical component for the reliable operation of AC motors, and one thirdof emergency shutdown is caused by the stator insulation system failure. Many statorinsulation system faults are primarily caused by the slot discharge(SD), which graduallydeteriorated groundwall insulation to failure under heat, chemical, and mechanical effect.Recently, partial discharge(PD) and vibration sparking(VS) are two major stator slot dischargeproblems. But They are fundamentally different types of discharge and VS is more aggressivethan PD. This paper first explains the principle of two different types of PD, corona dischargeand spark discharge. Then we make simulation models and analyze them. Finally optimizingthe structure of anti-corona coating to ensure the reliable operation of HV motors.First of all, choosing a high voltage motor physical model, as YKK450-610kV for anexample. Then introducing two kinds of the stator slot partial PD phenomena, coronadischarge and spark discharge. Respectively explaining their concept of discharge anddischarge process how to damage the main insulation. Then according to their respectivedischarge mechanism, mathematical and simulation models to calculate.Secondly, this paper introduces the stator slot VS phenomenon. The discharge mechanismis completely different from PD. The damage ability of VS to the main insulation is muchstronger than PD. Under different conditions building a mathematical model to calculate.Finally, according to the calculation results of two kinds of discharge, and using dichotomy shooting method for stator coil anti-corona layer structure optimization design.Then selecting the appropriate resistance and rational semiconductor materials。This study is referred to10kV high voltage motor stator winding anti-corona layerstructure design and optimization.