作者机构:
[陈春; 黄俊贤; 孙辰昊; 曹一家] School of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha;410114, China;[李勇] School of Electrical and Information Engineering, Hunan University, Changsha;410082, China;[陈春; 黄俊贤; 孙辰昊; 曹一家] 410114, China
通讯机构:
[Huang, J.] S;School of Electrical and Information Engineering, China
关键词:
配电网风险状态;多维度评估;健康度;重要度;多源异构数据
摘要:
配电网运行风险状态的全面评估对电力系统的安全可靠运行具有重要意义。为此,综合考虑外部环境条件和内部电气参数,定义配电线路健康度和重要度,提出一种多源异构数据分布下的配电网风险状态多维评估方法。首先,健康度由外部环境信息分...展开更多 配电网运行风险状态的全面评估对电力系统的安全可靠运行具有重要意义。为此,综合考虑外部环境条件和内部电气参数,定义配电线路健康度和重要度,提出一种多源异构数据分布下的配电网风险状态多维评估方法。首先,健康度由外部环境信息分析,离散环境特征通过改进的关联规则挖掘(associationrulemining,ARM)方法处理,从而能深入探索和分析稀有因子,并通过部件关键度度量(component importance measure,CIM)优化元素相对权重计算方法,进一步提高诊断准确度,连续特征由分层概率模糊推理系统(hierarchical probabilistic fuzzy inference system,HPFIS)处理,分层结构的应用减少了运算复杂性,概率模糊能具体诊断连续特征中的罕见元素。其次,重要度由电气参数分析,利用二阶锥规划和启发式规则(second order cone programming and heuristic rules,SOCPHR)的配电网故障恢复模型求解故障失电后果,继而反映内部用户对供电可靠性需求的差异。基于以上,构建了ARM-CIM-HPFIS-SOCPHR(ACHS)评估模型,最后,通过对39节点和84节点实际配电系统进行仿真验证,描述了风险状态二维映射图。研究表明所提方法能有效评估配电网运行风险状态,便于检查和维护。收起
关键词:
integrated energy system;energy configuration optimization;coupling relationships;ICA-SAQGM ensemble
摘要:
As one representative smart energy infrastructure in smart cities, an integrated energy system (IES) consists of several types of energy sources, thus making more complicated coupling connections between the supply and demand sides than a power grid. This will impact when allocating different energy sources to ensure the appropriate energy utilization in the IES. With this motivation, an IES energy configuration optimization strategy based on a multi-model ensemble is proposed in this paper. Firstly, one coupling model is constructed to assess the underlying collaborative relationships between two sides for a renewable-energy-connected IES. Next, the independent component analysis (ICA) method is implemented for noise reduction in massive heterogeneous input databases, which can effectively improve the computing efficiency under such high-dimensional data conditions. Also, the self-adaptive quantum genetic model (SAQGM) is built for subsequent configuration optimization. Specifically, the quantum bit representation is incorporated to reduce computation complexity in multi-states scenarios, the double-chain formation of chromosomes is deployed to diminish the uncertainty when encoding, and the dynamic adaptation quantum gate is established to successively amend parameters. Finally, an empirical case study is conducted which can demonstrate the benefits of this strategy in terms of feasibility, efficiency, and economy.
关键词:
Power distribution system failure risks;Risk-early-warning;Spatiotemporal imbalanced data;AREcffr
摘要:
Power distribution systems are susceptible to external environmental disturbances. The early warning of po-tential fault risks in both spatial and temporal scales can assist in maintenance planning and overhaul scheduling for distribution systems, thus their overall reliability consequently. To achieve it, this paper proposes a self-adaptive prediction model for future failure risks in distribution systems, namely the association rules explo-ration with conditional filter and fitness regulation (AREcffr). In this approach, electrical attributes along with surrounding condition factors are both implemented as inputs. Then, to cope with the commonly-occurred imbalanced data distribution in both two scales when distinguishing risky factors, the conditional importance diagnostic threshold setting and importance diagnostic standard calculation methods set are designed. In that case, the included high-risk-low-probability (HRLP) time series and condition factors in the sparsely distributed input data can be taken into the assessment. Next, to conduct more reasonable measurements of risk levels for those selected risky components, a component importance measure (CIM)-based relative weight analysis model, which is according to the variation of total system risks caused by each risky component rather than its appearance frequency or database share, is established. Finally, an empirical research is presented, and the flexibility and advantages of this risk-early-warning model can be validated and demonstrated in consequence.
