Based on the experimental phenomenon that the breakdown position of the CuCr contact head in a vacuum circuit breaker may be the Cu–Cr phase boundary, the Cu–Cr interfacial binding models have been developed. The work function, work of interfacial separation, interfacial energy, charge transfer, and charge density distribution of Cu, Cr and W, Fe, Ni and Mo doped Cu/Cr interfaces are calculated from the first principles. The CuCr interface junction was found to have a smaller work function than pure copper and pure chromium. The reduced work function is prone to field emission, thus increasing the possibility of electrical breakdown. Three interfacial binding models Cu(110)/Cr(110), Cu(111)/Cr(111) and Cu(110)/Cr(100) are established in this paper. By comparing the separation work and interfacial energy, it is found that Cu(111)/Cr(111) is relatively stable. The charge transfer is ordered as W > Mo > Ni > Fe from large to small. This order is roughly the same as the atomic numbers of the four metals. The doping of W, Fe, Ni and Mo to make their work function reach the expected value is ranked as W > Ni > Fe > Mo. In this paper, we provide a theoretical basis for increasing the voltage strength of vacuum circuit breakers.

The monitor is connected in series to the earth terminal of the metal oxide arrester and is used to record the number of actions of the arrester as well as the leakage current. JB/T 10492–2011 and GB/T 24845–2018 specify the operating current of the monitor at the standard 8/20 µs waveform, while no requirements are made for other impulse current waveforms. In actual system operation, the current waveform flowing through the arrester is not always the standard 8/20 µs lightning current waveform, which may lead to the situation that the arrester monitor does not operate. In this paper, for the fault case that a DC arrester monitor at the converter station pole bus does not operate, the experimental work was carried out to analyse the causes. The results show that the longer the current waveform and the slower the wavehead, the larger the operating current of the arrester monitor. It is further inferred that in this fault case, the wider (approx. 6.5 ms) duration of the current waveform resulted in a larger current amplitude than that at 8/20 µs test waveform to trigger the monitor operation, and this operating current is likely to be greater than 700 A.

随着±800 kV陕北—湖北直流输电工程建设,受端武汉换流站岗上湾接地极周边交流变压器受到直流偏磁的影响严重,产生了振动噪声加剧等一系列问题,影响电网的安全稳定.本文针对存在严重直流偏磁的220 kV永阳变电站,结合±800 kV陕湖工程直流偏磁测试,开展了变压器实际运行工况下的声级现场试验,研究了直流偏磁电流对变压器噪声的影响,比较了变压器不同部位的噪声差异.得到了变压器噪声随直流偏磁电流的非线性增加的规律,且变压器短轴侧有载调压机构箱右上方在直流偏磁影响下的噪声变化最严重.该试验结果为变压器实际运行工况下的直流偏磁噪声诊断和特性研究提供数据支撑.

The insulator cleaning robot is essential to grid maintenance and personal safety, where the precise positioning of insulator sheds is the basis. However, due to the great differences in shape and color of the insulator, as well as the cluttered background in the substation, the traditional methods based on color and texture features can not achieve accurate positioning of the insulator shed. Aiming at the problem that the traditional features of insulator are easily submerged in the background, we propose a new depth horizontal histogram (DHH) feature and use it to achieve the accurate and fast positioning of insulator shed. In order to reduce the influence of complex background on insulator positioning, we directly bandpass filter the depth image of the insulator from the RGB-D (RGB and Depth) camera. To obtain the effective DHH feature, the filtered image is processed by rotation, horizontal projection, and morphology. Finally, we perform gradient detection on the DHH and achieve the precise positioning of the insulator sheds. The experiments show that, compared with traditional methods, our method can achieve precise positioning of the insulator shed and performs better in speed, accuracy, and adaptability.

To complete the wiring operation of the main transmission line stripped of its insulating skin in a live power distribution system, a structured-light binocular vision method is utilized to identify and locate the line. First, aiming at the interference of the background information, a depth threshold segmentation method is used to filter the background area. Second, a mean filtering method is proposed to filter out the mismatch noise of a binocular vision camera in an outdoor environment. The Canny algorithm is then utilized to extract the contour, the central axis of the main transmission line is fitted, and the difference in the neighborhood pixel value is used to recognize the stripping area. Finally, the spatial equation and attitude of the central axis of the fitting transmission line are obtained along with the central coordinates of the stripping area, guiding the robot to carry out the wiring.

