定子主绝缘受潮频域介电参量提取及状态评估

针对吸收比等传统电气参数测试结果分散性大、易受外界干扰等问题,提出将频域介电谱技术引入发电机定子主绝缘受潮状态评估过程.对不同老化状态的定子主绝缘样品进行受潮试验,得到不同状态样品的吸收比和介质损耗频域谱.结合灰色关联法,深入分析测试结果,划分四种绝缘受潮状态和四个特征频段,通过特征频段的介损积分值构建标准状态向量组,...

Extraction of dielectric parameters and status evaluation of stator main insulation in frequency domain

Aiming at the test results that traditional electrical parameters such as absorption ratio are highly dispersed and susceptible to external interference.The frequency domain dielectric spectroscopy technology was introduced into the evaluation process of the damp state of the generator stator main insulation.Moisture test was performed on insulation samples in different aging states to obtain the absorption ratio and dielectric loss frequency domain spectrum of samples in different states.Combined with the grey correlation method,and the test results were analyzed,and four kinds of insulation moisture state and four characteristic frequency bands were divided,a standard state vector group was constructed through the dielectric loss integral value of the characteristic frequency band,and the insulation moisture state was qualitatively evaluated.According to monotonic increase of dielectric loss integral with frequency,the maximum dielectric loss integral of the test frequency band was defined as the moisture evaluation factor.A connection with the absorption ratio was established,quantitatively assessed the insulation moisture state.The frequency-temperature shift factor was introduced to correct the dielectric loss curve at different test temperatures,and the activation energy was calculated to verify feasibility of this method.The laboratory sample verification provides a new idea for application of frequency domain dielectric spectroscopy in the evaluation of epoxy-mica composite insulation.