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Microstructure and properties of as-cast Cu-Cr-Zr alloys with lanthanum addition

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Journal of Rare Earths 2018年第4期36卷 424-429页

作者： Jilin Li Lili Chang Shengli Li Xinde Zhu Zhongxin An Department of Material Science and Engineering Shandong UniversityJinan 250061China Zhengzhou yutong bus co.Ltd. Zhengzhou 450061China

Cu-0.45 Cr-0.2 Zr-xLa（x = 0-0.48） alloys were prepared by vacuum casting. The effects of La addition and orientation on the microstructure and properties of the as-cast alloy were investigated by an optical microscope, a scanning electron microscope with an energy dispersive X-ray spectrometer, a tensile testing machine and an electrical conductivity tester. The result shows that the addition of La significantly refines the columnar grainsize and decreases the secondary dendrite arm spacing. Trace addition of La improves the room temperature ultimate tensile strength,elongation and electrical conductivity mainly by purifying during melting and casting. The ultimate tensile strength, elongation and electrical conductivity significantly decrease with the increase of La content due to formation of coarse particles and oxides, which severely harm the performance of the Cu-0.45 Cr-0.2 Zr-xLa alloys. The Cu-0.45 Cr-0.2 Zr-0.13 La alloy possesses a good combination of room temperature ultimate tensile strength, elongation and electrical conductivity. In addition, room temperature ultimate tensile strength and electrical conductivity along transverse direction of the ingot are higher than that along longitudinal direction,which is mainly ascribed to different distribution of grain boundary and grain orientation.

关键词： La Cu-Cr-Zr alloy Orientation Ultimate tensile strength Electrical conductivity Rare earths

A bus Planning Algorithm for FPC Design in complex Scenarios

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Chinese Journal of Electronics 2024年第2期33卷 346-352页

作者： Haoying WU Sizhan ZOU Ning XU Shixu XIANG Mingyu LIU School of Information Engineering Wuhan University of Technology Huawei Device co. Ltd.

Flexible printed circuit(FPC) design in complex scenarios has a list of pin concentration areas, which lead to extremely congested intersection regions while connecting the pins. Currently, it is challenging to explore the routability and to find topologically non-crossing and routable paths manually for the nets timely. The existing bus planning methods cannot offer optimal solutions concerning the special resource distribution of the FPC design. To investigate an effective way to shorten the routing time of FPC and achieve enhanced performance, a bus planning algorithm is proposed to tackle complex area connection problems. On the basis of the pin location information, the routing space is partitioned and generally represented as an undirected graph, and the topological non-crossing relationship between different regions is obtained using the dynamic pin sequence. considering the routability and electrical constraints, a heuristic algorithm is proposed to search the optimal location of the crossing point on the region boundary. Experimental results on industrial cases show that the proposed algorithm realize better performance in terms of count and routability in comparison with numerous selected state-of-the-art router and methods.

关键词： Flexible printed circuit Routability Non-crossing topology Heuristic algorithm

Carbon Emission Factors Prediction of Power Grid by Using Graph Attention Network

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Energy Engineering 2024年第7期121卷 1945-1961页

作者： Xin Shen Jiahao Li YujunYin Jianlin Tang Weibin Lin Mi Zhou Measurement Center Yunnan Power Grid Co.Ltd.Kunming650000China Electric Power Research Institute China Southern Power Grid Co.Ltd.Guangzhou510530China Guangdong Provincial Key Laboratory of Intelligent Measurement and Advanced Metering of Power Grid Guangzhou510530China

Advanced carbon emission factors of a power grid can provide users with effective carbon reduction advice,which is of immense importance in mobilizing the entire society to reduce carbon emissions.The method of calculating node carbon emission factors based on the carbon emissions flow theory requires real-time parameters of a power grid.Therefore,it cannot provide carbon factor information beforehand.To address this issue,a prediction model based on the graph attention network is proposed.The model uses a graph structure that is suitable for the topology of the power grid and designs a supervised network using the loads of the grid nodes and the corresponding carbon factor data.The network extracts features and transmits information more suitable for the power system and can flexibly adjust the equivalent topology,thereby increasing the diversity of the structure.Its input and output data are simple,without the power grid parameters.We demonstrated its effect by testing IEEE-39 bus and IEEE-118 bus systems with average error rates of 2.46%and 2.51%.

