As large-scale, high-proportion, and efficient distribution transformers surge into the grids, anti-short circuit capability testing of transformer windings in efficient distribution seems necessary and prominent. To deeply explore the influence of progressively short-circuit shock impulses on the core winding deformation of efficient power transformers, a finite element theoretical model was built by referring to a three-phase three-winding 3D wound core transformer with a model of S20-MRL-400/10-NX2. The distributions of internal equivalent force and total deformation of the 3D wound core transformer along different paths under progressively short-circuit shock impulses varying from 60% to 120% were investigated. Results show that the equivalent stress and total deformation change rate reach their maximum as the short-circuit current increases from 60% to 80%, and the maximum and average variation rate for the equivalent stress reach 177.75% and 177.43%, while the maximum and average variation rate for the total deformation corresponds to 178.30% and 177.45%, respectively. Meanwhile, the maximum equivalent stress and maximum total deformation reach 29.81 MPa and 38.70 μm, respectively, as the applied short-circuit current increased to 120%. In light of the above observations, the optimization and deployment of wireless sensor nodes was suggested. Therefore, a distributed monitoring system was developed for acquiring the vibration status of the windings in a 3D wound core transformer, which is a beneficial supplement to the traditional short-circuit reactance detection methods for an efficient grid access spot-check of distribution transformers.

大容量试验是检验电力装备性能,保障装备安全可靠运行的重要环节.现有的大容量试验回路主要依靠人工操作,存在流程复杂、效率低且易出错的问题.针对大容量试验回路智能化控制的难题,研究建立了冲击发电机单电机短路模型和双电机并联短路模型,分析了发电机短路特性,结合典型大容量试验回路设计了一键顺控方案,提出试验回路一键顺控操作流程.通过对发电机短路模型和大容量试验回路系统的仿真,验证了所建发电机短路模型的正确性及大容量短路试验一键顺控方案的合理性.

In recent years, the traditional ICP algorithm has high requirements for the initial position of point clouds, and low registration ability for point clouds with low overlap. The Microsoft Kinect depth sensor was used to obtain the point cloud data of the target object from the real scene. Then, pre-processing such as point cloud segmentation, filtering and down sampling. In the coarse registration, the feature point sampling consistency algorithm was used to make the point cloud obtain a better initial position. Finally, a point-to-surface ICP algorithm optimized by linear least squares was proposed in the fine registration. The experimental results show that the root mean square error of the improved algorithm is 0.761mm and the time is 52.32ms. Compared with the ICP algorithm based on SIFT feature points and the improved ICP algorithm based on feature point sampling consistency, the registration accuracy of the improved algorithm is increased by 21.0% and 43.3%, and the speed is increased by 18.9% and 30.2%.

针对目前开关设备温升试验方法效率低的问题,通过分析电流幅值和频率与开关设备温升的关系,提出开关设备快速温升试验方法.首先通过对历史试验样本进行统计分析,得到对应开关设备的快速温升限值.接着,对开关设备施加大于额定幅值、频率的试验电流,直至温升达到快速温升限值.最后,将试验电流恢复至额定值,直至温升达到稳定值.试验结果表明,同时增大电流幅值和频率,可缩短开关设备温升试验时间达21.31％,所提快速温升试验方法能够可靠提高开关设备的温升试验效率.

As a well-known support, computer vision is a powerful factor to improve the application and development of the electronic system. Whether the power system can operate safely and stably can greatly influence the deduction of providence. All types of electric swinging devices are easily disturbed by various factors during the assistance operation. The ubiquitous power system that operates everywhere becomes extremely small once the electrical equipment is abandoned. For the current complexity system, if the old-fashioned hand-written visual monitoring system is still used, not only will their ability fails to meet the requirements but also the number of cumbersome, important, and financial context will be unsatisfactory. It is natural to reason about some problems. Serious problems are due to incompetent human investigation. Issues are not optimally handled during this period. The application of Coach Ken technology can fully utilize machine vision technology to analyze the salient data and identify dominant devices that support shape vision. Meanwhile, it can truly realize the supervision system of perception and machine control. In view of this, we in this work mainly expound the artifact recognition technology supported by machine vision reproduction. Besides, we disassemble the composition method of the electric power supply recognition system supported by machine vision parallel, in order to enhance the future work.

通过对低压综合配电箱(JP柜)的质量抽检,发现其温升试验不合格率较高,一旦温升超过限值将影响设备安全稳定运行.对不同供应商的JP柜开展了温升试验,比较了JP柜空间布局、塑壳断路器型号、母排结构尺寸等方面差异,分析了JP柜中塑壳断路器的温升超标原因,对JP柜中塑壳断路器选用及结构优化等方面提出了相关建议.

