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.

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.

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.

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.

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.

一种高效星载功率调节与配电单元设计与实现

文章结合深空探测供配电分系统任务特点,提出功率调节、配电、火工控制等多功能模块轻小型一体化设计的必要性。介绍了国外功率调节与配电单元的研究现状、国产功率调节与配电单元研制的意义,功率调节与配电单元组成及功能设计,并通过多母线融合设计、多路放电均流设计、单元集成化设计等关键技术,解决了深空探测器高可靠轻小型化功率调节与配电单元设计难题。在轨飞行结果表明:功率调节与配电单元功能正常,工作可靠,性能优良。功率调节与配电单元的国产化设计实现,可为其它航天器的设计提供参考和借鉴。

一种面向运载火箭电气系统的模块化分级供配电体制

针对运载火箭电气系统供电电缆规模偏大、拓扑复杂、易引发跨级供电潜通路等问题,提出了一种电气系统模块化分级供配电方案。将运载火箭各级分别规划为一个独立的供配电单元,供配电单元内采用通用化设计,实现对内部负载的一体化供电;供配电单元间、电气系统箭地间、供电母线间电气隔离,以避免供配电单元间的电气耦合,彻底消除级间潜通路,降低设计难度,最终使得运载火箭电气系统供配电体制具备系统层级模块化特征和供配电单元即插即用能力,为未来电气系统供配电架构的标准化设计和运载火箭分级测试提供技术基础。

基于RPC的光储接入牵引供电系统协调控制方法

为将光伏发电接入牵引供电系统进行有效利用,同时兼顾牵引供电系统电能质量改善及列车再生制动能量回收利用,提出了一种基于铁路功率调节器的光储系统接入牵引供电系统的协调控制方法.首先,搭建基于铁路功率调节器的光储系统接入牵引供电拓扑结构,并对其电能质量补偿机理进行理论分析;在此基础上,充分考虑光储系统的运行条件以及列车牵引、制动、空载或惰行工况,提出光储系统接入牵引供电的联合协调控制方法,实现了“光+储+荷”三者间的协调控制、牵引供电系统负序的动态补偿以及谐波的有效抑制;在RT-Lab实时仿真系统中建立了基于铁路功率调节器的光伏接入牵引供电系统仿真模型,并结合实际光照和牵引工况数据验证本文所提出的系统结构以及协调控制方法的有效性.结果表明:本文所提出的系统结构以及协调控制方法能够实现牵引供电系统中光储系统的有效接入,再生制动能量回收率提升至86.7%,功率因数提升6.4%,对谐波特别是高次谐波含有率有较大改善,满足光伏电能高效消纳及综合利用、电能质量动态综合补偿、再生制动能量回收多重需求.

故障关联矩阵下弹性配电网可靠性评估

配电网弹性是指系统受到干扰后恢复原有状态的能力,而自然灾害的频发要求配电网不仅在正常条件下能够可靠运行,而且还能够在极端灾害出现时保持必要能力。据此,提出一种基于故障关联矩阵(fault incidence matrix,FIM)的弹性配电网可靠性评价方法。通过建立FIM,使用简化的矩阵代数、布尔运算即可实现配电系统可靠性、弹性和供电能力的显式解析计算,避免了评估过程中故障枚举的重复性搜索工作,节省了计算时间,并且可适用于结构复杂的配电网,易于扩展。最后结果表明:采用文中方法的计算时间仅为约0.055 s,相较于故障扩散算法和分块算法分别减少87%和75%的时间。

集中式馈线自动化配电网供电可靠性评估

计及集中式馈线自动化的配电网可靠性评估尚存在较多研究空白,且多数研究仅计及故障停电的影响,在考虑预安排检修容量约束的情况下,计及负荷转供影响,结合馈线自动化的类型及运行逻辑,依据馈线自动化相关技术指标,对恢复供电过程中出现的负荷点进行详细分类,推导出不同类型负荷期望恢复供电时间和配电网供电可靠性指标计算公式。结合算例进行分析可知,不同终端配置下馈线系统平均停电持续时间SAIDI可减少0.95~1.08 h/(用户·a),说明了优化终端配置可有效提高配电网供电可靠性,证明了所提评估方法的准确性和实用性,并比较了不同终端配置对可靠性的影响。

国家区域医疗中心武汉协和重庆医院电气设计要点

以国家区域医疗中心华中科技大学同济医学院附属协和医院重庆医院(一期工程)为例,对医疗建筑电气设计的以下问题进行分析与探讨:供配电系统设计的变压器安装容量合理性分析、供配电系统可靠性分析、变压器能效等级选择及机房选址等;针对医疗建筑的电能质量问题提出解决方案;调研同类医疗项目存在的照明光环境问题,设计本项目的物联网智能照明光环境系统;总结本项目光储直柔微网系统设计要点。

