期刊：
International Journal of Electrical Power & Energy Systems,2023年152:109223 ISSN：0142-0615
通讯作者：
Zhou, WD
作者机构：
[Tu, Yingang; Pei, Xiangyu] Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha 410114, Peoples R China.;[Liu, Yuan; Zhou, Wandi; Chen, Longlong; Gao, Chong; Zhang, Sheng] State Grid Smart Grid Res Inst Co Ltd, Beijing 102209, Peoples R China.
通讯机构：
[Zhou, WD ] S;State Grid Smart Grid Res Inst Co Ltd, Beijing 102209, Peoples R China.
关键词：
VSC-based DC grid;Hybrid DC circuit breaker;Multi-Port hybrid DC circuit breaker;Controllable active oscillation circuit
摘要：
The hybrid high voltage DC circuit breaker (HDCB) is widely regarded as the most promising solution to the fault current interruption of VSC-based DC grids. However, because of a large number of power electronic modules connected in series in transfer branch, the cost of existing HDCBs are pretty high, which limiting their large-scale commercial application. In this paper, a novel multi-port hybrid high voltage DC circuit breaker commutated by controllable active oscillation circuit (CAOC-MPHDCB) is proposed. Based on the principle of controllable active oscillation, the proposed CAOC-MPHDCB can realize the reliable commutation and fast interruption of fault current while significantly reducing the total cost and operation loss. In addition, the CAOC-MPHDCB can not only isolate line faults that occur continuously in a short time, but also maintain system ring-network structure after isolating the faulty DC bus. The influencing mechanism of parameters on the performance of CAOC-MPHDCB are analysed in detail, and the selection methods of corresponding parameters are obtained. The simulation results show that the principle of CAOC-MPHDCB is effective and feasible.
摘要：
The detection of building changes (hereafter ‘building change detection’, BCD) is a critical issue in remote sensing analysis. Accurate BCD faces challenges, such as complex scenes, radiometric differences between bi-temporal images, and a shortage of labelled samples. Traditional supervised deep learning requires abundant labelled data, which is expensive to obtain for BCD. By contrast, there is ample unlabelled remote sensing imagery available. Self-supervised learning (SSL) offers a solution, allowing learning from unlabelled data without explicit labels. Inspired by SSL, we employed the SimSiam algorithm to acquire domain-specific knowledge from remote sensing data. Then, these well-initialised weight parameters were transferred to BCD tasks, achieving optimal accuracy. A novel framework for BCD was developed using self-supervised contrastive pre-training and historical geographic information system (GIS) vector maps (HGVMs). We introduced the improved MS-ResUNet network for the extraction of buildings from new temporal satellite images, incorporating multi-scale pyramid image inputs and multi-layer attention modules. In addition, we pioneered a novel spatial analysis rule for detecting changes in building vectors in bi-temporal images. This rule enabled automatic BCD by harnessing domain knowledge from HGVMs and building upon the spatial analysis of building vectors in bi-temporal images. We applied this method to two extensive datasets in Liuzhou, China, to assess its effectiveness in both urban and suburban areas. The experimental results demonstrated that our proposed approach offers a competitive quantitative and qualitative performance, surpassing existing state-of-the-art methods. Combining HGVMs and high-resolution remote sensing imagery from the corresponding years is useful for building updates.