变压器中性点直流偏磁电流的准确测量是开展电网直流偏磁监测、防御和治理的重要理论基础.针对变压器中性点多扁钢入地条件下,传统的扁钢采样电阻直流偏磁电流测量方法存在的问题,在不增加电流源的前提下,采用多扁钢等电阻同时采样的测量回路,提出了一种可准确测量多根扁钢流经直流偏磁电流的方法,分析了该方法中多扁钢采样阻值偏差对测量准确度的影响,并通过真形扁钢试验,验证了该方法的可行性.该方法可用于直流偏磁电流的在线监测和带电检测,具有较好的实用推广价值.

随着电力需求越来越大,电网结构越来越复杂,为保障电网负荷波动时的电能质量,并联电容器组作为常用无功补偿装置,投切频率越来越高,然而中、低压电网目前常采用真空断路器进行投切,容易出现合闸涌流及操作过电压等现象,严重影响电网安全稳定运行.以相控断路器的工作原理出发,阐述了相控开关抑制合闸涌流和过电压的优势,并以省内某变电站相控断路器改造为背景,通过现场试验验证,证明了相控开关能有效抑制涌流及过电压,可以避免因此对设备造成的危害,能够满足电网对安全、稳定、经济运行的要求.

对某变电站252 kV GIS盆式绝缘子发生大面积开裂事件进行原因分析,对开裂盆式绝缘子开展包括X射线检测、低温循环实验、绝缘材质性能实验等在内的多项技术检测手段,验证盆式绝缘子开裂原因,根据检测实验结果提出预防盆式绝缘子开裂合理化建议.

Abstract The DC de-icer installation has been widely used in the ice protection of power system. Because of the difference between the design and the actual operation of the installation, the resonance overvoltage has been threatening the device body from the distribution parameters of the de-icer transmissions. In this paper, based on the analysis on the mechanism of the resonance overvoltage, the estimate expression of the resonant length of the transmission has been derived. Through the simulation modeling by PSCAD/EMTDC, the effectiveness of the estimate expression has been verified. The suppression measures of the resonance overvoltage have been proposed.

发热缺陷是造成高压开关柜故障的主要原因之一,严重威胁主变近区安全,开关柜触头测温在线监测系统随之广泛应用于高压开关柜中.由于现行测温传感器检测方法未考虑传感器实际安装方式的影响,文中设计研制了一台高压开关柜触头测温传感器性能检测平台.该平台基于恒湿恒温箱和恒温发热平台两个主体,综合考虑了多种传感器安装方式和取电方式.应用该平台对4种类型的传感器进行了性能检测,试验结果表明:非接触式的红外辐射型传感器在实际安装方式下具有较好的测量精度,测量准确度均小于±2℃;接触式的传感器受结构形式和安装方式的影响较大,建议增加接触点数量,提高测量准确度.该平台的研制与应用对开关柜温度在线传感器相关技术规范的制定提供了试验依据.

为满足对1100 kV特高压气体绝缘金属封闭开关设备(gas insulated switchgear,GIS)的绝缘试验装置越来越高的要求,解决传统散装式试验装置效率低、自动化程度低、配合需求量大问题,提出了一种一体化的特高压绝缘试验平台的设计方案.首先介绍了试验平台的机械与电器部分的功能及其实现方式,提出了SF6电抗器内部集成电容分压屏的设计方案,再通过仿真对场强集中之处的部件与电容分压屏的设计给出了优化建议.设计与仿真结果表明,该试验平台可满足1100 kV特高压GIS设备的绝缘试验与电压测量的要求,且具有占地面积小、使用方便快捷、可减少人力与配合需求的优势,为未来特高压绝缘试验设备提供了新设计方案.

针对特高压空心电抗器在大电流工况运行时常见的电抗器内部局部温升过高的问题,文中以某1100 kV特高压油浸式空心电抗器为研究对象,在20℃的环境温度下构建了电抗器电磁场—流场—温度场二维轴对称计算模型.在模型中,对内部绝缘油的对流换热过程采用流热耦合方法,对外部空气与电抗器外壁以及电抗器底部与大地间的热交换过程;通过对附加相应的对流换热系数进行描述,从而计算出电抗器内部热点分布及绝缘油流速分布情况.结果表明,绝缘油的不充分流动是造成局部过热的原因.通过降低绝缘油粘度和拓宽顶层油道的措施,可有效改善温度分布情况.

