作者机构：
[Linbin Teng; Xiaodong Xu; Chunhua Yang; Biao Luo] School of Automation, Central South University, Changsha, 410083, Hunan, China;[Yuan Yuan] School of Electrical & Information Engineering, Changsha University of Science and Technology, Changsha, 410114, Hunan, China;[Stevan Dubljevic] Department of Chemical and Materials Engineering, University of Alberta, Edmonton, T6G 2R3, Alberta, Canada;[Tingwen Huang] Department of Sciences, Texas A&M University at Qatar, Edmonton, Doha 23874, Qatar
通讯机构：
[Xiaodong Xu] S;School of Automation, Central South University, Changsha, 410083, Hunan, China
摘要：
This paper proposes a novel concurrent learning-based adaptive boundary observer designed to tackle the joint estimation problem of system states and unknown parameters for a class of hyperbolic partial differential equation systems under the circumstance of unsatisfied persistent excitation conditions. By leveraging concurrent learning technique, an adapted data points selection algorithm is employed concurrently with current data to construct the adaptation law of unknown parameters, which overcomes the limitations imposed by persistent excitation conditions and ensures exponential convergence of estimation errors of unknown parameters under finite excitation conditions. Furthermore, combining the ideas of backstepping and swapping filters on the basis of uncertain estimation, a concurrent learning-based adaptive boundary observer is designed, accompanied by rigorous theoretical analysis and proofs to demonstrate its capability of achieving exponential convergence in estimation. Finally, the corresponding illustrative simulations are given to show the effectiveness of the proposed methodology.
摘要：
Hyperspectral images (HSIs) have been widely used for target detection due to their abundant spatial and spectral information. In this article, a shadow-insensitive hyperspectral target detection (HTD) framework based on exposure fusion is proposed, which consists of the following major steps. First, the input HSI is divided into two parts, namely the shadow region and the nonshadow region. Second, total variation-based feature extraction and overexposure operation are performed on the input image to produce two feature images, i.e., the original feature image and the overexposure image. Third, a self-guided constrained energy minimization (SGCEM) detector is performed on the two feature images to detect the targets in shadow and nonshadow regions, respectively. Finally, the detection results obtained on the original feature image and the overexposure image are fused to acquire the final detection result. Extensive experiments conducted on real-world data illustrate that the proposed method can achieve satisfactory results when shadow exists.
摘要：
The paper develops an adaptive constrained tracking control technique for a class of 2 × 2 hyperbolic partial differential equation (PDE) systems with boundary actuator dynamics, which are described by a set of ordinary differential equations (ODEs) in the presence of unknown parametric nonlinearities. Since the control input only appears in the uncertain ODE subsystem rather than directly on the boundary of PDE subsystem, the control task becomes quite difficult and the existing direct boundary control approaches are ineffective. Moreover, in this paper, a more challenging problem is considered such that the controlled output and the states of ODE actuators are constrained. To this end, by utilizing finite and infinite dimensional backstepping techniques, barrier Lyapunov functions (BLFs) and adaptive methods, a novel adaptive tracking control approach is proposed. It is the first time that such a constrained tracking control problem is addressed for the PDE-ODE coupled systems considered in this paper. On the basis of the presented method, the rigorous theoretical proof is provided to show that the PDE controlled output and all the states of the ODE actuator stay within the predefined compact sets. Finally, the results are illustrated via a comparative numerical simulation.
通讯机构：
[Fan, SS ] C;Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha 100024, Hunan, Peoples R China.
关键词：
Histograms;Lighting;Visualization;Substations;Reflectivity;Inspection;Image color analysis;Global and local enhancement;histogram equalization (HE);infrared thermal image quality improvement;Retinex;substation equipment
摘要：
Noncontact infrared detection is an effective way to diagnose substation equipment defects, but inclement weather conditions like haze and rainstorms produce low-quality infrared images, making it challenging to recognize equipment. To overcome this problem, a global and local contrast adaptive enhancement method is suggested. The global approach consists of the gray-level stretching Retinex (GLS Retinex) and the weighted truncated Gaussian histogram equalization (WTGHE). The GLS Retinex comprises gray-level stretching, fast-guide filtering, and parameter self-adjustment Retinex, which can be used to brighten dark images. The WTGHE contains Gaussian histogram calculation, truncated histogram equalization (HE), and weighted RGB fusion, aiming to handle blurred images. To significantly improve the quality of images in some detailed regions that cannot be handled by global enhancement algorithms, a local scheme called regional growth reenhancement is proposed, which includes multiseed region automatic selection and adaptive threshold growth criterion. The performance of the proposed technique is evaluated using over 1000 infrared thermal photographs of several substations under extremely difficult circumstances. The experimental results show that the novel strategy outperformed existing enhancement methods. The deep-learning detector also demonstrated the effectiveness of our proposed enhancement method for the improvement of detection precision.