摘要：
近年来，清洁低碳的电-气综合能源系统（electricity-gas integrated energy system， EGIES）受到了广泛关注。然而，EGIES涉及不同能源形式的设备量测与信息传输，数据误差的产生因素复杂且不确定性突出，导致确定性的点状态估计可信度不足，为系统安全稳定运行带来严峻挑战。针对此问题，提出基于模型-数据联合驱动的EGIES区间状态估计方法。建立EGIES加权最小二乘（weighted least square， WLS）点状态估计模型，并利用人工鱼群算法（artificial fish swarms algorithm， AFSA）求解；考虑估计结果置信水平，利用核密度估计（kernel density estimation， KDE）构造点状态估计误差区间，进而得到区间状态估计结果；基于量测量样本与区间状态估计结果样本，训练长短期记忆（long short term memory， LSTM）神经网络得到EGIES快速区间状态估计模型。以30节点电力系统与14节点天然气系统耦合的EGIES进行算例分析，结果表明，所提区间状态估计方法的区间覆盖概率均保持在置信度水平之上。同时所提方法测试集在线估计时间仅为13.97s，相比于WLS-NR-KDE方法与WLS-AFSA-KDE方法分别降低76.44%与94.00%。
摘要：
In robot-assisted rehabilitation, the performance of robotic assistance is dependent on the human user’s dynamics, which are subject to uncertainties. In order to enhance the rehabilitation performance and in particular to provide a constant level of assistance, we separate the task space into two subspaces where a combined scheme of adaptive impedance control and trajectory learning is developed. Human movement speed can vary from person to person and it cannot be predefined for the robot. Therefore, in the direction of human movement, an iterative trajectory learning approach is developed to update the robot reference according to human movement and to achieve the desired interaction force between the robot and the human user. In the direction normal to the task trajectory, human’s unintentional force may deteriorate the trajectory tracking performance. Therefore, an impedance adaptation method is utilized to compensate for unknown human force and prevent the human user drifting away from the updated robot reference trajectory. The proposed scheme was tested in experiments that emulated three upper-limb rehabilitation modes: zero interaction force, assistive and resistive. Experimental results showed that the desired assistance level could be achieved, despite uncertain human dynamics.
摘要：
Abstract With the rapid development of social economy, power supply reliability of the distribution network has become particularly important. The distribution network has long been faced with problems such as overvoltage, single‐phase grounding failure and grounding protection. Passive, active, and hybrid arc suppression devices (ASDs) are proposed to solve these problems. Passive ASDs have the advantages of high reliability, low control complexity and good economic benefits, and have been widely used in distribution networks. With the wide application of power electronic components in distribution network, the active part and harmonic part of ground current, which cannot be effectively eliminated by passive ASDs, increase sharply. Therefore, an active arc suppression method is proposed. However, due to the high cost and low reliability of the active equipment, the hybrid ASD has better arc suppression effect. In this paper, the existing ASDs are reviewed, and specific simulation models are established to verify the principle and performance of three different ASDs. The advantages and disadvantages of the three ASDs are compared in detail, and the possible problems and research directions in the future research of arc suppression technology are prospected.
摘要：
O3-type layered oxides are widely investigated as cathodes for Na-ion batteries (SIBs) due to their high theoretical capacities and splendid initial Coulombic efficiency. However, they suffer from fast capacity fading owing to the complicated phase transformations, especially in high cut-off voltage (>4 V). Herein, Ti and Co elements were simultaneously introduced to O3-Na(Ni0.3Fe0.2Mn0.5)(0.85)Ti0.1Co0.05O2 (NFMTC) cathode material, and the effects of Ti/Co co-doping on phase structure and electrochemical properties were analyzed in detail. The results reveal that Ti/Co co-doping can enhance the {010} plane, interlayer space and Na-ion diffusion kinetics, resulting in the improved electrochemical performance. Therefore, the NFMTC cathode delivers a high reversible capacity of 174.7 mAh g(-1) at 0.1 C in the voltage range of 2.0-4.3 V and a good rate capability (53% of the initial capacity at 5 C) as well as an excellent capacity retention of 78% after 300 cycles at 1 C. This work maybe provides a guidance to explore high-performance cathode materials for sodium ion batteries.
