Research on Inter-turn Short-circuit Fault Diagnosis Method Based on High Frequency Voltage Residual for PMSM

Inter-turn fault is a serious stator winding short-circuit fault of permanent magnet synchronous machine(PMSM). Once it occurs, it produces a huge short-circuit current that poses a great risk to the safe operation of PMSM. Thus, an inter-turn short-circuit fault(ITSCF) diagnosis method based on high frequency(HF) voltage residual is proposed in this paper with proper HF signal injection. First, the analytical models of PMSM after the ITSCF are deduced. Based on the model, the voltage residual at low frequency(LF) and HF can be obtained. It is revealed that the HF voltage residual has a stronger ITSCF detection capability compared to the LF voltage residual. To obtain optimal fault signature, a 3-phase symmetrical HF voltage is injected into the machine drive system, and the HF voltage residuals are extracted. The fault indicator is defined as the standard deviation of the 3-phase HF voltage residuals. The effectiveness of the proposed ITSCF diagnosis method is verified by experiments on a triple 3-phase PMSM. It is worth noting that no extra hardware equipment is required to implement the proposed method.

Analysis on the fault characteristics of three-phase short-circuit for half-wavelength AC transmission lines

Half-wavelength AC transmission(HWACT) is an ultra-long distance AC transmission technology, whose electrical distance is close to half-wavelength at the system power frequency. It is very important for the construction and operation of HWACT to analyze its fault features and corresponding protection technology. In this paper, the steady-state voltage and current characteristics of the bus bar and fault point and the steady-state overvoltage distribution along the line will be analyzed when a three-phase symmetrical short-circuit fault occurs on an HWACT line. On this basis, the threephase fault characteristics for longer transmission lines are also studied.

Short-circuit fault analysis and isolation strategy for matrix converters

The behavior of matrix converter(MC) drive systems under the condition of MC short-circuit faults is comprehensively investigated. Two isolation strategies using semiconductors and high speed fuses(HSFs) for MC short-circuit faults are examined and their performances are compared. The behavior of MC drive systems during the fuse action time under different operating conditions is explored. The feasibility of fault-tolerant operation during the fuse action time is also studied. The basic selection laws for the HSFs and the requirements for the passive components of the MC drive system from the point view of short-circuit faults are also discussed. Simulation results are used to demonstrate the feasibility of the proposed isolation strategies.

Remedial Phase-Angle Control of a Five-Phase Fault-Tolerant Permanent- Magnet Vernier Machine With Short-Circuit Fault

A fault-tolerant permanent-magnet vernier(FT-PMV)machine incorporates the merits of high fault-tolerant capability and high torque density.In this paper,a remedial phase-angle control(RPAC)strategy is proposed for a five-phase FT-PMV machine with short-circuit fault.Firstly,the proposed strategy can reduce the amount of unknown quantities by structuring the phase-angles of the normal phases.It can simplify the calculation of the remedial currents.Then,in order to obtain the desired torque,only the amplitudes of the remedial currents need to be calculated.Based on the principle of instantaneous electrical input power and mechanical output power balance condition,the real components are used to maintain the torque capability,while the reactive components are limited zero to minimize the torque ripple.Both simulations and experiments are presented to verify the proposed RPAC strategy.

New “Intellectual Networks” (Smart Grid) for Detecting Electrical Equipment Faults, Defects and Weaknesses

The most important elements of “intellectual networks” (Smart Grid) are the systems of monitoring the parameters of electrical equipment. Information-measuring systems (IMS), which described in this paper, were proposed to use together with rapid digital protection against short-circuit regimes in transformer windings. This paper presents an application’s experience of LVI-testing, some results of the use of Frequency Response Analysis (FRA) to check the condition of transformer windings and infra-red control results of electrical equipment. The LVI method and short-circuit inductive reactance measurements are sensitive for detecting such faults as radial, axial winding deformations, a twisting of low-voltage or regulating winding, a losing of winding’s pressing and others.

