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1,902 results on '"Wang, Xianwei"'

1. Critical link identification of power system vulnerability based on modified graph attention network

Author

Wang, Changgang, Wang, Xianwei, Cao, Yu, Li, Yang, Lv, Qi, and Zhang, Yaoxin

Subjects
Electrical Engineering and Systems Science - Systems and Control
Abstract

With the expansion of the power grid and the increase of the proportion of new energy sources, the uncertainty and random factors of the power grid increase, endangering the safe operation of the system. It is particularly important to find out the critical links of vulnerability in the power grid to ensure the reliability of the power grid operation. Aiming at the problem that the identification speed of the traditional critical link of vulnerability identification methods is slow and difficult to meet the actual operation requirements of the power grid, the improved graph attention network (IGAT) based identification method of the critical link is proposed. First, the evaluation index set is established by combining the complex network theory and the actual operation data of power grid. Secondly, IGAT is used to dig out the mapping relationship between various indicators and critical links of vulnerability during the operation of the power grid, establish the identification model of critical links of vulnerability, and optimize the original graph attention network considering the training accuracy and efficiency. Thirdly, the original data set is obtained through simulation, and the identification model is trained, verified and tested. Finally, the model is applied to the improved IEEE 30-node system and the actual power grid, and the results show that the proposed method is feasible, and the accuracy and speed are better than that of traditional methods. It has certain engineering utilization value., Comment: in Chinese language

Published
2024
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8. A current deviation control parameter tuning method to suppress subsequent commutation failure

Author

LI Juan, ZHU Longzhen, ZU Lifeng, WANG Xianwei, and YANG Meijuan

Subjects
high voltage direct current, fault recovery process, subsequent commutation failure, suppression measures, current deviation control, cigre standard test model, Applications of electric power, TK4001-4102
Abstract

If a subsequent commutation failure occurs in the line commutated converter-based high voltage direct current (LCC-HVDC) transmission system, it will have a seriously negative impact on the safe and stable operation of the AC-DC hybrid power grid. Aiming at the problem of commutation failure during the current deviation control stage in the fault recovery process of the LCC-HVDC system, the relationship between current deviation control parameter and commutation failure is analyzed theoretically. It is found that to avoid commutation failure at this stage, the DC voltage and AC commutation voltage at the inverter side of the LCC need to meet certain constraints. These constraints are directly affected by the current deviation control parameter. Based on the theoretical analysis results, a current deviation control parameter tuning method is proposed, which can improve the control requirements for DC voltage recovery speed and degree during the fault recovery process of the system. The method makes it easier for the system to meet the stable operation constraints between DC voltage and AC commutation voltage, thereby reducing the probability of subsequent commutation failure. Finally, the CIGRE standard test model in the PSCAD/EMTDC simulation platform is used to verify the correctness of the theoretical analysis and the effectiveness of the parameter tuning method.

Published
2024
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30. Processable polyimide resins and their composites for long-term application at 300 ℃

Author

HU Hai, MENG Xiangsheng, KE Hongjun, WANG Xianwei, LI Xianming, GONG Dirong, and WANG Zhen

Subjects
processable, high temperature resistance, polyimide resin, carbon fiber composite, isothermal aging, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

A series of processable and high-temperature resistant polyimide resins terminated with 4-phenylethynyl phthalic anhydride were synthesized by PMR (for in situ polymerization of monomer reactants) using isopropyl alcohol as esterifying agent. The resin solution stored at room temperature for sixteen weeks has no solid precipitation, and the viscosity of the solution does not change significantly, which shows good storage stability at room temperature. The minimum melt viscosity of the imide oligomers is less than 300 Pa·s, which is suitable for compression moulding or autoclaved process. The cured polyimides exhibit extremely high glass transition temperatures (Tg) up to 462℃. The flexural strength and modulus of T300/PMR-PE-2 carbon fiber composite are 963 MPa and 53 GPa, respectively. The inter-laminar shear strength of the composite is 56 MPa. Moreover, the composite can maintain no lower than 66% of their room temperature mechanical properties at 300℃. After isothermal aging in air atmosphere for 500 h at 300℃, the mass loss of the composite is only 0.96%, meanwhile, the composite retention rate maintains 72% of its room temperature flexural strength and 98% of its room temperature inter-laminar shear strength, which demonstrates its excellent thermal-oxidative aging resistance.

Published
2023
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34. Renin–Angiotensin–Aldosterone System and LOX-1 Interaction in Hypertension with a Focus on Modulation of the Immune System

Author

Cheng, Weijia, Shao, Fang, Mehta, Jawahar L., Wang, Xianwei, Dhalla, Naranjan S., Series Editor, Bolli, Roberto, Editorial Board Member, Goyal, Ramesh, Editorial Board Member, Kartha, Chandrasekharan, Editorial Board Member, Kirshenbaum, Lorrie, Editorial Board Member, Makino, Naoki, Editorial Board Member, Mehta, Jawahar L. L., Editorial Board Member, Ostadal, Bohuslav, Editorial Board Member, Pierce, Grant N., Editorial Board Member, Slezak, Jan, Editorial Board Member, Varro, Andras, Editorial Board Member, Werdan, Karl, Editorial Board Member, Weglicki, William B., Editorial Board Member, Bhullar, Sukhwinder K., editor, and Shah, Anureet K., editor

Published
2023
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41. Research on AGV task path planning based on improved A* algorithm

Author

Wang Xianwei, Ke Fuyang, and Lu Jiajia

Subjects
Autonomous guided vehicle (AGV), Map modeling, Global path planning, Improved A* algorithm, Path optimization, Bezier curves, Computer engineering. Computer hardware, TK7885-7895
Abstract

Background: In recent years, automatic guided vehicles (AGVs) have developed rapidly and been widely applied in intelligent transportation, cargo assembly, military testing, and other fields. One of the key issues in these applications is path planning. Global path planning results based on known environmental information are used as the ideal path for AGVs combined with local path planning to achieve safe and fast arrival at the destination. The global planning method planning results as the ideal path should meet the requirements of as few turns as possible, short planning time, and continuous path curvature. Methods: We propose a global path-planning method based on an improved A * algorithm. And the robustness of the algorithm is verified by simulation experiments in typical multi obstacles and indoor scenarios. To improve the efficiency of pathfinding time, we increase the heuristic information weight of the target location and avoided the invalid cost calculation of the obstacle areas in the dynamic programming process. Then, the optimality of the number of turns in the path is ensured based on the turning node backtracking optimization method. Since the final global path needs to satisfy the AGV kinematic constraints and the curvature continuity condition, we adopt a curve smoothing scheme and select the optimal result that meets the constraints. Conclusions: Simulation results show that the improved algorithm proposed in this paper outperforms the traditional method and can help AGVs improve the efficiency of task execution by efficiently planning a path with low complexity and smoothness. Additionally, this scheme provides a new solution for global path planning of unmanned vehicles.

Published
2023
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