大型潜水电机复杂气隙偏心的基础理论及实验研究

Large electrical motors are widely used in national security prevention and control of water. And yet, the air-gap eccentricity has a strong impact on the operational reliability. To seek effective air-gap eccentricity diagnostic techniques is an important approach of dealing with air-gap eccentricity in large electrical motors. The project focuses on the basic theoretical and experimental research of complex air-gap eccentricity in large submersible motors. The main research contents are as follows: 1) The complex air-gap eccentricity models are established by applying rotor dynamics theory, including the influence of number of poles and slots, stator winding type, stator and rotor slot type, gravity, bearings, unbalanced magnetic pull, etc; 2) The singularity of the 3-dimensional space magnetic field distribution is quantitatively analyzed using analytical and finite element method. The characteristics of the magnetic field under eccentricity conditions are collected, and the mapping relations of these characteristics and the degree of eccentricity are investigated; 3) Multi-position magnetic field measurement strategy is proposed based on the above complex air-gap eccentricity theory. To confirm the validity of the theoretical analysis, a prototype with reconstructive bearing system is employed in the experimental research. The research of the project will change the domestic situation which the air-gap eccentricity of large submersible motors could not be detected precisely. It meets the pressing needs of national security prevention and control of water as well as air-gap eccentricity diagnostic techniques of large electrical machines. The project is of great practical value and has a profound theoretical significance on the perfection of large electrical machine fault diagnosis technology and a series of research related to machine air-gap eccentricity.

大型潜水电机广泛应用于国家安全防治水需求场合，但气隙偏心问题严重影响其运行可靠性。寻求有效的气隙偏心诊断技术是解决大型电机气隙偏心故障的重要途径。本项目以大型潜水电机为研究对象，开展复杂气隙偏心的基础理论及实验研究。主要研究内容包括：1)运用转子动力学的相关理论，建立在极槽数、定子绕组形式、定转子槽型、重力、轴承、不平衡磁拉力等因素影响下的复杂气隙偏心模型；2)采用解析法和有限元法定量研究复杂气隙偏心状态下三维空间磁场分布奇异性，提取有效的偏心磁场特征量，探索其与偏心度之间的映射关系；3)基于上述复杂气隙偏心理论，提出多点磁场测量策略，对具有改造轴承系统的样机进行偏心实验研究。本项目的研究将改变我国大型潜水电机气隙偏心无法精确诊断的局面，满足国家安全防治水、大型电机气隙偏心诊断等技术迫切的科技需求。对大型电机故障诊断技术的完善以及与电机气隙偏心相关的一系列研究具有深远的理论意义和实用价值。

随着大电机技术的快速发展，汽轮机等大型旋转电机作为重要的能源动力装备，在国民经济中发挥着越来越重要的作用。与此同时，为提高大型电机装备的可靠性和降低系统故障，大型旋转电机运行状态监测与故障诊断技术，近年来也受到电机领域学者的高度重视。气隙偏心故障作为大型旋转电机中非常普遍的故障，一直以来都是国内外相关领域专家学者研究的热点问题之一。该项目以大型潜水感应电机为研究对象，在深入分析气隙偏心数学模型的基础上，提出了一种基于弧偏心模型的气隙偏心研究方法，详细分析了弧偏心情况下电机的参数、运行特征，并且给出了一种可以识别弧偏心的基于磁场检测线圈的气隙偏心综合检测方案。项目研究成果主要包括以下几个方面：.1. 通过分析偏心转子的旋转特性，从计算和检测两个角度建立了气隙弧偏心较为完整的数学模型，并且针对干式潜水电机转子温升较高的特点考虑了铁心热膨胀对气隙偏心的影响；.2. 分别应用绕组函数理论和磁路理论分析计算了弧偏心情况下的电感和不平衡磁拉力特征，并与轴向均匀的动态偏心情况下的特征进行了对比；.3. 采用有限元的方法分析了感应电机偏心情况下的磁场特征，结合单点磁场测量策略和多点磁场测量策略提出了一种基于磁场检测线圈的电机复杂气隙偏心检测方法及其实现方式。