考虑海洋环境影响的DFIG定子绕组短路特征挖掘与早期故障辨识

Offshore wind power has been developed rapidly, however it still faces significant challenges, such as poor accessibility, high failure rate, difficult maintenance, etc. The stator winding is an important component of the offshore doubly-fed wind turbine (DFIG). Due to the harsh marine environment and fault tolerant characteristics of the converter, it is a tremendous challenge to detect the stator windings short-circuit fault at the early stage. This project focuses on the analysis of the coupling mechanism and decoupling problem of marine environment, the fault-tolerant characteristics of converter and the early fault features of the offshore DFIG stator windings. Based on the correlation analysis between the fault mechanism and the behavior characteristics, this project investigates the theories and methods of the feature mining and the early fault identification of the DFIG stator windings short-circuit considering the effects of marine environment. In this project, an accurate and convenient grid-connected model of DFIG windings faults is built. The coupling rules of the marine environment and the fault characteristics of DFIG stator windings fault are studied. Moreover, the new characteristics adaptable to complex offshore conditions with high sensitivity and reliability are obtained. Finally, an early fault identification method is proposed considering the fault-tolerant characteristics of offshore converters. Based on the comparison between the fault experiment and the real measurement of DFIGs at Donghai Bridge offshore wind farm, the early fault identification of the DFIG stator windings short circuit with the strong disturbances of the marine environment is realized. This project provides the scientific guidance for the safe operation of offshore wind farms. Moreover, it has important practical significance for the strategic implementation of offshore wind farm development and utilization in China.

海上风电发展势头迅猛，但面临可及性差、故障率高、维护困难等难题。定子绕组是海上双馈风力发电机（DFIG）的重要部件，受恶劣海洋环境及变流器容错特性干扰，其短路故障早期辨识面临巨大挑战。项目围绕海洋环境、变流器容错特性与海上DFIG定子绕组短路早期故障特征的耦合机理分析与解耦问题，通过故障机理与行为特征间的相关性分析，研究考虑海洋环境影响的DFIG定子绕组短路特征挖掘与早期故障辨识的理论和方法。构建精确便捷的DFIG绕组故障并网模型，研究海洋环境与DFIG定子绕组故障特征的耦合规律，挖掘适应海上复杂工况的高灵敏和高可靠的新特征，提出计及海上变流器容错特性的早期故障辨识方法。结合故障模拟实验，并与东海大桥海上DFIG实测数据对比分析，实现海洋强干扰状态下DFIG定子绕组短路早期故障辨识。项目研究为海上风电系统的安全运行提供科学指导，对我国海上风能开发与利用的海洋强国战略实施具有重要的现实意义。

海上风电开发是实现国家“3060”双碳战略的重要举措。随着我国海上风电的规模化、深远海化发展，更大的装机容量和更远的离岸距离，使得海上双馈风力发电机（DFIG）特有的可及性差、故障率高、维护困难的问题愈发突出，其早期故障辨识面临巨大挑战。.项目围绕海洋环境、变流器容错特性与海上DFIG定子绕组短路早期故障特征的耦合机理分析与解耦问题，通过故障机理与行为特征间的相关性分析，研究考虑海洋环境影响的DFIG定子绕组短路特征挖掘与早期故障辨识的理论和方法。.首先，构建了适应多平台无缝衔接的DFIG定子绕组内部短路故障模型。基于DFIG定子绕组短路早期故障特征的机理分析，提出了定子绕组在不同短路故障状态下电感参数的变化规律。通过对短路后电感参数的精确计算，构建基于多回路理论的定子绕组内部短路故障的电压方程及磁链方程，该模型可以实现定子绕组匝间、相间等不同短路故障的精确建模。在MATLAB软件中实现短路故障模型，DFIG并网变频器的控制系统仿真通过dSPACE平台实现，基于MATLAB与dSPACE平台的无缝连接，实现故障模型与实际变流器及控制系统的无缝衔接与多平台实时联动，为后续的故障辨识工作奠定了理论基础。.其次，研究了海洋环境与DFIG定子绕组故障特征的耦合规律，在早期故障特征信号原本微弱的情况下滤除海洋环境的干扰，提出了适应海上复杂工况的高灵敏和高可靠的新特征——基于电流的Park's矢量2倍频分量模和基于磁链的双侧磁链观测差，揭示了海上双馈风力发电机定子绕组匝间短路故障特征严重程度的变化规律。.最后，本项目实现了计及海上变流器容错特性的早期故障辨识。通过分析变流器有、无容错控制下对故障新特征的影响，利用对称阻抗偏移差量化预警门槛，可以在微小的差异下优化海上双馈风力发电机定子绕组的故障预警门槛。既保证了控制系统具备一定的容错特性，又具有更高的可靠性。结合定制的DFIG实物电机与半实物仿真平台，验证了本项目方法的可行性与有效性。.项目成果应用于东海大桥海上风电场，为海上风电系统的安全运行提供科学指导，对我国清洁能源战略和海洋强国战略实施具有十分重要的理论研究意义与工程实用价值。