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SSRN 2022年

作者： Zhou, Jing Zhu, Jiawei He, Weilan Cao, Yu Pang, Jinbo Ni, Jian Zhang, Jianjun School of Chemical Engineering Northeast Electric Power University Jilin132012 China Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology Ministry of Education School of Electrical Engineering Northeast Electric Power University Jilin132012 China University of Jinan Jinan250022 China College of Electronic Information and Optical Engineering Nankai University Tianjin300350 China

Antimony selenide (Sb2Se3) has rapidly emerged in the field of photovoltaics using one-dimensional crystal structure. However, the power conversion efficiency (PCE) of Sb2Se3 solar cells is influenced by the orientation of the Sb2Se3 photoactive layers. In this study, we investigate the influence of substrate properties on the preferred orientation and microstructure of Sb2Se3 films systematically. With the rise of substrate surface temperature and the decline of substrate surface bonding energy, the preferred orientation of the Sb2Se3 films altered from (hk0) to (hk1) and finally to (002). After summarizing the performance of different preferentially oriented Sb2Se3 solar cells, the results showed that the (hk0)-preferentially oriented devices exhibited a poor performance of less than 1.1%. As the preferred orientation of Sb2Se3 absorbers changed from (hk0) to (hk1), the carrier transport changed from inter-ribbon charge hopping to transportation along the (Sb4Se6)n ribbons. This enhanced the carrier transport efficiency, thereby leading to the enhancement of the PCE to 2%–3%. Furthermore, when the (002) texture coefficient (TC) of the Sb2Se3 films was between 1.8 and 3.6, the PCE of the devices was further enhanced to above 3.5%. A maximum PCE of 4.79% can be obtained when the (002) TC was 3.24. This study reveals the relationship between the Sb2Se3 film preferred orientation and device performance, and demonstrates an effective way to precisely control the Sb2Se3 film microstructure to obtain a high PCE. © 2022, The Authors. All rights reserved.

关键词： Selenium compounds

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Synchronization Stability of PLL-Based power Converters Connected to Weak AC Grid

Synchronization Stability of PLL-Based Power Converters Conn...

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power and Electrical Engineering (ACPEE), 5th Asia Conference on

作者： Limin Mei Lei Ding Zhihao Wang Deyu Cai Ran Ding Jingran Wang Haixiang Xu Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan China Electric Power Dispatching and Control Center State Grid Jibei Electric Power Company Limited Beijing China

In this paper, the synchronization stability of converter system based on the phase-locked loop (PLL) is studied, especially when it is connected to a weak AC grid. First, the small signal model considered PLL, power control, current control and voltage feedforward (VFF) control is built. The open-loop transfer function can analyze the stability of the system but hides the dynamic of PLL. So the conjugated circuit is proposed, which describes the dynamics of PLL and the other part separately. Based on the Bode diagrams, we explore how the grid impedance and converter controller parameters influence the stability of the system. In order to verify the analysis results, simulations are conducted in MATLAB/Simulink.

关键词： power control power system stability Stability analysis Circuit stability Synchronization Mathematical model Phase locked loops

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Distributed Emergency Frequency control Considering Transient Stability Constraints in Multi-Infeed Hybrid AC-DC system

arXiv

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arXiv 2022年

作者： Liu, Ye Shen, Chen Wang, Zhaojian The State Key Laboratory of Power Systems Department of Electrical Engineering Tsinghua University Beijing100084 China The Key Laboratory of System Control and Information Processing Ministry of Education of China Department of Automation Shanghai Jiao Tong University Shanghai200240 China

Due to possible emergency faults and frequency regulation reserve shortage in the multi-infeed hybrid AC-DC (MIDC) system, the emergency frequency control (EFC) with LCC-HVDC systems participating is important for system frequency stability. Nevertheless, the existing decentralized EFC strategies cannot guarantee the transient stability constraints of lines and cannot meet the frequency restoration requirement. To fill this gap, this paper proposes a complementary distributed EFC strategy. By selecting the semi-distributed or fully-distributed control law according to the state of AC system control center, the proposed distributed EFC can improve the control performance with a normal control center and enhance the control reliability in case of control center failure. Then, to derive the semi-distributed and fully-distributed control laws, a general design method is proposed by formulating an optimal EFC problem. Both of these two control laws can guarantee transient stability constraints, restore system frequency and achieve the defined optimal control objective. Moreover, the optimality of the closed-loop equilibrium is proven, and a Lyapunov analysis shows the asymptotic stability of the closed-loop system with the discontinuous control dynamics. A case study verifies the effectiveness of the proposed distributed EFC strategy. Copyright © 2022, The Authors. All rights reserved.

关键词： Asymptotic stability

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A Novel Hybrid Method for Fault Diagnosis of Industrial Equipment Based on Vibration Signals

A Novel Hybrid Method for Fault Diagnosis of Industrial Equi...

