Method for detecting loss-of-excitation fault of permanent magnet synchronous generator

Abstract

The invention provides a method for detecting the loss-of-excitation fault of a permanent magnet synchronous generator. The method comprises the following steps: S1, determining whether a generator loses excitation according to a first output power of the generator at a first time and a second output power of the generator at a second time; S2, if the generator loses excitation, determining the loss-of-excitation type of the generator according to the sampling value of one phase of voltage at the generator end of the generator in a third period of time; and S3, determining the loss-of-excitation degree indicator of the generator according to the loss-of-excitation type of the generator. According to the method provided by the invention, the loss of excitation of the generator can be detected and the loss-of-excitation degree can be evaluated through measurement of conventional data and simple mathematical calculation, and the operation for detecting the loss of excitation of the generator is more convenient and quicker. The method not only can determine whether a generator loses excitation, but also can accurately obtain the degree of loss of excitation of the generator. The methodis of great significance to fault diagnosis and maintenance of generators.

Description

technical field [0001] 本发明涉及故障诊断领域,更具体地,涉及一种永磁同步发电机的失磁故障检测方法。 Background technique [0002] 近年来,在全球能源危机及环境污染日益严重的背景下,发展可再生能源开始受到社会普遍关注。风能作为一种清洁的可再生能源,因为其绿色环保、蕴含量大和成本较低等自身特性,越发受到世界各国的发展和推广。而永磁同步电机因其采用永磁体结构,与电励磁结构电机相比,更适合做成风力发电环境中所要求的多极低速结构,并且其省去了电刷和滑环,提高了发电可靠性和发电效率,在风力发电领域得到大规模应用。 [0003] 永磁体是永磁同步电机的重要组成部分,永磁体材料磁性能的稳定程度,将对永磁同步电机的效率、性能和可靠性等产生直接影响。永磁同步发电机在长期实际运行中,受电枢反应、温度、机械振动和化学元素等因素影响,永磁材料可能会发生程度不同的不可逆退磁。当不可逆退磁程度较轻时,会使永磁发电机各项性能指标下降;严重时,甚至会导致永磁发电机无法使用。因此,进行永磁同步发电机的永磁体磁性能及失磁故障检测,对电机安全高效运行具有十分重要的意义。目前,主要有以下三种失磁故障的检测方法: [0004] 1、基于定子电流的失磁故障检测方法 [0005] 当永磁同步电机发生失磁故障时,在定子电流中将产生对应的故障谐波分量,谐波分量的频率的公式表达为: [0006] [0007] where f deg 为故障谐波分量频率;f e 为基波频率;p为极对数。 [0008] 基于定子电流中将产生对应的故障谐波分量,便可对定子电流信号按采样定理进行采样,利用先进的信号变换方法对定子电流谐波成分进行分析,得到其电流频谱,判定永磁体失磁故障的发生以及故障发生的严重程度。采用的信号处理方法不同,便形成了不同的检测方法,常用的检测方法主要有:希尔伯特黄HHT方法、连续小波变换CWT方法、离散小波变换方法DWT、快速傅里叶变换FFT方法。 [0009] 2、基于等效磁网络的失磁故障检测方法 [0010] 利用磁网络与电网络的相似性,求出各节点的磁位或通过单元的磁通进而求得有关参数。用等值的磁导网络来模拟永磁电机,根据磁导网络来计算或测量电动势和电磁转矩,与正常运行的电机进行对比,...

AI Technical Summary

Problems solved by technology

Although method 3 can realize the on-line monitoring of permanent magnet synchronous motor demagnetization fault, it is also affected by the observation accuracy of permanent magnet flux linkage

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