Load and performance analysis of generator winding insulation under variable power conditions
HE Yuling
YANG Jiawen
WU Xuewei
SUN Kai
AN Jiajun
ZHU Xiaoguang
WANG Xiaodan
Abstract：[Objective]Winding insulation of wind generators suffers severe electro-thermal-mechanical degradation under fluctuating power profiles,endangering system reliability.This study systematically investigates the non-uniform load distributions and multi-property insulation evolution under variable operations.[Methods]Firstly,taking a 250 kW permanent magnet synchronous wind generator as the prototype,the electromechanical transient and three-dimensional heat transfer mathematical models were established.Secondly,high-fidelity electromagnetic-thermal-structural coupled finite element workflows were constructed via Ansys software platform to extract the spatiotemporal temperature matrices and vibration spectrums under full-power,half-power,and no-power conditions.Finally,guided by numerical boundaries,an test aging rig applying a 100 Hz sinusoidal mechanical preload(30 N for full-power,9.4 N for half-power)paired with prioritized gradient thermal units was customized to execute an accelerated electro-mechanical coupling aging process lasting 180 d.Microstructural,thermal,and dielectric characterizations were implemented to quantify the property degradation.[Results]Numerical diagnostics indicate that structural temperature fields display a highly non-uniform pattern(parabolic axially and hotter at lower layers),with the peak equivalent temperature climbing steeply at full power due to intensified copper thermal dissipation.The end-winding vibration profiles are strictly governed by even-order harmonics dominated by the 2-fold frequency component(100 Hz),where the peak amplitude scales up proportionally with output power.Empirical data verify that the accelerated aging breaks epoxy macromolecular chains;as the modeled power increases,microstructural fracturing accelerates,triggering monotonic reductions in the elastic modulus,thermal conductivity,and volume resistivity,whereas the multiplication of polar free radicals promotes the orientation polarization,thereby inducing a steady inflation in the relative dielectric constant.
Keywords：GeneratorInsulation performanceElectromagnetic vibrationTemperature riseDamage
Publication Date：2026-06-30
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：8( 70-77 )