摘要：
先进信息技术在智能配用电系统(Smart power distribution and utilization system,SPDUS)中的广泛应用,加深了系统信息侧与电力物理侧的耦合程度,智能配用电系统已逐渐转变为信...展开更多 先进信息技术在智能配用电系统(Smart power distribution and utilization system,SPDUS)中的广泛应用,加深了系统信息侧与电力物理侧的耦合程度,智能配用电系统已逐渐转变为信息-物理空间高度融合、信息资源与物理资源相互结合与协调的智能配用电信息物理系统(Smart power distribution and utilization cyber physical system,SPDU-CPS)。本文重点从面向SPDU-CPS的网络攻击入侵检测、网络攻击防御保护以及自愈控制三个角度,对国内外相关技术的发展与挑战进行总结、梳理。在网络攻击入侵检测方面,总结了基于偏差类、基于特征类以及混合类网络攻击检测方法的检测思路及实施路径;在网络攻击防御保护方面,总结了提升信息网络防御能力的信息侧保护方法、基于资源优化配置和数据校正保护的物理侧保护方法以及融合两侧信息及保护功能的信息物理协同保护方法;在自愈控制方面,对传统电力物理侧自愈控制以及基于信息物理协同的自愈控制现有研究进行了归纳和整理。最后,结合SPDU-CPS的特点及发展趋势,对未来研究方向进行了展望。收起
摘要：
In most industrial applications, it is difficult to obtain complete demagnetization fault signals of all conditions with labels for permanent magnet synchronous motor (PMSM), and motors are not allowed to be disassembled, so non-contact diagnostic methods are essential. A non-contact fault diagnosis method using magnetic leakage signal based on wavelet scattering convolution network (WSCN) and semi-supervised deep rule-based (SSDRB) classifier is proposed. Through magnetic equivalent circuit model analysis, the magnetic leakage signal on motor surface is selected as fault signal. To avoid complex signal processing, the symmetrized dot pattern method is introduced to convert fault signals into two-dimensional images. Then, WSCN is applied to extract features from images, and SSDRB classifier is adopted to diagnose demagnetization fault. Finally, faulty motor prototypes are manufactured for experiment. By comparing with other methods, the superiority and effectiveness of the proposed method using a small number of labeled samples under different conditions are verified.
作者：
Yu, Xiaoquan;Li, Wei;Li, Shuo;Yang, Yingze;Peng, Jun
期刊：
Sustainability,2023年15(18) ISSN：2071-1050
通讯作者：
Li, W;Li, S
作者机构：
[Yu, Xiaoquan; Li, W; Li, Wei] Cent South Univ, Sch Traff & Transportat Engn, Changsha 410075, Peoples R China.;[Yu, Xiaoquan] CRSC Res & Design Inst Grp Co Ltd, Beijing 100070, Peoples R China.;[Li, S; Li, Shuo] Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha 410114, Peoples R China.;[Peng, Jun; Yang, Yingze] Cent South Univ, Sch Comp Sci & Engn, Changsha 410083, Peoples R China.
通讯机构：
[Li, S ; Li, W ] C;Cent South Univ, Sch Traff & Transportat Engn, Changsha 410075, Peoples R China.;Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha 410114, Peoples R China.
关键词：
heavy-haul trains;cooperative control;predictive set point modulation;virtual coupling
摘要：
Virtual coupling systems are important for improving the safety and efficiency of heavy-haul trains by coordinating the velocities of heavy-haul trains. However, the set point change of reference velocity leads to unsafe train operation. To address this issue, in this paper, a cooperative reference velocity regulation control method is proposed for virtual coupling systems of heavy-haul trains, which can smoothly adjust the train velocity during the operation process. Firstly, the heavy-haul trains are characterized by a cyber-physical model, where the physical layer models the longitudinal dynamics of the trains, while the cyber layer represents the communication topology of the trains using graph theory. Secondly, a cooperative control law is designed to achieve velocity consensus and maintain a safe distance between adjacent trains. The set point modulation method is utilized to smoothly adjust the reference velocity of heavy-haul trains, suppressing velocity fluctuations of heavy-haul trains. The proposed approach is validated through extensive simulations under acceleration and deceleration conditions. Simulation results verify that the proposed method can significantly reduce the velocity fluctuations during the operation of virtual coupling systems when compared with the classical cooperative control method.