摘要：
Magnetosonic (MS) waves play a significant role in magnetospheric dynamics. They usually appear as electromagnetic fluctuations near the multiples of proton gyro-frequency. Recently, a distinct type of MS wave, quasi-electrostatic magnetosonic (QEMS) wave has been reported, of which only the electric field can be detected. Here we investigate the favorable generation conditions, spatial distribution, and frequency spectral features of the waves through a statistical study using Van Allen probes data. The results show that most (83%) of them are detected with a low plasma density n(e)<20 cm(-3), and the wave tends to be stronger in the lower density region. QEMS waves would also become stronger when the proton ring (10 keV) is more pronounced and the suprathermal (tens to hundreds of eV) proton population is larger. Most of the QEMS waves, especially the intense ones, are confined in the dayside equatorial region (|MLAT| < 3(degrees)). The wave frequencies are typically slightly below the multiples of proton gyro-frequency, and the wave amplitude gradually decreases with the increase of harmonic number. Our results further demonstrate that low plasma densities and abundant suprathermal protons are beneficial for intensifying QEMS waves and reveal the spatial distribution and frequency spectral characteristics of QEMS waves.
关键词：
Distribution network;Unmanned aerial vehicle (UAV);Image segmentation;Improved weIghted meaN oF vectOrs (IINFO)
摘要：
Distribution grid network has problems such as long mileage, large scale, complex surrounding environment, and aging of equipment. It is the development trend of power distribution network operation and maintenance to use unmanned aerial vehicles to patrol and combine with image processing technology for intelligent detection of equipment status. Image segmentation is well-known technique for extracting defect regions of equipment from distribution network inspection images. Therefore, this paper proposes an efficient a novel multilevel thresholding segmentation method to improve the fault diagnosis process with an improved weighted mean of vectors optimization (IINFO) algorithm. The IINFO algorithm adopts various measures to improve the optimization results, including Gaussian mutation to increase the local search ability and range of the optimal individual, Cauchy mutation to enhance the global search ability of its vector individual, reflective learning operators to strengthen self-learning and avoid local optimal solutions, and parallel operation to improve the utilization of computational resources. Moreover, two-dimensional Kapur cross-entropy is used as an objective function to solve the multilevel thresholding problem. The proposed method is evaluated using benchmark functions and distribution network inspection image datasets and is compared with 12 other metaheuristic algorithms. The results demonstrate that the proposed method has better performance and a higher ability to find optimal solutions compared to the other algorithms. These findings suggest that our method may be useful in improving the accuracy and efficiency of distribution network inspections and have significant potential for practical applications.
期刊：
IEEE Transactions on Industry Applications,2024年60(1):1208-1218 ISSN：0093-9994
作者机构：
[Xian Zhang; Rongwu Zhu] School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen, China;[Guanchen Yu] College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen, China;[Hong Wang] Electric Power Research Institute, China Southern Grid, Guangzhou, China;School of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha, China;Shenzhen United Times Energy Internet Research Institute, Shenzhen, China
摘要：
With the pressure of energy crisis, how to achieve low carbon and self-sustaining operation of highway transportation network (HTN) has become an emerging research topic. In the current HTN, fuel vehicles (FVs) and electric vehicles (EVs) form a mixed traffic flow together. In this context, a novel model is proposed for the planning of energy facilities in HTN, including the construction of charging stations and the retirement of gas stations, which takes into account not only the balance of traffic flow but also environmental factors in the planning process. Meanwhile, the construction of charging stations leads to the coupling of HTN and distribution network (DN). In order to further achieve the goal of carbon reduction, a planning framework of low carbon facilities in the charging system is proposed, including the installation of photovoltaic (PV) panels and carbon capture and storage (CCS) systems. Finally, the rationality of the proposed planning method is verified by case studies. IEEE
关键词：
Integrated energy system;Renewable energy;Carbon reductions;Attention;Multi-agent deep deterministic policy gradient
摘要：
In a multi-regional integrated energy system (MIES), optimal scheduling under random renewable supply and user demand is crucial to promote the process of carbon neutrality. Further, the total carbon emission of multiple regions is expected to strictly restricted under a threshold, while intensifying the complex coupling of multiple agents. To address the optimal dispatching problem, we establish a typical MIES model with the global carbon emission constraint, which is formulated as a partially observable Markov decision-making process (POMDP). Then we propose an improved multi-agent deep deterministic policy gradient (MADDPG) method, which utilizes a centralized training and decentralized execution (CTDE) framework to effectively improve the multi-agent stationarity. Moreover, an attention mechanism is employed to enhance the efficiency of communication and coordination among agents. Experiments are carried out on multi-regional datasets, and the results certify that the proposed algorithm can decrease system operation costs, reduce carbon emissions, and speed up the convergence of the multi-agent system.