Intelligent System Design for Stator Windings Faults Diagnosis:Suitable for Maintenance Work

The short circuit is a severe fault that occurs in the stator windings. Therefore, it is very important to diagnose this type of failure in its beginning before it causes unscheduled stop and the machine loss. In this context, the Support Vector Machine (SVM) is a tool of considerable importance for standard classification. From some training data, it can diagnose whether or not there is a short circuit beginning, and which is important for predictive maintenance. This work proposes a technique for early detection of a short circuit between the turns aiming at its implementation in a real plant. The paper shows simulation and experimental results, and validates the proposed technique.

永磁同步电机故障诊断方法研究综述

永磁同步电机(permanent magnet synchronous motor,PMSM)具有结构简单、运行稳定、效率高和外形多样等显著优点,在生产制造领域得到广泛应用。PMSM在工作中不断受到速度变化和负载波动等复杂工况的影响,不可避免地会出现各种故障,如轴承故障、偏心故障、退磁故障和匝间短路故障等。文中综述了PMSM常见故障类型,并总结了自动化领域中基于信号的状态监测方法的现有研究,以用于各类电气和机械故障的检测和诊断。随后,对诊断方法进行了总结,并分析了其优势与限制,探讨了不同信号处理方法在应用中的利弊。最后,根据当前研究现状,讨论了PMSM故障监测与诊断存在的问题和未来发展方向。

基于开口变压器法的交流电机定子非激励相绕组匝间短路检测研究

为了解决交流电机定子绕组中线圈绝缘损伤引起匝间短路故障无法准确、快速定位的问题,提出将检测转子绕组匝间短路的开口变压器法移植到检测交流电机定子绕组匝间短路,定子单相添加激励源,非激励相绕组设置故障点,开口变压器检测故障点所在槽,分析故障前后开口变压器绕组感应电动势的变化。首先阐述开口变压器检测定子非激励相的工作原理,分析正常和故障状态下通过开口变压器铁心漏磁通的表达式,进一步得到开口变压器绕组感应电动势表达式,获取故障变化规律。随后建立交流电机电磁仿真模型,进行仿真分析,最后用一台定子样机进行实验验证。结果表明:故障状态下,随着故障程度的加深,故障点所在槽的开口变压器感应电动势随之减小,证明了开口变压器可以作为离线检测交流电机定子非激励相绕组匝间短路故障的有效手段。

基于二维CNN与多源机电信息融合的同步电机转子匝间短路故障诊断方法

为提高同步电机转子绕组匝间短路故障的诊断准确率,以一台型号为SDF-9的一对极同步发电机为研究对象,提出了一种基于二维卷积神经网络(Convolutional Neural Networks, CNN)与多源机电信息融合的匝间短路故障诊断方法。首先选取故障前后的定子环流、转子振动、定子振动信号为故障特征,采用信号-图像转换方法将一维时序信号转化为二维灰度图像。其次将处理后的图像分别作为二维CNN模型的前置输入进行训练。最后采用D-S证据理论将3种证据体的输出概率进行决策融合。结果表明:该方法消除了单一信号易受传感器故障及环境变化的影响,故障诊断准确率显著提高,并与其他传统故障诊断算法的诊断结果进行对比分析,验证了此方法的有效性。

干式空心并联电抗器绕组匝间绝缘故障特征分析

本文通过有限元软件建立仿真分析模型,研究干式空心并联电抗器绕组匝间绝缘故障的物理特征,探寻便于故障监测的敏感状态量。首先在有限元仿真软件中建立基于实际电抗器的“场-路”耦合模型并验证正确性,之后在其绕组不同层、不同高度位置设置匝间绝缘故障,研究回路总电流、等效阻抗、有功功率损耗等电气特征量随故障位置的变化规律,并分析空间磁感应强度和绕组受力的变化情况。结果表明:所研究的电气特征量变化率随绕组单匝匝间短路位置的变化而变化,在径向上呈现从内层到外层增大的趋势,在最外层有所减小,在轴向上由绕组中部向端部逐渐减小。绕组单匝匝间短路状态下的空间磁感应强度和故障绕组受力明显增大,等效电阻、功率因数和有功功率损耗的变化率均在500%以上,变化显著且方便获取,可作为干式空心并联电抗器匝间绝缘故障的在线监测量。

