Review of Power Supply and Distribution Construction Technology for Highway Electromechanical Engineering

In recent years,China has made significant progress in the construction of highways,resulting in an improved highway network that has provided robust support for economic and social development.However,the rapid expansion of highway construction,power supply,and distribution has led to several challenges in mechanical and electrical engineering technology.Ensuring the safe,stable,and cost-effective operation of the power supply and distribution system to meet the diverse requirements of highway operations has become a pressing issue.This article takes an example of a highway electromechanical engineering power supply and distribution construction project to provide insight into the construction process of highway electromechanical engineering power supply and distribution technology.

Application of Control Technology Based on PLC in Power Supply and Distribution System

With the rapid development of China＇s economy, the entire social requires the safety, reliability and automation of power supply and distribution system must be improved. Therefore, extensive application of PLC technology in power supply and distribution system has great significance to ensure normal social life and production, so as to realize the entire national economy sustained and healthy development. This paper briefly introduces the PLC technology, and with practice elaborates the applications of control technology based on PLC in power supply and distribution system fi：om the reform of low-voltage distribution system, automation management and relay protection of power supply and distribution system etc.

Design and Application of Power Supply and Distribution System of Chang'e 4 Relay Satellite

A 28 V-half-regulated power bus topology and an integrated PCDU (Power Conditioning and Distribution Unit) were adopted to meet the energy demand for the Chang'e 4 relay satellite.This paper first introduces the mission features and composition of the PSDS (Power Supply and Distribution System) for the Chang'e 4 relay satellite.Due to this satellite's unusual orbit,operational mode and project restrictions,special analysis and design was conducted on the PSDS from the perspective of weight-reduction,power management,and reliability and so on.Extreme low temperature storage of SA (Solar Array) was considered and how the antenna affects the SA was analyzed.A new kind of high-specific-energy 45 Ah (Ampere-hour) battery cell was used for the first time.To make sure that the satellite would successfully pass the long shadow zones,a 100% DOD (Depth of Discharge) experiment was carried out on the battery.Since the sunlight is almost always available and there are very few times for the battery to charge or discharge,battery care to extend its lifetime is also discussed.PCDU is a device that integrates power conditioning and power distribution in one unit.The PCDU on Chang'e 4 relay satellite can output more power with less weight because of the adoption of a 28 V-half-regulated power bus topology which was also used for the first time and used lighter material for its mechanical framework.Experiment under low temperature on PCDU was conducted as well and a hot backup equalizing charge technique which is beneficial to keep performance of the battery is illustrated.The power distribution module,which is a module of PCDU,enhances the power utilization security by utilizing a static impedance measurement and build-in-test to avoid possible short circuits.As for EED (Electrical Explosive Device) module,a protection plug was specially designed and three switches with different functions were connected in series to prevent the EED from exploding by error.In addition,the allowable minimum EED bus voltage for each EED was evaluated in case of low battery voltage caused by the possible postponement of the launching time.Complete verification experiments on the ground were conducted to confirm the correctness of the design and on-orbit test data conformed to the expected results and theoretical calculation.The power supply and distribution system has been working normally since the day the Chang'e 4 relay satellite was launched into space.

Research and Application of High-Voltage Power Supply and Distribution on Launch Vehicle

High-power electric actuators are generally used on solid propellant motors,which further enhances the requirement on onboard supply voltage and output power of a launch vehicle.In this paper,combined with the electrical demand of China’s new generation solid-liquid bundled launch vehicle(LM-6 A),high-voltage battery technology,high-power switch control technology,insulation protection technology under low pressure are studied,and the key technologies and schemes are presented.The flight test of LM-6 A shows that the high-voltage power supply and distribution technology adopted is reasonable and feasible,and can be used as a reference for the designs of other launch vehicles or spacecrafts.

NOVEL AIRCRAFT ELECTRICAL POWER DISTRIBUTION SYSTEM BASED ON DISTRIBUTED COMPUTER

As a matured technique used in many fields,the distributed computer system is still a new management method for the aeronautical electrical power distribution system in our country. In this paper, a novel aircraft electrical power distribution system based on the distributed computer system is proposed. The principles, features and structure of the aircraft electrical power distribution system and the distributed computer system named electrical load management system (ELMS) are studied. The ELMS composed of four electrical load management centers (ELMCs) and two power source processors (PSPs) operates in the 1553B buses. Principles of the ELMCs and the PSPs are introduced. With the application of the distributed computer system, the aircraft electrical power distribution system is simple, adaptable and flexible.