摘要：
The problem of fault estimation is addressed for one-dimensional (1-D) linear boundary control and boundary observation (BCBO) parabolic partial differential equations (PDEs) with a faulty boundary measurement. The considered plant is subjected to simultaneous unknown multiplicative faults entering the boundary input and boundary measurement. Difficulties arise due to the coupling between the sensor fault parameter and unknown boundary state appearing in the measurement. With the only boundary input and faulty boundary measurement, it is rather challenging to estimate the accurate values of faults and state simultaneously. Therefore, most existing results only consider correct and healthy measurement for PDE systems. To this end, novel adaptation laws and an adaptive observer are designed in this work to provide exponential convergent joint fault-state estimation, where we design and leverage a set of novel filters. It is first time that unknown multiplicative fault parameter in the measurement can be estimated accurately in the PDE systems.
作者机构：
[Hao Xu; Haoren Luo] School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, China;[Yujia Wang; Jianhong Su] International Institute of Engineering, Changsha University of Science & Technology, Changsha 410114, China;Author to whom correspondence should be addressed.;[Chenhao Sun] School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
通讯机构：
[Chenhao Sun] S;School of Electrical & Information Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
protection setting;distributed power grid;independent factor evaluation;quantum genetic optimization
摘要：
To ensure a stable and reliable power supply, the valid and timely response of protective relays are indispensable. Through the prevention of fault expansions, potential equipment damage or system collapse can be averted, where their setting is one vital prerequisite for such effective implementations. However, the increasing complexity of distribution power systems results in more challenges for protection tuning strategies. Ergo, this paper presents an ensemble that combines the independent factor evaluation (IFE) and quantum genetic optimization (QGO) models to further optimize the performance of relays according to their distributed tuning environment. In this ensemble, both near and far-end fault characteristics can be incorporated. In the first stage, the IFE dimensional reduction model is deployed for massive heterogeneous input data, where the statistical independence of input signals is calculated, the linear transformation matrix to decouple mixed signals is found, the linear combination of such signals is formed, and the non-Gaussian property to sort them is established. This can ameliorate the following calculation efficiency under those high-dimensional data scenarios. Subsequently, the QGO model is designed to further improve relay settings, where qubit representation is built to reduce required chromosomes, the linear superposition of the optimal solution probability in different states is implemented for a better diversity and convergence performance, and a self-adaption quantum gate is established to dynamically update the qubit chromosome groups and two-state solution combinations. Lastly, an empirical case study is presented, which validates the enhanced convergence, accuracy, and rapidity of the proposed ensemble.
关键词：
Damping;Oscillators;Power system stability;Power system dynamics;Impedance;Voltage control;Stability criteria;Grid forming converter;virtual synchronous generator;droop control;interaction mechanism;stability margin;low frequency oscillation;loop shaping;lead compensator
摘要：
Grid-forming converters (GFC) are promising technology for improving the grid inertia and frequency stability via voltage source converters (VSC). However, GFCs could make the ac-side oscillations more complicated since it mimics the dynamics of synchronous generators (SG), and the ac-side oscillations could spread to the dc systems. This paper investigates the mechanism of the interactions between GFCs and ac grids, and proposes an enhanced GFC to improve the damping performance on oscillations. By separating the system model into GFC-related transfer functions (TF) and the ac grid-related TFs, the interaction and stability margin can be investigated by the phase difference of these TFs at the cross-gain frequency (CGF). A lead compensator is designed to reshape the phase characteristic of GFC-related TF for enhancing the damping performance of the GFC. The effectiveness of the enhanced GFC is tested according to the simulations on DIgSILENT/PowerFactory.
通讯机构：
[He, Y ] C;Changsha Univ Sci Technol, Sch Elect & Informat Engn, Changsha 410114, Peoples R China.
摘要：
This study suggests an improved chaos sparrow search algorithm to overcome the problems of slow convergence speed and trapping in local optima in UAV 3D complex environment path planning. First, the quality of the initial solutions is improved by using a piecewise chaotic mapping during the population initialization phase. Secondly, a nonlinear dynamic weighting factor is introduced to optimize the update equation of producers, reducing the algorithm's reliance on producer positions and balancing its global and local exploration capabilities. In the meantime, an enhanced sine cosine algorithm optimizes the update equation of the scroungers to broaden the search space and prevent blind searches. Lastly, a dynamic boundary lens imaging reverse learning strategy is applied to prevent the algorithm from getting trapped in local optima. Experiments of UAV path planning on simple and complex maps are conducted. The results show that the proposed algorithm outperforms CSSA, SSA, and PSO algorithms with a respective time improvement of 22.4%, 28.8%, and 46.8% in complex environments and exhibits high convergence accuracy, which validates the proposed algorithm's usefulness and superiority.