关键词： Predict carbon factors graph attention network prediction algorithm power grid operating parameters

The Method for Measuring Circuit Breaker Overtravel Based on Operating Process

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Instrumentation 2022年第3期9卷 37-42页

作者： HE Li XIN Xiaonan SHI Fengjie GUO Qiang LUO Danyu State Grid Institute of Technology Zhengzhou Branch ZHENGZHOU ELECTTRIC POWER COLLEGEHenan Zheng Zhou450000 Zhengzhou University 450001 yutong bus co. Ltd.Henan Zheng Zhou450000

At present,the over-travel measurement of high-voltage circuit breakers is mostly carried out after the circuit breaker is completely dismantled.The disadvantage of the measurement is that it can only be measured when the circuit breaker is dismantled and overhauled.Defects are diagnosed in a timely and effective manner,and capacity causes hidden troubles.This article provides a method for direct measurement of hydraulic circuit breakers without any adjustment or disassembly.The method can be carried out in various situations such as minor repairs,major repairs,and temporary repairs,which not only saves time,but also improves accuracy of the measurement.The comparative test results show that this method can be simple,convenient and effective to measure the overtravel of the high-voltage circuit breaker.

关键词： Circuit Breaker Stroke Over Stroke Hydraulic Mechanism Measurement

coordinated Voltage control of Distribution Network consideringMultiple Types of Electric Vehicles

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Energy Engineering 2024年第2期121卷 377-404页

作者： Liang Liu Guangda Xu Yuan Zhao Yi Lu Yu Li Jing Gao State Grid Jibei Electric Power Research Institute(North China Electric Power Research Institute co. Ltd.)Beijing100045China

The couple between the power network and the transportation network(TN)is deepening gradually with the increasing penetration rate of electric vehicles(EV),which also poses a great challenge to the traditional voltage control scheme.In this paper,we propose a coordinated voltage control strategy for the active distribution networks considering multiple types of EV.In the first stage,the action of on-load tap changer and capacitor banks,etc.,are determined by optimal power flow calculation,and the node electricity price is also determined based on dynamic time-of-use tariff mechanism.In the second stage,multiple operating scenarios of multiple types of EVs such as cabs,private cars and buses are considered,and the scheduling results of each EV are solved by building an optimization model based on constraints such as queuing theory,Floyd-Warshall algorithm and traffic flow information.In the third stage,the output power of photovoltaic and energy storage systems is fine-tuned in the normal control mode.The charging power of EVs is also regulated in the emergency control mode to reduce the voltage deviation,and the amount of regulation is calculated based on the fair voltage control mode of EVs.Finally,we test the modified IEEE 33-bus distribution system coupled with the 24-bus Beijing TN.The simulation results show that the proposed scheme can mitigate voltage violations well.

关键词： Electric vehicle transportation network voltage control queuing theory

Exploiting demand-side heterogeneous flexible resources in risk management of power system frequency

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Science China(Technological Sciences) 2024年第5期67卷 1612-1627页

作者： YAO Yu SONG YongHua YE ChengJin DING Yi ZHAO YuMing college of Electrical Engineering Zhejiang UniversityHangzhou310027China State Key Laboratory of Internet of Things for Smart City University of MacaoMacao SAR519000China Shenzhen Power Supply Bureau co. Ltd.Shenzhen518051China

More demand-side flexible resources(DFRs)are participating in the frequency regulation of renewable power systems,whose heterogeneous characteristics have a significant impact on the system frequency response.consequently,selecting suitable DFRs poses a formidable challenge for independent system operators(ISO).In this paper,a reserve allocation methodology for heterogeneous DFRs is proposed to manage the risk of power system frequency.Firstly,a performance curve is developed to describe the cost,capacity,and response speed of DFRs.Moreover,a clustering method for multiple distributed DFRs is conducted to calculate the aggregated performance curves and uncertainty coefficients.Then,the frequency security criterion considering DFRs’performance is constructed,whose linearity makes it can be easily coupled into the system scheduling model and solved.Furthermore,a risk management model for DFRs considering frequency-chance-constraint is proposed to make a trade-off between cost and frequency security.Finally,the model is transformed into mixed integer second-order cone programming(MISOCP)and solved by the commercial solver.The proposed model is validated by the IEEE 30 and IEEE 118 bus systems.