An Algorithm for Short-Circuit Current Interval in Distribution Networks with Inverter Type Distributed Generation Based on Affine Arithmetic

During faults in a distribution network,the output power of a distributed generation(DG)may be uncertain.Moreover,the output currents of distributed power sources are also affected by the output power,resulting in uncertainties in the calculation of the short-circuit current at the time of a fault.Additionally,the impacts of such uncertainties around short-circuit currents will increase with the increase of distributed power sources.Thus,it is very important to develop a method for calculating the short-circuit current while considering the uncertainties in a distribution network.In this study,an affine arithmetic algorithm for calculating short-circuit current intervals in distribution networks with distributed power sources while considering power fluctuations is presented.The proposed algorithm includes two stages.In the first stage,normal operations are considered to establish a conservative interval affine optimization model of injection currents in distributed power sources.Constrained by the fluctuation range of distributed generation power at the moment of fault occurrence,the model can then be used to solve for the fluctuation range of injected current amplitudes in distributed power sources.The second stage is implemented after a malfunction occurs.In this stage,an affine optimization model is first established.This model is developed to characterizes the short-circuit current interval of a transmission line,and is constrained by the fluctuation range of the injected current amplitude of DG during normal operations.Finally,the range of the short-circuit current amplitudes of distribution network lines after a short-circuit fault occurs is predicted.The algorithm proposed in this article obtains an interval range containing accurate results through interval operation.Compared with traditional point value calculation methods,interval calculation methods can provide more reliable analysis and calculation results.The range of short-circuit current amplitude obtained by this algorithm is slightly larger than those obtained using the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Therefore,the proposed algorithm has good suitability and does not require iterative calculations,resulting in a significant improvement in computational speed compared to the Monte Carlo algorithm and the Latin hypercube sampling algorithm.Furthermore,the proposed algorithm can provide more reliable analysis and calculation results,improving the safety and stability of power systems.

A preventive opportunistic maintenance method for railway traction power supply system based on equipment reliability

Conventional maintenance mode for the traction power supply system(TPSS)is to perform scheduled regular maintenance activities for power supply equipment,while such maintenance mode may result in undue maintenance tasks and low efficiency due to different degradation processes of different sorts of equipment.To address this problem,this paper introduces a preventive opportunistic maintenance(POM)method for TPSS based on equipment reliability.Firstly,a POM model is established by considering the equipment reliability degradation process based on Weibull distribution.Then,by considering the total power outage time in the planned operation cycle of TPSS as the optimization objective,the optimal maintenance scheme of TPSS is formulated by iterative method of maintenance strategies.The proposed method is verified by introducing practical maintenance strategies and fault record data of the traction transformer,circuit breaker and disconnector in an actual TPSS of a railway administration.Results show that the presented method can make full use of the existing fault data to develop a POM scheme for TPSS.It can improve maintenance efficiency and reduce power outage time,providing guidance to formulate scientific maintenance strategies for TPSS.

Electrical characteristics of new three-phase traction power supply system for rail transit

A novel three-phase traction power supply system is proposed to eliminate the adverse effects caused by electric phase separation in catenary and accomplish a unifying manner of traction power supply for rail transit.With the application of two-stage three-phase continuous power supply structure,the electrical characteristics exhibit new features differing from the existing traction system.In this work,the principle for voltage levels determining two-stage network is dissected in accordance with the requirements of traction network and electric locomotive.The equivalent model of three-phase traction system is built for deducing the formula of current distribution and voltage losses.Based on the chain network model of the traction network,a simulation model is established to analyze the electrical characteristics such as traction current distribution,voltage losses,system equivalent impedance,voltage distribution,voltage unbalance and regenerative energy utilization.In a few words,quite a lot traction current of about 99%is undertaken by long-section cable network.The proportion of system voltage losses is small attributed to the two-stage three-phase power supply structure,and the voltage unbal-ance caused by impedance asymmetry of traction network is less than 1‰.In addition,the utilization rate of regenerative energy for locomotive achieves a significant promotion of over 97%.