摘要:
现有配电网故障定位方法严重依赖波头到达时间、固有频率值等单一特征量,在微弱故障条件下难以有效提取故障特征,故障定位精度低。对此,提出基于全景故障特征挖掘的配电网单端行波定位方法。首先,分析不同故障点行波传输过程,结合小波能量熵量化分析行波全景波形时频分布特性:行波全景波形各次波头频率分布包含了故障支路信息,典型波头到达时序包含了故障距离信息,行波全景波形与故障位置一一对应,即不同故障位置的行波全景波形具有唯一性;在此基础上,以行波全景波形作为输入样本,搭建以卷积神经网络(convolutional neural network,CNN)与长短期记忆(long short term memory,LSTM)神经网络为核心的深度学习混合模型,CNN提取各次波头频率分布特征,挖掘故障支路信息,LSTM提取典型波头时间关联特征,挖掘故障距离信息,在网络中设置双通道并联输出层,其中分类层输出故障支路,回归层输出故障距离,最终实现配电网故障精确定位。仿真结果表明:在含有大量微弱故障样本的测试集上,定位平均绝对误差为67m,在3kΩ故障条件下定位误差仅为111m。
摘要:
Abstract: The interpretation of optical and synthetic aperture radar (SAR) images in remote sensing is general for many tasks, such as environmental monitoring, marine management, and resource planning. Instance segmentation of optical and SAR images, which can simultaneously provide instance-level localization and pixel-level classification of objects of interest, is a crucial and challenging task in image interpretation. Considering that most current methods for instance segmentation of optical and SAR images rely on expensive pixel-level annotation, we develop a weakly supervised instance segmentation (WSIS) method to balance the visual processing requirements with the annotation cost. First, we decompose the prior knowledge of the mask-aware task in WSIS into three meta-knowledge components: fundamental knowledge, apparent knowledge, and detailed knowledge inspired by human visual perception habits of “whole to part” and “coarse to detailed.” Then, a meta-knowledge-guided weakly supervised instance segmentation network (MGWI-Net) is proposed. In this network, the weakly supervised mask (WSM) head can instantiate both fundamental knowledge and apparent knowledge to perform mask awareness without any annotations at the pixel level. The network also includes a mask information awareness assist (MIAA) head, which can implicitly guide the network to learn detailed information about edges through the boundary-sensitive feature of the fully connected conditional random field (CRF), facilitating the instantiation of detailed knowledge. The experimental results show that the MGWI-Net can efficiently generate instance masks for optical and SAR images and achieve the approximate instance segmentation results of the fully supervised method with about one-eighth of the annotation production time. The model parameters and processing speed of our network are also competitive. This study can provide inexpensive and convenient technical support for applying and promoting instance segmentation methods for optical and SAR images. Keywords: remote sensing; weakly supervised instance segmentation; meta-knowledge; optical images; synthetic aperture radar images
期刊:
IEEE Transactions on Network Science and Engineering,2023年:1-12 ISSN:2327-4697
作者机构:
[Bangzhe Yin] Shaoyang Power Supply Company, State Grid Hunan Electric Power Company Limited, Shaoyang, China;UNEP DTU Partnership, Technical University of Denmark, Copenhagen, Denmark;Energy Resources, Development and Environment (ERDE) Lab, University of British Columbia, Vancouver, BC NSW, Canada;[Hongming Yang; Dingzhong Xu; Sheng Xiang; MingYong Lai] International Joint Laboratory of Ministry of Education for Operation and Planning of Energy Internet based on Distributed Photovoltaic-Storage Energy, Hunan Provincial Engineering Research Center for Electric Transportation and Smart Distribution Network, School of Electrical and Information Engineering, Changsha University of Science and Technology, Changsha, China;[Archie James Johnston] University of Sydney, Sydney, Australia
摘要:
To improve the power supply ability, heat supply ability, and waste recovery rate, a recycling electricity/heat rural supply system with waste feedstock is established. The energy supply system generates electricity/heat from biomass energy produced by wastes, which is also coupled to distributed renewable energy. The optimal scheduling of the established rural system will improve energy efficiency and cause emission reduction. Firstly, the waste recovery process is presented, and the architecture of the energy supply system is designed for the 100% absorption of renewable energy in rural areas. A carbon accounting model based on the locational marginal carbon emission factor is introduced, which considers the power exchange with the bulk power system and the carbon emission of biomass. Secondly, the optimal scheduling model for the recycling energy supply system is proposed to minimize both the total cost of energy supply and carbon emission, based on the constraints of energy balancing of electricity and heat, net carbon emissions, waste supply, etc. Finally, the IEEE 15-node system and PG&E 69-node system are employed for verification purposes. The proposed model contributes to 100% absorption of renewable energy and the efficient utilization of waste through the optimal cooperation of the waste supply, biomass power generation, and biomass heat, thereby supporting the achievement of zero carbon. IEEE
通讯机构:
[Deng, F ] ;Changsha Univ Sci & Technol, Coll Elect & Informat Engn, Changsha 410076, Peoples R China.
关键词:
Fault location;single end;traveling wave full waveform;convolution neural network;feature extraction
摘要:
Conventional single-ended traveling wave fault location methods, which commonly depend on partial features of traveling wavefronts, may lead to fault location failure, especially for weak-signal faults such as high impedance or zero-crossing faults and close-in faults. To tackle it, this article presents a fault location method according to the extracted panoramic features of traveling wave full waveform (TWFW) in time-frequency domains. Firstly, two rules of the TWFW features are probed, that is, the wavefront arrival sequence is varied from fault sections, as well as the frequency distribution of wavefronts is strongly related to the precise fault distance. Ergo, the mapping relationships between the TWFW and fault distance are qualitatively confirmed in order to demonstrate the uniqueness of the TWFW subsequently. Next, a LeNet-5-based convolution neural network (CNN) model is constructed to quantitatively evaluate such mapping relationships. In this model, various TWFW features will be extracted to the convolution channels when the CNN parameters are optimized adaptively, and the mapping relations can be formed in light of these sensitive features to estimate the fault distance. Finally, a Grad-CAM visualization method is deployed in the case study, and the accuracy along with the robustness of the proposed method in various fault conditions can be validated consequently.
摘要:
With the improvement of imaging equipment, hyperspectral underwater target detection (HUTD) has raised much interest in recent years. The existing HUTD methods do not fully use spectral characteristics and need prior information about targets. Besides, the detection performance lacks verification in natural scenarios. In this article, the authors propose a feature-band-based unsupervised underwater target detection method (FBUD), which aims at finding the optimal feature bands to identify the underwater target near the coastline. Specifically, the normalized difference water index (NDWI) and unmixing technique are adopted to find the target and background pixels. Then, the spectral difference between the target and background is used to find the feature bands. With a simple and fast math operation of the feature bands, the probability map of the underwater target can be easily obtained. Besides, a new unmanned aerial vehicle (UAV)-borne hyperspectral image (HSI) dataset named HNU-UTD is built for underwater target detection in real-world scenes. Experimental results obtained with the HNU-UTD dataset confirm the accuracy and effectiveness of the proposed detection method, which even outperforms supervised detection methods.