关键词： demand-side heterogenous flexible resources risk management of power system frequency performance curve aggregation method mixed integer second-order cone programming

Dispersed Wind Power Planning Method considering Network Loss correction with cold Weather

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Energy Engineering 2024年第4期121卷 1027-1048页

作者： Hanpeng Kou Tianlong Bu Leer Mao Yihong Jiao Chunming Liu Hulunbeier Power Supply company State Grid Inner Mongolia East Power Co.Ltd.Hulunbeier021100China college of Electrical and Electronic Engineering North China Electric Power UniversityBeijing102206China

In order to play a positive role of decentralised wind power on-grid for voltage stability improvement and loss reduction of distribution network,a multi-objective two-stage decentralised wind power planning method is proposed in the paper,which takes into account the network loss correction for the extreme cold region.Firstly,an electro-thermal model is introduced to reflect the effect of temperature on conductor resistance and to correct the results of active network loss calculation;secondly,a two-stage multi-objective two-stage decentralised wind power siting and capacity allocation and reactive voltage optimisation control model is constructed to take account of the network loss correction,and the multi-objective multi-planning model is established in the first stage to consider the whole-life cycle investment cost of WTGs,the system operating cost and the voltage quality of power supply,and the multi-objective planning model is established in the second stage.planning model,and the second stage further develops the reactive voltage control strategy of WTGs on this basis,and obtains the distribution network loss reduction method based on WTG siting and capacity allocation and reactive power control strategy.Finally,the optimal configuration scheme is solved by the manta ray foraging optimisation(MRFO)algorithm,and the loss of each branch line and bus loss of the distribution network before and after the adoption of this loss reduction method is calculated by taking the IEEE33 distribution system as an example,which verifies the practicability and validity of the proposed method,and provides a reference introduction for decision-making for the distributed energy planning of the distribution network.

关键词： Decentralised wind power network loss correction siting and capacity determination reactive voltage control two-stage model manta ray foraging optimisation algorithm

City-bus-Route Demand-based Efficient coupling Driving control for Parallel Plug-in Hybrid Electric bus

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Chinese Journal of Mechanical Engineering 2018年第3期31卷 168-178页

作者： Qin-Pu Wang Chao Yang Ya-Hui Liu Yuan-Bo Zhang Zhongtong bus Hold co. Ltd. State Key Laboratory of Automotive Safety and Energy Tsinghua University

Recently,plug?in hybrid electric bus has been one of the energy?e cient solutions for urban transportation. However,the current vehicle e ciency is far from optimum,because the unpredicted external driving conditions are di cult to be obtained in advance. How to further explore its fuel?saving potential under the complicated city bus driving cycles through an e cient control strategy is still a hot research issue in both academic and engineering area. To realize an e cient coupling driving operation of the hybrid powertrain,a novel coupling driving control strategy for plug?in hybrid electric bus is presented. combined with the typical feature of a city?bus?route,the fuzzy logic inference is employed to quantify the driving intention,and then to determine the coupling driving mode and the gear?shifting strategy. considering the response deviation problem in the execution layer,an adaptive robust controller for electric machine is designed to respond to the transient torque demand,and instantaneously compensate the response delay and the engine torque fluctuation. The simulations and hard?in?loop tests with the actual data of two typical driving conditions from the real?world city?bus?route are carried out,and the results demonstrate that the pro?posed method could guarantee the hybrid powertrain to track the actual torque demand with 10.4% fuel economy improvement. The optimal fuel economy can be obtained through the optimal combination of working modes. The fuel economy of plug?in hybrid electric bus can be significantly improved by the proposed control scheme without loss of drivability.

关键词： Hybrid electric vehicle Single?shaft parallel electromechanical powertrain coupling driving mode Adaptive robust control

A Loss-model-based Efficiency Optimization control Method for Induction Traction System of High-speed Train under Emergency Self-propelled Mode

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 227-239页

作者： yutong Zhu Yaohua Li Institute of Electrical Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences China Academy of Railway Sciences corporation Limited (Beijing Zongheng Electromechanical Technology co.Ltd) IEEE

Increasing attention has been paid to the efficiency improvement of the induction traction system of high-speed trains due to the high demand for energy saving. In emergency self-propelled mode, however, the dc-link voltage and the traction power of the motor are significantly reduced, resulting in decreased traction efficiency due to the low load and low speed operations. Aiming to tackle this problem, a novel efficiency improved control method is introduced to the emergency mode of high-speed train traction system in this paper. In the proposed method, a total loss model of induction motor considering the behaviors of both iron and copper loss is established. An improved iterative algorithm with decreased computational burden is then introduced, resulting in a fast solving of the optimal flux reference for loss minimization at each control period. In addition, considering the parameter variation problem due to the low load and low speed operations, a parameter estimation method is integrated to improve the controller's robustness. The effectiveness of the proposed method on efficiency improvement at low voltage and low load conditions is demonstrated by simulated and experimental results.

关键词： Rotors Stators Optimization Torque Iron Mathematical models Resistance