船舶发电机定子绕组匝间短路故障预警

为保障船舶的安全航行,需要对船舶发电机定子绕组早期匝间短路故障进行预警。首先,通过同步发电机的数学模型对正常运行和不同程度的匝间短路故障进行仿真,选取负序电流分量和电磁转矩作为故障特征量并进行信息融合;然后,使用CNN-BiLSTM网络对特征量进行回归预测得到网络预测的残差;最后,根据残差的变化趋势和设定的阈值来判断故障的发展情况。结果表明,建立的模型可以实现定子绕组匝间短路故障的预警,并且基于自适应原理设置的动态阈值会比固定阈值提前确认故障。

改进2D-CNN的永磁同步电机故障诊断分析

针对卷积神经网络在噪声环境中特征提取能力不足,导致永磁同步电机故障诊断出现准确率低、泛化能力差的问题,提出了一种改进二维卷积神经网络与混合注意力机制的故障诊断方法。该方法首先将采集的一维时序信号转换为二维灰度图;其次,改进多尺度特征提取模块,将该模块部分普通卷积替换为空洞卷积,以最大程度地提取到数据信号中的有效信息;然后引入混合注意力机制动态更新权重参数,强化故障特征,抑制噪声的干扰;最后使用分类器进行匝间短路故障诊断。实验结果表明:与其他方法相比,文中模型具有更好的准确性和鲁棒性;在各噪声背景下,本模型的准确率均在96%以上,表明所提方法具有较强的抗噪性能和泛化能力。

电机定子匝间短路故障诊断系统研究

电机定子匝间短路故障是电机运行中常见的一种故障形式,是指电机线圈中相邻导线间因绝缘损坏而产生的电气短路。文章研究电机定子匝间短路故障诊断系统,通过引入先进的信号处理技术、数据驱动的故障诊断模型、特征提取与优化策略及故障定位与定量分析技术,提高故障检测的准确性和效率。实验结果表明,该故障诊断系统在实际应用中表现良好,能够为电机维护提供可靠、高效的技术支持。

核能发电机转子线圈匝间短路在线监测分析系统研究与应用

转子匝间短路是发电机常见的一种缺陷,严重的匝间短路故障会影响机组的安全稳定运行,对运行中的发电机转子匝间短路状况进行在线监测具有重要意义。本文介绍了基于探测线圈波形法的核能发电机转子匝间短路在线监测系统的信号检测原理、实现方法及应用情况。该系统引入键相信号用于定位匝间短路故障位置和提高匝间短路故障诊断的准确性,具有重要实用价值,也为实施发电机状态监测和状态检修奠定技术基础。

Design and Optimization of Dual-Winding Fault-Tolerant Permanent Magnet Motor

To improve the performance of the traditional fault-tolerant permanent magnet(PM)motor,the design and optimal schemes of dual-winding fault-tolerant permanent magnet motor(DWFT-PMM)are proposed and investigated.In order to obtain small cogging torque ripple and inhibiting the short-circuit current,the air gap surface shape of the PM and the anti short-circuits reactance parameters are designed and optimized.According to the actual design requirements of an aircraft electrical actuation system,the parameters,finite element analysis and experimental verification of the DWFT-PMM after optimal design are presented.The research results show that the optimized DWFT-PMM owns the merits of strong magnetic isolation,physics isolation,inhibiting the short circuit current,small cogging torque ripple and high fault tolerance.