关键词：
三维激光雷达, 外参标定, RANSAC算法, 反对称矩阵, 最小二乘, 3D LiDAR, external parameter calibration, RANSAC algorithm, antisymmetric matrix, least square
摘要：
在工程应用中使用三维激光雷达的基础是对激光雷达的外参数进行标定，而对激光雷达外参标定通常都需要其他传感器的数据进行联合标定，且标定方法复杂，过程耗时较长。对此，提出一种简便的自动标定算法。首先利用RANSAC算法拟出多个平面，并通过相邻点法向量的夹角进行平面的二次筛选得到其平面方程，再根据平面方程得到平面间的交点坐标，使用反对称矩阵构建旋转矩阵，进一步利用交点坐标在雷达坐标系与世界坐标系下的不同求得近似转换关系，最后利用最小二乘思想对近似矩阵进行优化，得到较为准确的旋转位移矩阵。所提算法可以在特征点、角点点云缺失的情况下，通过平面方程拟合出较为精确的角点。仿真结果表明，该算法是可行的。 The basis of using 3D LiDAR in engineering application is to calibrate the external parameters of LiDAR, and the external parameters of LiDAR usually need to calibrate the data of other sensors jointly, and the calibration method is complicated and the process is long.In this paper, a simple automatic calibration algorithm is proposed.The algorithm first uses RANSAC algorithm to draw up a number of planes, and through the angle of the normal vector of the adjacent points for the secondary screening plane equation, then according to the plane equation to get the coordinates of the intersection point between the planes, using the antisymmetric matrix to construct the rotation matrix, further using the intersection point coordinates in the radar coordinate system and the world coordinate system under the difference, to obtain the approximate transformation relationship.Finally, the approximation matrix is optimized by the least square method, and a more accurate rotation displacement matrix is obtained.In the absence of feature points and corner clouds, the proposed algorithm can be used to fit more accurate corner points by plane equation. The simulation results show that the proposed calibration algorithm is feasible.
摘要：
The mutual shielding effect between branches is thought to be one of the reasons for reduced propagation of streamer in nanofluids. However, the mechanism of how these nanoparticles induce streamer branching in oil is not clear. In this paper, a numerical model was established based on charge carrier continuity equations and field-dependent molecular ionization theory to study the propagation and branching of streamer. The effects of isolated particle with different size, permittivity, and location on streamer branching in oil are discussed in detail. It is found that isolated particle with larger size, or greater permittivity, or closer position from streamer would cause strong enough distortion of electric field around the particle. This changes the ionization distribution during the propagation of streamer to induce a side-branch. To simulate the state of "global uniformity and local clumping" of nanoparticles in nanofluids, a multi-nanoparticle system is established. The local clumped nanoparticles play a synergistic effect on electric field distortion. The reduced electric field, the increased propagating path, and the mutual shielding effect of streamer branches are responsible for the improved breakdown voltage of nanofluids.
作者机构：
[Lu, Jiazheng; Ning, Kai; Jiang, Zhenglong] Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha 410114, Peoples R China.;[Xie, Pengkang; Tang, Zhuang; Lu, Jiazheng; Hu, Jianping; Fu, Zhiyao; Jiang, Zhenglong; Feng, Tao] State Grid Hunan Elect Co Disaster Prevent & Reduc, State Key Lab Disaster Prevent & Reduct Power Grid, Changsha 410129, Peoples R China.
通讯机构：
[Zhuang Tang] S;State Key Laboratory of Disaster Prevention & Reduction for Power Grid Transmission and Distribution Equipment, State Grid Hunan Electric Company Disaster Prevention and Reduction Center, Changsha, 410129, China
摘要：
In this study, the aging process of composite insulator silicone rubber in a mountainous region environment was studied and a lifespan prediction model was constructed. Silicone rubber samples with various exposure times were analyzed based on the microstructure, physical properties, functional groups, and chemical environment of silicon. All experimental results corresponded to three aging stages: platform stage, upturn stage, and acceleration stage. Based on linear regression method, the peak content of Si(-O)2 and shore hardness A were selected to establish the lifespan prediction model for silicone rubber. Verification of the model showed that the residual lifespan error is less than 1.5 years. This study is based on a systematic analysis of three stages of the aging process for silicone rubber in composite insulators and obtaining critical aging parameters. Furthermore, a lifespan prediction model is proposed and validated.