摘要:
Pansharpening has benefited from the development of deep learning (DL) and has achieved excellent results. However, most DL-based methods extract local features by convolutional neural networks and do not integrate global features. Moreover, these methods only extract high-frequency features on the high-pass domain (HPD) or only consider image features on the intensity domain (ID). The method that only considers features in one domain may result in insufficient extraction of spatial and spectral features. Therefore, we propose a dynamic local-global network model on dual-domains, that is, HPD and ID. The dynamic local-global feature extraction block (DLGB) is designed to dynamically integrate local and global features to improve the representation capability of the network. To decrease the computational complexity of global feature extraction, a lightweight biaxial nonlocal attention (BNLA) that captures global spatial features in horizontal and vertical directions is proposed. Experiments on GeoEye-1, QuickBird, and WorldView-3 datasets show that the proposed method presents better fusion performance on objective evaluation indices and subjective perception.
期刊:
JOURNAL OF FIRE SCIENCES,2023年42(1):22-62 ISSN:0734-9041
通讯作者:
Zhou, TJ
作者机构:
[Zhou, Tejun; Wu, Chuanping; Lu, Jiazheng; Zhou, TJ] State Key Lab Disaster Prevent & Mitigat Power Tra, Changsha 410007, Peoples R China.;[Zhou, Tejun] Changsha Univ Sci & Technol, Sch Elect & Informat Engn, Changsha, Peoples R China.
通讯机构:
[Zhou, TJ ] S;State Key Lab Disaster Prevent & Mitigat Power Tra, Changsha 410007, Peoples R China.
关键词:
Wildfires near transmission line;helicopters;spray live insulators
摘要:
Journal of Fire Sciences, Volume 42, Issue 1, Page 22-62, January 2024. <br/>Regarding the problem that helicopters cannot spray live transmission conductors and wildfires directly under an insulator, we built a full-scale 500 kV insulator flashover test platform to simulate high-altitude helicopters spraying fire extinguishing agents. The chemical formulation, spray intensity, and fragmentation method of the fire extinguishing agents were varied. We simulated the breakdown characteristics of insulators when helicopters spray fire extinguishing agents, revealing the mechanism of high-altitude live fire extinguishment for high-spray-intensity and high-conductivity agents. Furthermore, an insulation performance verification test of a helicopter spraying live equipment at different flight speeds and altitudes was carried out, and the behavior of the fire extinguishing agents was divided into a five-zone diffusion law consisting of the (1) water column, (2) continuous water block, (3) semi-continuous water body, (4) large droplet particles, and (5) small droplet particles. We propose a spraying live transmission line method in which the helicopter flight height and speed jointly control the particle size of the fire extinguishing agent. When the particle size of the fire extinguishing agent at the terminal is controlled to 560–4000 μm, the insulation performance of the fire extinguishing agent can be effectively improved. During high-incidence periods of wildfires, such as the Spring Festival and Qingming Festival in 2023, on-site firefighting on the Hunan power grid was performed using helicopters to spray fire extinguishing agents from top to bottom through live transmission conductors to extinguish wildfire disasters directly below the transmission conductors. Neither transmission line flashovers nor power outages occurred when the fires were extinguished.
摘要:
This paper proposes a decoupling control method to eliminate frequency coupling in three-phase grid-tied system. Firstly, the admittance model of three-phase <italic>LCL</italic>-type three-phase grid-tied converter (GTC) considering DC-bus voltage control (DVC) loop and phase-locked loop (PLL) is established in <italic>dq</italic>-domain frame, and the influence of asymmetrical DVC and PLL control structure on frequency coupling oscillation is analyzed. Then decoupling factors are added to the DVC loop and current control (CC) loop to achieve that the off-diagonal elements of the sequence admittance matrix of the GTC are 0, which means the frequency coupling in the GTC is eliminated. Therefore, the GTC system can be regarded as a single input single output (SISO) system, and the stability can be analyzed by the classic Nyquist criterion in the sequence-domain frame. Compared with the double input double output (DIDO) system, the resulted SISO system convenient for calculating the stability margin of the system and guiding parameter design. In addition, the SISO system is easier to be analyzed on the oscillation and resonance mechanism, and the analysis results can be used to optimize the design of the converter controller, grid planning and operation. Finally, simulation and experiment verify the feasibility and effectiveness of the proposed decoupling control method. IEEE