With the development of distribution Internet of things, the workload of judging and maintaining running state of sensors is quite considerable after large-scale construction of sensing layer. Moreover, promotion of long-distance low-power sensors puts forward the requirements of low energy consumption and bandwidth reduction for communication network between “side” and “end”. This paper proposes a state fusion evaluation method of multi-source sensors and data fusion compression method of low-power wireless sensors under the new inspection mode of distribution Internet of things. Taking the sensor system in Jiangsu power distribution substation as an example, the validity of state fusion evaluation of sensors is verified. The application of fusion compression algorithm can keep waveform characteristics and reduce data flow by 99.3%, which is more suitable for low-power and long-distance wireless transmission.

In view of the current low power consumption and low storage characteristics of sensors in the perception layer of power distribution Internet of Things, this paper analyzes the information security features and risks of the perception layer. Combined with the different security requirements of various business data of the power distribution network, it provides a suitable lightweight security protection method for various types of business of the power distribution Internet of Things.

Abstract With the rapid development of information communication, the Internet of Things and other technologies, the distribution network has evolved from a single power network to intelligent information integration. Due to the characteristics of large-scale distribution network equipment, scattered deployment, and complicated operating environment, the operation and maintenance work has problems such as low working efficiency and severely insufficient measurement coverage. Based on this, this paper adopts the system architecture of cloud, pipe, edge, and end to design an intelligent inspection system for partial discharge of power distribution equipment. The system is mainly based on intelligent sensing and supplemented by mobile detection. It integrates advanced technologies such as intelligent sensing, big data analysis, wireless communication into all aspects of distribution network inspection, so as to realize intelligent sensing, data fusion analysis and fault alarms of distribution network, guide defect elimination work in time, and provides technical support for status maintenance and safe operation of distribution network equipment.

为了更好地指导复合材料横担的应用,对矩形管聚氨酯复合材料横担及其材料样品的电气性能进行了研究.结果 表明:在绝缘子挂点距离相同且与相同规格的绝缘子组合时,矩形管复合材料横担的干燥雷电闪络电压、潮湿工频闪络电压比角钢横担分别提高了约50％和39.9％,相应的潮湿工频耐受电压和污秽耐受电压比角钢横担分别提高了约117％和30％,且潮湿闪络和污秽闪络仅发生在复合材料横担表面.

The fiber reinforced polymers (FRP) are increasingly used in poles and crossarms with good insulating and mechanical properties. In this paper, the aging resistance characteristics of various materials with different processing methods were investigated in this paper, including FRP composite poles and crossarms, the modified polyurethane (PU) resin samples bars and PU resin /glass fiber composite samples bars under the multiple environment. The multi-factor aging experimental chamber is used to simulate the long-term complex operating environment. The fiber bragg grating (FBG) strain sensors were implanted to monitor the strain of poles and crossarms in real time. The results show that after 5000h multi-factor accelerated aging test, the retention bending modulus of PU and PU composite materials samples were higher than 90%; especially for the samples under pultrusion process, its flexural modulus was up to 95.8%. The performance of aging resistance of FRP composites made by pultrusion process is optimal. The strain values at the maximum displacement of crossarm and pole are less than 2%(after 5000h. The strain value of crossarm is slightly greater than that of pole. Overall, the FRP composite poles and crossarms are of good anti-aging performance.

Adding nanoparticles to traditional transformer oil can improve their heat exchange properties as well as enhance their dielectric withstand characteristics. Investigations into the charge-carrier transport characteristics of these transformer oil-based nanofluids (TNFs) can explain their improved insulating characteristics, and clarify the mechanisms dictating these modifications. In this study, we measured the conduction current and velocity field of TNFs under high electric field excitation for the first time, for analysis of charge-carrier transport. We describe different transport processes according to the magnitude of the applied electric field, characterized as ohmic, tunneling, and space charge limited current (SCLC) stages. In the ohmic stage, characterized by very low electric field strengths, the increase in conduction current is due to the increase in the number of carriers from the addition of nanoparticles. In the tunneling stage (medium-to-high electric field strengths), the predominant charge carriers in the TNF change from ions and colloidal particles, to electrons emitted from the electrode. The thickness of the Schottky barrier at the metal-liquid interface increases on the addition of nanoparticles, which reduces the number of electrons that pass through to the interface region. The field strength required for electron transmission is enhanced, and the insulation strength is improved. In the SCLC stage (very high electric fields), the carrier mobility is reduced because of the larger trap density of TNFs and the electrical discharge is suppressed.

Dielectric loss quantifies inherent dissipation of the transformer oil-based nanofluids (NFs), which determines the operating loss and aging rate of the insulation system. Our experiment on zinc-oxide/silica NFs shows that the dielectric dissipation factor (DF) increases linearly with increasing nanoparticle volumetric concentration ranging from 0.02 to 0.25 vol.% and exponentially with increasing temperature ranging from 20 to 90 degrees C. These tendencies are well explained and estimated by a model proposed based on the conduction loss and nanoparticle relaxation polarization loss. It suggests that the conduction loss is significantly larger than the relaxation polarization loss in the NFs, whereas the dielectric loss is predominantly determined by the conduction loss. The additional shift of the charge carriers caused by the high oil temperature and the aggregation of the nanoparticles on account of the high concentration of the nanoparticles influence the actual DF of transformer oil-based nanofluids.