摘要：
This letter investigates the dynamic coupling mechanism between voltage and frequency in a virtual synchronous generator (VSG) system, where a unified model is proposed for the analysis of voltage stability, frequency stability and voltage-frequency coupled stability. The results show that voltage/frequency stability is impacted by both self- and coupled-dynamics. Moreover, voltage and frequency oscillate at the same oscillation frequency if the voltage-frequency coupled instability occurs. However, the frequency oscillation occurs while voltage magnitude maintains stability if voltage self-dynamics behaves a negative feedback effect. The time-domain simulation is performed to validate the rationality of the theoretical analysis.
作者机构：
[Heng Jiao; Jun Xiao; Zihan Lv] Key Lab of Smart Grid of Education Ministry, Tianjin University, Tianjin 300072, China;State Grid Tianjin Electric Power Research Institute, Tianjin 300384, China;[Chenhui Song] School of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha 410114, China;[Zhenyu Bao] Ningbo Power Supply Company of State Grid Zhejiang Electric Power Co., Ltd, Ningbo 315000, China;[Zekai Qiu] State Grid Shaanxi Electric Power Research Institute, Xi'an 710100, China
通讯机构：
[Jun Xiao; Guoqiang Zu] K;Key Lab of Smart Grid of Education Ministry, Tianjin University, Tianjin 300072, China<&wdkj&>State Grid Tianjin Electric Power Research Institute, Tianjin 300384, China<&wdkj&>Key Lab of Smart Grid of Education Ministry, Tianjin University, Tianjin 300072, China
摘要：
This paper is the second in a two-part series on the concavity-convexity of the distribution system security region (DSSR). In Part I, the concave-convex characteristics and mechanism of DSSR are revealed by observing many case grids. In Part II (this paper), the concave-convex principle of DSSR is revealed through mathematical deduction. Firstly, the relevant concepts of sub-regions are proposed, and a DSSR model based on the union of sub-regions is developed. Secondly, the concave-convex principle of DSSR is proposed. The proposed criteria show that the security region of a distribution system with a single load transfer path for each feeder is convex, while that with multiple load transfer paths for some feeders can be concave or convex. Thirdly, the proposed criteria are deduced mathematically. Fourthly, based on the criteria, a method is proposed to judge whether a DSSR is concave or convex. Fifthly, the proposed criteria and method are verified through several cases, and the DSSR concavity-convexity of real distribution systems in China is also analyzed. Finally, the applications of DSSR concavity-convexity are illustrated. This work lays a mathematical foundation for the research of the topological properties of DSSR and is also useful for the application of DSSR.
作者：
Zhou, Enze;Wang, Lei;Wei, Ruizeng;Liu, Shuqing;Zhou, You
期刊：
Frontiers in Energy Research,2024年12:1330782 ISSN：2296-598X
通讯作者：
Zhou, EZ
作者机构：
[Wei, Ruizeng; Liu, Shuqing; Wang, Lei; Zhou, Enze] Elect Power Res Inst Guangdong Power Grid Co Ltd, Key Lab Power Equipment Reliabil Enterprise, Guangzhou, Guangdong, Peoples R China.;[Zhou, You] Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha, Hunan, Peoples R China.
通讯机构：
[Zhou, EZ ] E;Elect Power Res Inst Guangdong Power Grid Co Ltd, Key Lab Power Equipment Reliabil Enterprise, Guangzhou, Guangdong, Peoples R China.
关键词：
Wildfire occurrence probability;flame height;Insulation breakdown risk;Risk level;Risk distribution
摘要：
With the intensification of global climate change, the frequency of wildfires has markedly increased, presenting an urgent challenge in assessing tripping failures for power systems. This paper proposes an innovative method to evaluate the spatial wildfire-induced tripping risk of transmission lines based on a flame combustion model. Firstly, Bayes theory is employed to assess the spatial probability of wildfire occurrence. Subsequently, Wang Zhengfei's flame combustion model is utilized to estimate the potential flame height of wildfires along the transmission corridor. Thirdly, the insulation breakdown risk of the transmission line is calculated based on the relative height difference between the flame and the transmission line. Finally, the spatial wildfire-induced tripping risk of the transmission line is then determined by combining the wildfire occurrence probability and the insulation breakdown risk. A case study conducted in Guizhou province, China validates the accuracy of the proposed model. Utilizing ArcGIS, the wildfire occurrence probability distribution in Guizhou is visualized to enhance the efficiency of operation and maintenance. The results indicate that over 80% of wildfire incidents occurred in areas with occurrence probabilities exceeding 50%.