供配电技术课程思政项目化重构

为了实现职业教育高素质高技能的人才培养目标,阐述了供配电技术课程思政项目化教学内容的重构:一方面,将学科导向的教学内容重构,设计出以产业需求为导向的、融入电力行业现行国标规范的项目化知识结构,实现“技”的培养;另一方面,在项目化教学内容中,深入挖掘并有机融入思政元素,实现“德”的培养。供配电技术课程思政项目化,实现了在职业教育教学过程中传授知识技能、孕育意识形态,凸显了职院校“德技并修”的人才培养目标。

基于动态阈值分割法的接触轨图像关键特征点提取方法研究

在地铁系统中,接触轨的状态对于牵引供电系统的安全性至关重要,一旦接触轨几何参数超出正常范围,不仅会导致集电靴无法正常取流,进而影响运营车辆的顺畅运行,而且在极端情况下,还可能引发严重的安全事故。传统的接触轨几何参数测量方法在采集图像时通常面临背景复杂、干扰图像多等问题,以致检测数据量少、检测密度低,从而难以精确提取接触轨的关键特征信息。针对这一问题,文章提出一种新的方法,即结合动态阈值分割法、直线拟合以及投影计算的方式,有效解决接触轨特征点提取的难点,实现几何参数的精确测量。该方法不仅能够准确捕捉到接触轨的细微变化,还能够确保测量结果的可靠性和准确性。为进一步提高测量的便捷性和实用性,研究过程中同步研制出一套接触轨几何参数的便携式测量装置,并在地铁线路上进行现场应用示范,为实际运营中的接触轨状态监测提供有力的技术支持。

广州地铁22号线交流牵引供电系统电磁干扰问题分析

[目的]当地铁线路正常运行时,由于钢轨对地不能做到完全绝缘,采用交流牵引供电系统的地铁会对邻近金属油气管道产生交流干扰。因此,有必要研究地铁交流牵引供电系统对外部电磁干扰的问题。[方法]以广州某金属油气管道与广州地铁22号线并行段为例,建立地铁隧道与金属油气管道耦合模型,对金属油气管道进行电磁干扰仿真分析;计算了与隧道呈不同夹角的油气管道各段的电磁感应电压、地电位和涂层耐受电压,分析了电磁干扰的主要影响因素。[结果及结论]交流牵引供电制式下,管道涂层实际承受电压为涂层内部金属管道表面的电压和外部土壤中的地电位的差值,地铁隧道在金属管道表面产生的感应电压幅值是土壤地电位幅值的10倍以上,金属油气管道受到的电磁干扰以管道与地铁的电磁感应电压为主;金属油气管道及地铁隧道并行段是产生电磁干扰的主要区段;增加回流线可以极大地降低金属油气管道的电磁感应电压,回流线的位置与数量对减少电磁干扰效果有极大的影响。

含高比例分布式电源配电网分布式供电恢复方法

针对高比例分布式电源(DG)接入配电网,现有供电恢复方法未充分考虑DG故障穿越特性。文中提出了基于分布式控制的配电网多阶段供电恢复方法,以充分利用DG的电网支撑能力。分析了DG故障穿越特性及其电网支撑能力,并基于高比例DG接入后配电网不同运行方式,提出了负荷容量估算方法和DG分类处理策略。建立了分布式控制的供电恢复模型,并基于联络线路容量裕度指标提出多联络路径选择策略。最后,提出了适应高比例DG接入配电网的多阶段供电恢复方案。所提方法可以更好地发挥DG支撑作用,提高快速供电恢复能力。仿真算例验证了所提方法的有效性。

考虑合环延时的含分布式电源配电网合环电流协同控制方法

合环操作常用于配电网故障恢复中,但在合环过程中产生的冲击电流可能导致线路电流越限,不仅可能损坏设备,还会危害人身安全。针对合环电流的抑制大多关注于整体优化,未重视合环暂态过程产生的冲击电流问题,本文提出了一种考虑合环延时与分布式电源(DG)控制协同抑制合环冲击电流的方法。通过分析配电网合环冲击电流的产生过程及原理,刻画了DG出力以及合环延时对于合环冲击电流的影响,建立了DG主动控制与合环协同的控制优化模型,从而提出了考虑合环延时影响以及DG出力的配电网合环冲击电流协同控制方法。算例表明,该方法通过DG出力与预期合环时刻的优化,能够最大程度上控制配电网合环过程中的冲击电流,提升了配电系统的安全性。