特高压输电技术的广泛应用已经为中国能源调配、大气污染治理、大规模新能源并网接入发挥了巨大作用,±1 100 kV昌吉—古泉特高压直流输电工程是目前世界上电压等级最高、输送容量最大、输送距离最远的输电工程。文中以该工程送端昌吉换流站HD换流变现场阀侧交流外施耐压及局放试验为研究对象,通过分析试验方法、试验布置、试验设备、试验参数、电场环境校核和试验结果,验证了采用免吊装的整装式试验平台在阀厅内开展该试验的可行性,提出了阀厅内开展该试验的电场校核空气最小净距应不小于7.5 m,该次试验的最终测得局放量小于150 pC,这也是全世界首次在阀厅内开展特高压换流变的该项试验,试验的方法和结果为阀厅内开展相关试验提供了解决方案。

In order to solve the problem that the traditional metal grading ring in the ultra-high voltage(UHV) field test is so large, heavy and difficult to install in the test field that reduce the test efficiency and increase workload, a design of new inflatable grading ring especially for integrated test platform was proposed. The material and mechanical structure of the inflatable grading ring are designed according to the environment requirements of the field test. Then the style and size of the grading ring are optimized by finite element analysis of electric field. The factory test and field test are carried out and proved that the proposed inflatable grading ring is easy to use, transport, store, and meets the requirements of field test of UHV equipment within 1200kV, which can be promoted to the future UHV field test.

AC withstand voltage test on site is an important means to test the insulation performance of UHV equipment. The traditional decentralized test devices cannot meet the requirements of installation progress of UHV GIS equipment. In view of this situation, an integrated test platform for the field test of UHV equipment has been developed successfully. In this paper, the key parameters of the transmission mechanism for erecting and transporting such as the hydraulic cylinder hinge point and the thrust are calculated with analytic method. The selection method of the hydraulic cylinder is explained. The analysis method and results in this paper provide a theoretical basis for the development and selection of similar equipment.

The UHV transmission technology has played a huge role in China's energy allocation, air pollution control, large-scale new energy grid access. In this paper, a self-supporting test platform suitable for UHV GIS field insulation test has been developed. The lifting of the test site was avoided. The test preparation time is reduced from 2-3 days to 4 hours. An internal structure of 1200kV integrated oil-immersed air core reactor suitable for UHV GIS field insulation test is proposed. Through mechanical analysis and calculation, the insulated support members have been optimized in the axial and radial directions. Based on the temperature field simulation, the internal temperature distribution has been improved through widening the oil channel. The top temperature of the reactor is reduced to below 60 °C. The platform has been expansion used in the valve side AC withstand voltage and partial discharge test for UHV converter transformer. The test process fully reflects the maneuverability and integration advantages of this platform. The development of this platform provides an important implementation example for the development of the field test equipment for UHV electrical equipment.

局部放电往往是很多影响机制综合作用的结果,为了探索这些机制的单独作用,需要设置一些能够区分不同机制的放电形式,为此提出利用悬浮针模拟颗粒放电现象进行研究的方法.首先固定悬浮金属针和非金属针与主电极的不同位置,模拟颗粒畸变电场和颗粒阻碍放电通道的影响;然后和运动金属颗粒的电信号相位进行比较并进行机理分析.试验及分析结果表明:诸多机制的综合作用将会使得放电电流出现在电压上升沿和电压峰值附近;非金属颗粒虽然在起晕电压方面的影响不如金属颗粒那么大,但会通过积累的壁电荷影响放电电流的相位;自由运动颗粒的局部放电实际上受颗粒位置控制,呈现以局部击穿为主的放电现象.总之,悬浮颗粒不同机制的综合作用将导致最终的放电形式是电晕、局部击穿和介质阻挡放电分别或共同存在.

在现场进行交流耐压试验是检验特高压一次设备绝缘性能的重要手段.传统散装式试验设备已无法满足特高压GIS设备安装进度的要求.针对这一现状,研发出一种用于特高压一次设备现场试验的整装试验平台.文中运用解析法对该装置传动机构的液压缸推力、转弯半径、底盘轴荷以及转向阻力矩等关键参数对装置进行了分析计算;对装置的动力学特性进行了校核,验证了该装置在现场应用的可行性.文中的分析方法和结果为类似装备的研发和选型提供了理论依据.

提出一种可识别接触状态的隔离开关分合位置判别方法,通过对隔离开关触头压紧弹簧压力和触头温度的综合判别来实现,根据压力的突变量大小来判别隔离开关处于分位还是合位,当判断隔离开关处于合位时,根据温度的高低来判断触头接触状态是否良好.该方法简单可靠,实时性好,解决了现有隔离开关分合位置判别方法不能判别隔离开关处于半合状态的难题,对于电网设备的安全稳定运行具有重要意义.

针对智能运检技术未形成统一标准,存在技术过于超前无法落地应用,或技术过于落后效果欠佳的问题,在深入分析当前运检技术的基础上,提出了适合于当前工业发展水平的智能运检模式,并解决了其中的几个核心问题,形成了成熟的解决方案.实际应用效果表明:所提出的智能运检方案能有效提升设备状态掌控水平,大幅提高现有劳动生产率.