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Prognostics and system Health Management Conference (PHM-Qingdao)

作者： Sen Tao Kai Wang Peng Zeng Tianda Yu Hao Wu Key Laboratory of Networked Control Systems Chinese Academy of Sciences Shenyang China Shenyang Institute of Automation Chinese Academy of Sciences Shenyang China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang China University of Chinese Academy of Sciences Beijing China Shenyang China Nuclear Power Institute of China Chengdu China State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing China

Industrial equipment reliability is a critical issue that smart manufacturing systems must address. Implementation of online fault diagnosis for industrial equipment is a promising technology that can improve equipment reliability. Vibration analysis is a popular technique for equipment condition monitoring. For the non-linear and non-stationary features of industrial vibration signals, a hybrid model based on wavelet transform (WT), support vector machine (SVM), and grey wolf optimization algorithm (GWO) is proposed. The time-frequency domain features of fault signals are extracted by wavelet transform to solve the non-linearity of signals, and the obtained feature vectors are input into SVM for classification. Aiming at the problem of setting penalty coefficient and kernel function parameters, GWO is introduced to seek hyperparameters by using the hunting principle of wolves. In the experimental part, firstly, the comparison of the GWO-WT-SVM, GWO-SVM and SVM models was carried out. Secondly, Comparison with classical classification algorithms is made. Apparently, the GWO-WT-SVM model achieves higher accuracy than other models in bearing fault diagnosis.

关键词：

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Probabilistic evaluation of renewable energy curtailment under forward electricity market 10

Probabilistic evaluation of renewable energy curtailment und...

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2020 10th International Conference on power, Energy and Electrical Engineering, CPEEE 2020

作者： Jiang, Jiheng Qiao, Ying Lu, Zongxiang Ran, Liang Ma, Ming Li, Jin Wang, Feng State Key Lab of Control and Simulation of Power Systems and Generation Equipments Dept. of Electrical Engineering Tsinghua University Beijing100084 China State Grid Gansu Provincial Electric Power Company Lanzhou730000 China Key Laboratory of Wind Power Integration Operation and Control of Gansu Province Lanzhou730070 China

Forward electricity market has emerged as a pivotal section for the electricity transaction to keep stakeholders away from price risk and electricity shortage. But the forward contract of conventional unit partially limits the unit output before operation, leading to the curtailed generation share of renewable energy source (RES). Modeling and assessing this impact is of great significance for system planning and market supervision. The central thesis of this paper is to find out the impact of forward market on RES curtailment. A probabilistic evaluation model for RES accommodation is proposed, taking the curtailment rate as a main evaluation index. We mainly research financial contract and physical contract, modeling the impact of them on thermal unit minimum load capacity and power load in evaluation model. The simulation is conducted in a simplified system, which reveals the change of RES curtailment with renege penalty, contract price and execution generation curve. © 2020 The Authors, published by EDP Sciences.

关键词： power markets

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Integral Inequalities for the Analysis of Distributed Parameter systems: A Complete Characterization via the Least-Squares Principle

arXiv

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arXiv 2023年

作者： Feng, Qian Seuret, Alexandre Nguang, Sing Kiong Xiao, Feng School of Control and Computer Engineering North China Electric Power University Beijing China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China Dpto de Ingeniería de Sistemas y Automática Universidad de Sevilla Camino de los Descubrimientos Sevilla Spain Department of Electrical Computer and Software Engineering The University of Auckland New Zealand

A wide variety of integral inequalities (IIs) have been developed and studied for the stability analysis of distributed parameter systems using the Lyapunov functional approach. However, no unified mathematical framework has been proposed that could characterize the similarity and connection between these IIs, as most of them was introduced in a dispersed manner for the analysis of specific types of systems. Additionally, the extent to which the generality of these IIs can be expanded and the optimality of their lower bounds (LBs) remains open questions. In this study, we introduce two general classes of IIs that can generalize nearly all IIs in the literature. The integral kernels of the LBs of our IIs can contain an unlimited number of weighted L2 functions that are linearly independent in a Lebesgue sense. Moreover, we not only estalish the equivalence relations between the LBs of our IIs, but also demonstrate that these LBs are guaranteed by the least squares principle, implying asymptotic convergence to the upper bound when the kernels functions constitutes a Schauder basis of the underlying Hilbert space. Owing to their general structures, our IIs are applicable in a variety of contexts, such as the stability analysis of coupled PDE-ODE systems or cybernetic systems with delay structures. Copyright © 2023, The Authors. All rights reserved.

关键词： Least squares approximations

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A robust identification method for transmission line parameters based on BP neural network and modified SCADA data 4

A robust identification method for transmission line paramet...