Operation Control Method of Relay Protection in Flexible DC Distribution Network Compatible with Distributed Power Supply

A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection,leading to poor performance.The method combines a fault-tolerant fault location method based on long-term and short-term memory networks to accurately locate the fault section.Then,an operation control method for relay protection based on adaptive weight and whale optimization algorithm(WOA)is used to construct an objective function considering the shortest relay protection action time and the smallest impulse current.The adaptive weight and WOA are employed to obtain the optimal strategy for relay protection operation control,reducing the action time and impulse current.Experimental results demonstrate the effectiveness of the proposed method in accurately locating faults and improving relay protection performance.The longest operation time is reduced by 4.7023 s,and the maximum impulse current is limited to 0.3 A,effectively controlling the impact of large impulse currents and enhancing control efficiency.

Multi-converter Approach to Higher Power Density DC-DC Converter for 380 V DC Distribution System

Multi-converter approach based on the series and parallel connection topology of modular power converters has been proposed to realize higher power density DC-DC converter. The availability of the proposed approach has been verified through the design consideration and the experiment. The design consideration for two DC-DC converters has been carried out by utilizing the power converter exact loss simulator, and the design parameters to maximize their power densities have been extracted taking the trade-off between the conversion efficiency and the power density into account. The prototypes of a 2,400 W, 256-384 V boost chopper using SiC-MOSFETs and a 300 W, 32-48 V GaN-FETs boost chopper have been also developed based on the design. The SiC chopper achieved the efficiency of 97.8% and the power density of 12,8 W/cm3, and the GaN chopper accomplished 98.9% and 18.6 W/cm3 in the experiment. These results show the validity of the design and the availability of the proposed approach. The multi-converter approach enables the cost reduction of the modular power converters, and contributes to realizing the widespread use of power electronics converters in the future 380 V DC distribution system.

Parametric optimization of power system for a micro-CCHP system

The universal mathematical model of an engine is established,and an economical zone,in which an engine mainly provides medium output load at medium speed,is presented.Based on the experimental data and the universal model of such an engine above,a mathematical model of a refitted engine is provided.The boundary of the corresponding economical zone is further demarcated,and the optimal operating curve and the operating point of the engine are analyzed.Then,the energy transforming models of the power system are established in the mode of cooling,heating and power（MCHP）,the mode of heating and power（MHP）and the mode of electricity powering（MEP）.The parameter matching of the power system is optimized according to the transmission ratios of the gear box in the power distribution system.The results show that,in the MCHP,the speed transmission ratio of the engine to the gear box（ies）and the speed transmission ratio of the motor to the gear box（ims）are defined as 2.9 and 1,respectively;in the MHP,when the demand load of the power system is less than the low critical load of the economical zone,the speed transmission ratio of the motor to the engine（ime）is equal to 1,and when the demand load of the power system exceeds the low critical load of the economical zone,ime equals 0.85;in the MEP,the optimal value of ims is defined as 2.5.

A Study on the Conducted Interference of Capacitor Charging Power Supply

In this paper, a mathematical analysis of the EMI (Electromagnetic Interference) for a 20 kHz/10 kV capacitor charging power supply in frequency-domain is presented, and a related circuit model considering the transient switching interference is proposed. Due to the high working frequency and the device-switching transitions, the conducted EMI caused by the charging circuit which includes the harmonics of grid frequency, working frequency and device-switching transition frequencies. Thus under certain working situations or loads parallel power supply, the interference may cause charging failure. To solve this problem, a high frequency transformer modeled with stray capacitances and an approximation of the device-switching transition is applied in the Spice-based simulation model, and a mathematical analysis in frequency-domain is presented.

Application of Distributed Intelligent Power Supply Technology in Expressway Tunnels

With the coordinated development of today's social economy with science and technology,various advanced technologies are being used in highway engineering,especially the distributed intelligent power supply technology in expressway tunnels,which has a very significant advantage.In order to realize the effective application of this technology and promote the power supply effect in expressway tunnel,this study analyzes the advantages of this technology and its application in expressway tunnel,hoping to provide scientific reference for the application of distributed intelligent power supply technology and the engineering development of expressway tunnels.