Placement optimization of Multi-Type fault current limiters based on genetic algorithm

The fault current limiter(FCL)is an effective measure for improving system stability and suppressing short-circuit fault current.Because of space and economic costs,the optimum placement of FCLs is vital in industrial applications.In this study,two objectives with the same dimensional measurement unit,namely,the total capital investment cost of FCLs and circuit breaker loss related to short-circuit currents,are considered.The circuit breaker loss model is developed based on the attenuation rule of the circuit breaker service life.The circuit breaker loss is used to quantify the current-limiting effect to avoid the problem of weight selection in a multi-objective problem.The IEEE 10-generator 39-bus system in New England is used to evaluate the performance of the proposed genetic algorithm(GA)method.Comparative and sensitivity analyses are performed.The results of the optimized plan are validated through simulations,indicating the significant potential of the GA for such optimization.

Single-phase earth fault current distribution between optical fiber composite overhead ground wire and ordinary ground wire in transmission system

It is important for the safety of transmission system to accurately calculate single-phase earth fault current distribution.Features of double sided elimination method were illustrated.Quantitative calculation of single-phase earth fault current distribution and case verification were accomplished by using the loop method.Influences of some factors,such as single-phase earth fault location and ground resistance of poles,on short-circuit current distribution were discussed.Results show that:1) results of the loop method conform to those of double sided elimination method;2) the fault location hardly influences macro-distribution of short-circuit current.However,current near fault location is evidently influenced;and 3) the short-circuit current distribution is not so sensitive to the ground resistance of poles.

轴裂相整数槽集中绕组永磁容错电机及其匝间短路故障抑制研究

针对传统分数槽集中绕组永磁容错电机相间隔离能力弱、匝间短路故障抑制能力不足的问题,该文提出一种轴裂相整数槽集中绕组永磁容错电机。该电机各相绕组沿轴向独立排布,实现了相间的电、磁、热及物理隔离。首先,介绍轴裂相整数槽集中绕组电机的基本结构,阐述其工作原理,分析其电磁性能。然后,理论分析该轴裂相整数槽集中绕组永磁电机匝间短路故障的抑制机理。在考虑绝缘接触电阻变化的基础上,将所提轴裂相整数槽集中绕组永磁电机与传统分数槽集中绕组永磁电机在不同接触电阻情况下的故障电流、损耗和温升进行对比和分析。研究表明,相比于传统分数槽集中绕组永磁容错电机,该文所提轴裂相整数槽集中绕组永磁容错电机在故障的各个阶段,其匝间短路故障的严重性均较低,并且故障对健康相的影响很小,实现了从电机结构上抑制和隔离匝间短路故障的目的。最后,加工一台轴裂相整数槽集中绕组永磁电机样机,完成对样机匝间短路电流和故障温升的测试,实验结果与理论分析和仿真结果一致,证明了上述分析的正确性。

Validation of Full-Converter Wind Power Plant Generic Model Based on Actual Fault Ride-Through Measurements

Modeling and validation of full power converter wind turbine models with field measurement data are rarely reported in papers. In this paper an aggregated generic dynamic model of the wind farm consisting of full power converter wind turbines is composed and the model validation based on actual field measurements is performed. The paper is based on the measurements obtained from the real short circuit test applied to connection point of observed wind farm. The presented approach for validating the composed model and fault ride-through （FRT） capability for the whole wind park is unique in overall practice and its significance and importance is described and analyzed.

基于多目标优化的永磁同步电机容错控制研究

电机定子绕组匝间短路是最常见的一类故障形式,若不进行处理会逐渐发展为相间或相对地短路,从而导致电机损坏。为了保障电机的安全运行与故障下转矩输出质量,需要及时对故障电机进行有效的容错控制。首先,以永磁同步电机为研究对象,通过电机定子绕组匝间短路故障等效电路获得电机数学模型,并分析了d-q轴电流平面下的故障电机转矩、短路环流及绕组温升。然后,为实现对故障电机电流的准确预测,对电机定子绕组匝间短路故障等效电路进行合理电路变换,建立故障电机预测模型,进而提出了一种多目标优化预测容错控制策略。最后,搭建电机实验平台,对提出的容错控制策略进行实验验证,结果表明:该方法可有效抑制短路环流及绕组温升并降低故障电机的转矩脉动。