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4th IEEE International Conference on Energy Internet, ICEI 2020

作者： Lu, Min Jin, Xueqi Wang, Xiaozhong Xu, Yan Wang, Yangyingfu Kong, He Gu, Lei Luo, Kaiyang Xue, Ancheng State Grid Zhejiang Electric Power Company Electric Power Dispatching Control Center Hangzhou China State Grid Zhejiang Electric Power Company Huzhou Power Supply Company Huzhou China North China Electric Power University State Key Laboratory of Alternate Electrical Power System with Renewable Energy Source Beijing China

ISBN: (纸本)9780738105000

Accurate transmission line (TL) parameters are the basis of power system calculations. In recent years, artificial intelligence (AI) develops rapidly, which has been applied widely in power systems. However, AI is rarely applied to TL parameter identification. Thus, combining the TL model and AI, this paper proposes a robust identification method for TL parameters combined with BP (back propagation) neural network and median robust estimation, with the modified SCADA measurements based on TL model. Specifically, first, the robust identification method for TL parameter combined with BP neutral network and median estimation is proposed. And then, the training set that considers various working conditions and different line parameters is constructed based on the π-equivalent model. Furthermore, the input data of BP neural network is construed by modifying the SCADA data based on TL model. In addition, the median estimation is used to obtain the final result, which could reduce the interference of noise. Finally, the results with simulated data and measured SCADA measurements data show the effectiveness and practicality of the proposed method, respectively. © 2020 IEEE.

关键词： Electric lines

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Research and Application of Simplified Service Bus in New Generation Dispatching Technical Support system and Heterogeneous system

Research and Application of Simplified Service Bus in New Ge...

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IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Yi Qiang Wan Shupeng Wang Zhemin He Weihua Zhang Ping Zhang Feng System R&D Center NARI Group Corporation(State Grid Electric Power Research Institute) NARI Technology Co. Ltd Nanjing China State Grid Shanxi Electric Power Co. Ltd Taiyuan China System R&D Center State Key Laboratory of Smart Grid Protection and Control Nanjing China

With the rapid development of UHV AC / DC hybrid power grid, in order to cope with the large-scale access of new energy, the power market reform has been continuously promoted. Therefore, it is proposed to build a new generation of dispatching technical support system to meet the needs of future power system development and safe, stable and high-quality operation. This paper proposes a simplified service bus that supports a new generation of service-oriented architecture, and meets the deployment characteristics of cloud terminals that are cross platform, lightweight, easy to deploy, open and efficient. The simplified service bus can well meet the location independent characteristics and be easily deployed in and out of the system. The flexible protocol processing mode cooperating with the gateway can meet the needs of accessing the services of the system and external systems. At the same time, it supports multiple man-machine network and automatic switching of service network shutdown under N-1 mode, which greatly improves the availability and stability of the system, Which Provide a strong guarantee for the safe, stable and efficient operation of the new generation system.

关键词： Cloud computing Protocols Switches system integration power system stability Logic gates Dispatching

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Fast Adaptive Auto-Reclosing Strategy of Mmc-Hvdc Transmission Line Based on Half-Bridge Pathway Injection Signal

SSRN

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SSRN 2022年

作者： Deng, Xiangli Wang, Peng Liao, Yuelin Zhao, Jinbin Liu, Shiming School of Electric Engineering Shanghai University of Electric Power Yangpu District Shanghai 200090 China State Grid Wenzhou Power Supply Company Zhejiang Province Wenzhou325000 China Key Laboratory of Power System Intelligent Dispatch and Control Shandong University Ministry of Education Ji’nan Shandong Province 250061 China

The probability of instantaneous grounding fault during overhead line transmission is high, and it is necessary to configure an efficient restart plan to restore the system. The traditional reclosing strategy is easy to cause secondary overcurrent shock when the permanent fault is reclosed. The conventional scheme based on active injection signal for fault identification during the reclosing period only considers single-pole identification and will affect the normal operation of the power grid. Aiming at the above problems, a fault identification method based on half-bridge modular multilevel converter (MMC) injection signal is proposed. The proposed method completes the identification of multiple types of faults during reclosing without affecting the normal operation of the sound pole line by adding a control strategy to the valve controller to cooperate with the dc circuit breaker to actively inject characteristic signals. The method has no special requirements for the topology of the MMC sub-module, improves the detection accuracy of the transition resistance, quickly identifies the fault, and has little impact on the power grid operation. The four-terminal MMC-HVDC simulation model is built on PSCAD/EMTDC, and the simulation results verify the effectiveness of the proposed method. © 2022, The Authors. All rights reserved.

关键词： Poles

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Fault Diagnosis of Wind Turbine Gearbox Based on SSDAE-ELM

Fault Diagnosis of Wind Turbine Gearbox Based on SSDAE-ELM

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第33届中国控制与决策会议

作者： Jianhua Zhang Haibo Dong Rui Shan Guolian Hou Congzhi Huang State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University School of Control and Computer Engineering North China Electric Power University

In recent years,the installed capacity of wind turbine is increasing year by year,and the influence of wind turbine faults on wind farm operation is also *** this paper,a novel fault diagnosis method is proposed to diagnose the fault of wind turbine *** method is based on stacked sparse denoising auto-encoders(SSDAE)neural network which combines stacked sparse auto-encoders(SSAE) neural network and stacked denoising auto-encoders(SDAE) neural network to extract features from high-dimensional signal data *** addition,extreme learning machine(ELM) classifier is used to finish the fault diagnosis according to the features extracted from high-dimensional signal data by the ***,the method is tested based on the simulation experiment,the simulation results demonstrate that the accuracy of this fault diagnosis method is higher than that of other methods when the same parameters are used.

关键词： Wind Turbine Gearbox Deep Learning Stacked Sparse Denoising Auto-encoders Fault Diagnosis

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