The oil-based nanofluids with greater dielectric strength have attracted much attention as a crucial insulating materials in high-voltage oil-immersed power equipment. In fact, the different microstructures of the transformer oil-based nanofluids (TNFs) would result in different dielectric properties. In this work, the broadband dielectric spectroscopy measurement was used to establish the linkage between the electric double layer (EDL) and dielectric response properties of TNFs which was performed at 298K temperature and with frequency range from 10-2Hz∼106Hz. The modified Havriliak-Negami (HN) model function was used to analyze the measured results. The results demonstrate that both the real and imaginary parts of dielectric spectra of two kinds of oil are composed of the conductivity and polarization process. Compared with pure oil, two polarization process could be observed for the TNFs, explained by the EDL structure reasonably. The introduction of the EDL structure provides an idea to account for the insulating strength improvement of TNFs for the first time.

At present,the global energy system and the ecological environment are facing great challenges.Under the background of the Energy Internet,both transportation system and energy utilization are developing towards electrification and greening.The coordinated development of electric vehicles and renewable energy under the smart grid is of great significance to the protection of energy security,the prevention and control of air pollution,and the promotion of energy conservation and emission reduction.However,as renewable energy has the characteristics of randomness,intermittency and electric power electronics,the coordinated development of electric vehicles and renewable energy is full of challenges.In this paper,first of all,the architecture of smart grid and the interaction between electric vehicles and renewable energy in the power grid is depicted.Following an analysis of the development of EVs and renewable energy on the power grid,the key technologies including smart charging,coordinated scheduling and energy management are investigated.Furthermore,the economic and environmental impacts of the synergies are analyzed and calculated.

In order to explore the relationship between microstructure and macroscopic performance of transformer oil-based nanofluids,we prepared nano-modified transformer oil with silicon dioxide nanoparticles and measured its stability.Moreover,we measured the dielectric spectroscopy of pure oil and oil-based nanofluids and investigated the influence of nanoparticle concentration on the frequency domain spectroscopy of nano-modified oil.The results indicate that,compared with pure oil,two obvious polarization peaks can be observed in the imaginary part of the complex permittivity of oil-based nanofluids in the measured frequency domain of oil-based nanofluids,and the value of low frequency polarization peak is higher than the high frequency one.No obvious polarization peak is presented in the whole measured frequency range.As the nanoparticle concentration increases,both the values of two polarization peaks increase,and the low frequency polarization peak has the tendency of moving to the high frequency.The Schwarz'electrical double layer theory is used to explain this phenomenon.

首先分析了变压器油的主要组成成分,构建了纯变压器油及纳米改性变压器油分子模型,随后利用分子动力学的方法得出均方根位移与时间的关系,并基于爱因斯坦关系式计算得到纯变压器油及添加Al 2 O 3 、SiO 2 、ZnO 3种纳米颗粒的纳米改性变压器油的黏度随温度的变化。结果表明:纯变压器油和纳米改性变压器油的黏度均随温度的升高呈指数下降的趋势,利用Arrhenius模型拟合发现其符合黏温特性曲线。此外,相比于纯变压器油,纳米改性变压器油的黏度有所提高,但在变压器工作温度为70~80℃时,二者差异较小。最后,通过与实验结果对比,验证了利用分子动力学方法研究纳米改性变压器油黏度的可靠性。

The DC conduction of transformer oil and transformer oil-based nanofluids were investigated with increasing electric field strength in this paper. The results show that entire process of conduction can be divided into three stages, including resistance stage, tunneling stage and space-charge limited stage. Further analysis indicate that the generation and movement mechanism of carriers are different at these three stages. At low electric field stage, the addition of nanoparticles increases the density of carriers. At medium electric field stage, the thickness of the potential barrier is increased after adding nanoparticles and electrons are captured by nanoparticles. At high electric field stage, the electrons produced by ionization are constantly being caught and released by shallow traps.

电力变压器是电力系统中的关键设备,其正常运行对保证电能输送可靠性及安全性至关重要。为了确保变压器设备处于良好状态,设备投入运行后预防性试验,在线监测及带电检测等定期巡检与维护是十分必要的,但对变压器而言,设备状态评估与故障诊断需要依据标准、规程及现场大量经验才能开展。文中依据设备运行负荷情况提出了变压器设备绝缘状态进行分析与预测方法,即通过异常值提取及数据简化建立两种典型负荷增长趋势,并利用时间序列模型对设备负荷特性进行分析对负荷增长类型进行识别。实例分析表明,文中所提出的负荷时间序列模型可运用于设备运行状态的趋势分析,且利用负荷特性分析为设备绝缘状态分析预警提供了新的思路。