摘要：
In this paper, a two-dimensional axisymmetric numerical model of streamer discharge in alternative natural ester liquid and conventional naphthenic oil under a positive sub-microsecond impulse voltage is proposed. The model is based on the charge drift-diffusion approximation in a divergent electric field. Simulation shows that streamer propagation in naphthenic oil is divided into two stages: stage I with a small streamer velocity of 0-0.91 km s(-1) and stage II with a rapidly rising streamer velocity up to 213 km s(-1). In natural ester, the streamer velocity gradually slows down from 4.84 km s(-1) to 2.11 km s(-1). The electric field at the head of the streamer in natural ester ranges from 2.4 x 10(8) V m(-1) to 2.5 x 10(8) V m(-1) during propagation, which is visibly lower but more consistent than that in naphthenic oil (3.5 x 10(8) V m(-1) to 8.4 x 10(8) V m(-1)). It is revealed that the different streamer features within the two types of oil are caused by the different competition between the Laplacian electric field and space charge effect at the streamer head. For streamer propagation in naphthenic oil, stage I is dominated by the Laplacian electric field whereas stage II is dominated by the space charge effect. In natural ester, the whole streamer propagation is dominated by the Laplacian electric field. Further, it is indicated that the streamer head consists of two specific discharging regions, i.e. the front region of the streamer head which guides new space charge accumulation and the back region of streamer head which guides density reduction of accumulated space charge. The expansion of the streamer tunnel is caused by the alternating space charges in these two regions. The work in this paper provides a theoretical reference for the practical application of alternative transformer liquids.
通讯机构：
[Ma, R ] C;Changsha Univ Sci & Technol, Coll Elect & Informat Engn, Changsha, Peoples R China.
关键词：
Transmission and distribution interaction;Distributed energy resources;Random -fuzzy;Energy hub;Security domain constraints;Multi -objective optimization
摘要：
In order to deal with the static voltage stability region problem of the power system caused by the penetration of distributed energy resources, this paper presents an interactive random-fuzzy optimal power flow method for transmission-distribution network considering security region constraints. Firstly, based on the random-fuzzy theory, the output of wind power and multi-energy coupling energy hub connected to transmission-distribution network are obtained. On this basis, the security region model of transmission-distribution network is established. As the interaction and cooperation between multiple distribution networks and transmission network throughout the system are described, the global random-fuzzy model of transmission-distribution interaction is established. Then, the security domain opportunity constraints are incorporated into the multi-objective optimization model of transmission-distribution network. Finally, based on the improved IEEE30 bus transmission system and IEEE33 bus distribution system, the power flow of transmission-distribution interactive network under the proposed model is calculated. The simulation results validate the effectiveness of the proposed model and algorithm. The safe operation distance of the power grid system can be improved and the active power network loss and power generation cost can be reduced.
关键词：
State-dependent ARX model;variable feedback gain;robust model predictive control;parameter variation rate;robustness and stability
摘要：
Measurement and Control, Ahead of Print. <br/>As a generalized input-output model, the state-dependent exogenous variable autoregressive (SD-ARX) model has been intensively utilized to model complex nonlinear systems. Considering that more freedom can be provided by the state feedback control with variable feedback gain for constructing robust controllers, we propose a robust model predictive control (RMPC) algorithm with variable feedback gain on the basis of the SD-ARX model. First, the polytopic state space models (SSMs) of the system are constructed and the prediction accuracy of the SSMs is further improved by using the parameter variation rate information of the SD-ARX model. Then, an RMPC algorithm with variable feedback gain is synthesized for increasing the design freedom and enhancing the control performance. Two simulation examples, that is, the modeling and control of a continuous stirred tank reactor (CSTR) and a water tank system, are provided to demonstrate the feasibility and effectiveness of the proposed RMPC algorithm.
