海上风电机组变流器失效分析及防护策略

Failure Analysis and Protection Strategy of Converters of Offshore Wind Turbine

变流器作为整个海上风电机组核心部件之一,一旦出现故障问题会给风电机组运行带来极大安全隐患,机组运行环境条件与变流器的可靠性密切相关。对故障变流器控制器进行故障点进行定位,再做进一步的研究和剖析,结合运行环境检测结果,找出具体的失效原因,针对风电机组变流器电气件失效的问题,采用扫描电镜(SEM)、能谱仪(EDS)等微观及组织表征手段,利用电化学还原测试分析方法对运行环境腐蚀严酷度进行表征,分析风电机组电气件失效机理及原因,同时提出科学的防护策略指导风电运维。风电机组变流器控制器出现失效现象的原因是变流器运行环境空气中存在H2S腐蚀性气体,且腐蚀等级均在G3等级以上。变流器控制器失效的主要原因是控制器面板上的贴片电阻2次硅胶保护层边界不整齐,与面电极(Ag)交界处存在孔隙或缝隙,导致H2S气体分子从边界处的微孔或缝隙中侵入与面电极接触生成大量的Ag2S,随着体积膨胀,Ag2S切断面电极,从而使电阻的阻值变大,直至开路,导致控制器失效引发变流器故障。提出了通过直接将微型过滤装置安装于变流器机柜内来实现变流器内电气件环境空气优化的主动防护策略。

As one of the core components of the whole offshore wind turbine,the converter will bring great security risks to the operation of the wind turbine once it fails.The operating environment conditions are closely related to the reliability of the converter.The fault point of the fault converter controller is located,and then the further research and analysis are done,combined with the results of the operating environment detection,to find out the specific failure causes.Aiming at the failure of electrical components of wind turbine converters,this paper adopts microscopic and tissue characterization means such as scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS),and uses electrochemical reduction test and analysis method to characterize the corrosion severity of operating environment,analyzes the failure mechanism and causes of electrical components of wind turbines,and puts forward scientific protection strategies to guide wind power operation and maintenance.The reason for the failure of the converter controller of wind turbine is that there is H2S corrosive gas in the air of the converter operating environment,and the corrosion level is above G3 level.The main reason for the failure of the converter is that the boundary of the secondary silicone protective layer of the patch resistance on the controller panel is irregular,and there are pores or gaps at the junction of the surface electrode(Ag),it is lead that H2S gas molecules invade the surface electrode from the microhole or gap at the boundary and contact with the surface electrode to generate a large number of Ag2S.With the volume expansion of Ag2S,the surface electrode is cut off,thus increasing the resistance value of the resistor until the circuit is open,resulting in the controller failure and the converter fault.an active protection strategy to optimize the ambient air of the electrical components in the converter by directly installing the micro filter in the converter cabinet is present.