新型电缆贯通供电系统短路特性分析

新型电缆贯通供电系统能够实现长距离输电、减少电分相数目,但两级供电模式将导致该系统结构复杂.为研究电缆贯通供电系统短路特性,首先,建立单位长度的牵引电缆和接触网-钢轨的二端口网络参数,将各个子网络级联等效成1个二端口网络,进而转化为Ⅱ型电路,实现牵引电缆和接触网-钢轨任意长度的分布参数建模;由于接触网短路后导致机车电压下降,基于车网耦合关系采用迭代计算求解短路电流电压,仿真验证计算方法的准确性.最后,解析不同短路类型的电气特性,重点分析分布电容对短路电流、电压的影响.研究结果表明:分布电容会引起短路电流增大,且在不同短路情况下均造成牵引变压器输出电压增加;接触网短路电流由两侧牵引变压器共同提供,距短路点越远提供的电流越少;电缆相间短路对非故障回路机车运行影响最大.

一种智能供配电测试设备的设计与实现

卫星供电系统测试现状是使用成熟的Agilent 34980A产品和配电器设备进行集成。针对供电测试系统集成化及智能化的测试需求,提出了一种智能供配电测试设备设计方案——集中供电监控器。它由通路继电器模块、指令发送模块、遥测状态采集模块、状态显示模块组成,具有集成度高、可靠性高、通用性强、维修性好等特点,实现了供配电测试设备的模块化、通用化、标准化、小型化,并实现了远程监控、智能监控等功能。目前已在卫星平台测试系统中得到应用,为卫星自动化测试系统起到了有力的支持作用。

基于重构级别辨识的主配协同鲁棒供电恢复方法

传统配电网供电恢复策略大多先进行孤岛划分、后进行动态重构,缺少对二者的共同考虑,而全局重构又存在经济性差、操作难度大等问题。为此,提出基于重构级别辨识的主配协同鲁棒供电恢复方法。首先,根据配电系统的故障情况,按照局部自治、低级别优先重构的原则,快速确定主(变电站层级)、配(配电线路层级)多级重构需求。然后,对不同级别的区域进行孤岛划分与重构。接着,针对描述分布式光伏出力不确定性的凸包多面体集合存在放缩过程中保守性大的问题,采用超平面方法切割凸包集合并建立改进凸包集合模型。进一步,构建了配电网鲁棒供电恢复模型,并采用列与约束生成算法对鲁棒供电恢复模型进行求解。最后,通过改进的78节点系统进行仿真验证。结果表明,基于重构级别辨识的主配协同鲁棒供电恢复方法可以降低保守性,提高供电恢复结果的鲁棒性。

Power-One通信电源监控系统通信协议破解

根据数据链路层通信协议的一般格式,对串口监听工具截取的Power-One通信电源监控系统的通信信息进行了逻辑推理和分析,破解了其通信协议的格式和各种通信命令。实际验证表明,破解结果正确无误。研究结果对于我国通信电源分布式监控系统通信协议的设计和实现,具有一定的借鉴意义。

基于5G的分布式电源优化调度研究

随着分布式电源的大规模接入,传统电力系统面临着调度优化的巨大挑战。基于此,提出一种基于5G的分布式电源优化调度方法,充分利用5G的高速率、低时延、广连接特性,实现了分布式电源的高效监控和智能调度。该方法包括基于物联网的数据采集、5G通信数据传输、基于机器学习的电源状态评估以及多智能体协作的优化调度这4个环节。该研究为解决分布式电源调度问题提供了新的技术路径。

配电自动化终端设备在电力配网自动化中的应用

本研究探讨了配电自动化终端设备在电力配网自动化中的应用,主要包括配电终端单元(Distributed Terminal Unit,DTU)、馈线终端单元(Feeder Terminal Unit,FTU)和变电站终端单元(Transformer Terminal Unit,TTU)的功能与技术原理。这些设备通过实时监测、故障定位与自动隔离,实现了配网的智能化管理。研究表明,配电自动化终端设备对提升电网运行效率、缩短停电时间具有重要意义。

基于Gabor变换的电力通信电源分布式监控方法

电力通信电源信号具有非平稳的特性,导致对其监控输出的信号在分布上难以实现有效收敛,因此提出基于Gabor变换的电力通信电源分布式监控方法。选择高灵敏度、宽频带的传感器捕获电力通信数据,基于数据采集卡将传感器输出的模拟信号转换为数字信号,通过执行嵌入的Gabor变换和滤波器组处理,监控提取关键时频信息。利用Gabor变换处理电力通信电源信号,根据信号的时频分布特性,基于改进的香农熵值量化其时频聚集度。在测试结果中,监控输出的信号在分布上能够有效收敛,具有良好的监控效果。