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.

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.

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.

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 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.

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.

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.

Considerations of Electricity Supply Quality in Spain

The quality of supply in Spain is regulated by Act 54/1997 as the basic standard and further developed by Royal Decree 1955/2000, among others. Also this law （1997） introduces the division between generators, distribution companies and retailers. The aim of this paper is to provide an overview of the fundamental parameters to be taken into account when examining the status of national regulations in Spain on the quality of electricity supply, in addition to describing the various agents intervening in these. There are two more aspects to consider： the guarantee of supply and energy is provided at the lowest cost to consumers. The authors propose to include phase-shifting transformers at specific strategic points, in accordance with power flow control principles in parallel circuits. Finally, it can be concluded that Royal Decree 222/2008 needs reviewing and applying effectively, as do modifications to Royal Decree 1995/2000 providing remuneration that effectively induces electricity companies to invest in their networks, and ends with ＂a well-paid electricity company is obliged to invest in network improvements＂.

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.

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。

欧洲固体氧化物燃料电池(SOFC)产业化现状

固体氧化物燃料电池(SOFC)具有燃料适用范围广、能量转换效率高(发电效率40%~60%,综合能效≥80%)、全固态结构、模块化组装、零污染等优点,作为固定式或分布式发电可增强电网清洁供电的能力、安全性、可靠性和稳定性.SOFC具有多种不同的结构,其发电规模覆盖几十瓦至百兆瓦,可根据不同的应用场景选择不同的结构,应用场景主要包括固定式发电、分布式供电、热(冷)电联供、交通车辆辅助动力电源等领域.国内的SOFC技术发展较晚,目前已取得一定的研究进展,并且能够自主研发出十几千瓦的SOFC发电系统,但与国际领先水平还有很大的差距,主要体现在输出功率、生产成本及使用寿命等方面.欧洲的SOFC技术处于国际领先水平,具有一批成功实现产品化的公司,通过对其技术和产品的调研,可深入的了解欧洲SOFC技术现状和发展趋势,为国内SOFC技术的发展提供借鉴作用.

A Model Predictive Scheduling Algorithm inReal-Time Control Systems

Abstract-The ineffective utilization of power resources has attracted much attention in current years. This paper proposes a real-time distributed load scheduling algorithm considering constraints of power supply. Firstly, an objective function is designed based on the constraint, and a base load forecasting model is established when aggregating renewable generation and non-deferrable load into a power system, which aims to transform the problem of deferrable loads scheduling into a distributed optimal control problem. Then, to optimize the objective function, a real-time scheduling algorithm is presented to solve the proposed control problem. At every time step, the purpose is to minimize the variance of differences between power supply and aggregate load, which can thus ensure the effective utilization of power resources. Finally, simulation examples are provided to illustrate the effectiveness of the proposed algorithm.

A diagnostic method for distribution networks based on power supply safety standards

In order to overcome the shortages of diagnostic method for distribution networks considering the reliability assessment,this paper proposed a method based on power supply safety standards.It profoundly analyzed the security standard of supply for urban power networks,and established quantitative indicators of load groups based on different fault conditions.Then a method suitable for diagnostic evaluation of urban distribution networks in China was given.In the method,“N-1”calibration analysis of the distribution network was conducted.Then the results are compared with quantitative indicators of load groups on different conditions deriving the diagnostic conclusions and the standard revision is discussed.The feasibility and accuracy of the method is finally verified in the case study.

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。

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.