【作者】 王鹏；

【导师】 王伟；

【作者基本信息】 华北电力大学(北京) ， 高电压与绝缘技术， 2019， 硕士

【摘要】 电力变压器是电力系统的关键设备,其运行可靠性直接影响整个电力系统的安全。然而局部放电是造成变压器绝缘损坏的主要原因之一,因此,局部放电检测成为变压器绝缘机理研究与质量监控的关键项目,是状态监测、维护的重要基础。局部放电超声阵列检测法是将阵列传感器与阵列信号处理技术相结合进行局部放电超声波检测的新方法。而性能良好、结构合理的局部放电超声阵列传感器是实现有效检测的前提和关键。本论文在国家自然科学基金(51577063)“基于新型内置光纤F-P传感器变压器局部放电故障定位方法的研究”的资助下,重点开展了局部放电超声阵列传感器的指向性能和测向性能的研究,主要内容及成果如下:研究了一种局部放电超声阵列传感器的指向性能评估方法。首先设计、研制了四阵元正方形、菱形、正四面体型的非本征法布里帕罗干涉(Extrinsic Fabry-PerotInterferometric,EFPI)超声传感器阵列,以阵列指向性基本理论为基础,选取定向准确度和主波束宽度为特征参量,探究了上述三种阵列传感器的空间多角度指向性,结果表明:正方形和菱形阵列的指向性随波束偏转角的增大而变差,而正四面体型阵列对空间多角度的指向性整体优于正方形阵列和菱形阵列。研究了 EFPI传感器阵列信号的波达方向(DOA)估计原理和多信号分类算法(Multiple Signalclassification,MUSIC);然后,搭建了变压器油中局部放电检测仿真、实验模型和4通道同步数采装置测试平台,并开展了对空间多角度局部放电的测向研究。结果表明:不同传感器阵列对不同方向的信源,其测向精度和指向性的变化规律一致;且较正方形和菱形平面阵列,正四面体型EFPI光纤超声阵列传感器具有良好的空间全角度局部放电测向能力。针对实际变压器绕组结构,在平面菱形阵列传感器的基础上改进设计,研制了三种不同结构的立体菱形阵列传感器,探究了阵列的空间指向性,并通过仿真和实验进行了空间全角度的局部放电测向研究。研究结果进一步验证了局部放电超声阵列传感器性能评估方法的可行性,并得到了阵列立体形式与其空间指向性能、测向性能的内在关系,用以指导立体阵列传感器设计。更多还原

【Abstract】 Power transformer is the key equipment of power system,and its operation reliability directly affects the security of the whole power system.However,partial discharge is one of the main causes of transformer insulation damage.Therefore,partial discharge detection has become a critical project of transformer insulation mechanism research and quality control,it is and an important basis for transformer’s condition monitoring and maintenance.The ultrasonic array detection method of partial discharge(PD)is a new method which combines the array sensor and array signal processing technology(ASPT)to detect PD ultrasonic signal.Among them,the partial discharge ultrasonic array sensor with good performance and appropriate structure is the premise and key to achieve effective detection.This paper is supported by National Natural Science Foundation of China(51307060)"Research on Partial Discharge Fault Location Method Based on New Built-in Fiber F-P Sensor" emphatically to carry out the research on the pointing performance and direction-finding performance of the PD ultrasonic array sensor.The main contents are as follows:A pointing performance evaluation method for a partial discharge ultrasonic array sensor was studied.Firstly,a four-element cross-shaped array,a diamond-shaped array,and a regular tetrahedral array were developed basing on the Extrinsic Fabry-Perot Interferometric(EFPI)ultrasonic sensor.Based on the basic theory of array directivity,the directional accuracy and the main beam width were selected as the characteristic parameters.And then the spatial multi-angle directivity of the above three array sensors were explored.The results show that the directivity of the cross-shaped and diamond-shaped arrays deteriorates with the increase of the beam deflection angle,while the direct tetrahedral array has better directivity to the spatial multi-angle than the cross-shaped array and the diamond array.The DOA estimation principle and Multi-signal classification(MUSIC)of EFPI sensor array signals are studied.Then,the partial discharge detection simulation,experimental model in transformer oil and 4-channel synchronous data acquisition device test platform were built.What’s more,the direction-finding study of spatial multi-angle partial discharge was carried out.The results show that the different sensor arrays have the same change of direction-finding accuracy and directivity for the source in different directions.Compared with the cross-shaped and diamond-shaped planar arrays,the regular tetrahedral EFPI fiber-optic ultrasonic array sensor has a good space full-angle partial discharge.Direction finding capability.Compared with the cross-shaped and diamond-shaped planar array,the regular tetrahedral EFPI fiber ultrasonic array sensor has a good direction-finding capability of space full-angle’s partial discharge.Aiming at the actual transformer winding structure,three dimensional diamond array sensor with different structures was developed based on the planar diamond array sensor.Then the spatial directivity of the array was explored,and the direction-finding of space full-angle’s partial discharge by simulation and experiment is carried out to search an optimal array.The research results further validate the feasibility of the performance evaluation method of the partial discharge ultrasonic array sensor,and we obtain the intrinsic relationship between the stereoscopic form of the array and its spatial pointing performance and direction-finding performance,which is used to guide the design of the stereo array sensor.更多还原