Research of Pure Electric Ferry System and Its Short-Circuit Protection and Calculation

System control and safety reliability are important links of the marine DC (Direct Current) power system. The simulationmodel is built by Matlab/Simulink, the battery and super-capacitor are supplied to the system through a three-phase interleaved DC/DCconverter, the fuse and disconnector switch combination are used as the protection device, and the short-circuit point is set betweeneach branch and the DC distribution board, performing short-circuit simulation. This paper also proposes a short-circuit calculationmethod for super-capacitors based on the simplified model of series RC (Resistors & Capacitors), and verifies its correctness throughsimulation data. The results show that the introduction of a three-phase interleaved DC/DC converter reduces the current ripple andmakes the system control more convenient;short-circuit calculation and simulation have determined the short-circuit withstandcapability of the DC distribution board, and verified the feasibility of the fuse selection method and the short-circuit calculation methodof the super-capacitor. This provides reliable verification for the application and calculation of the actual project.

Mode switching torque distribution strategy of timely four-wheel driven high-gap plant protection machine

The high-gap plant protection machine is taken in this paper as the research object to ensure the good driving power and safety of the high-gap plant protection machine,and the control strategy of inter-shaft torque distribution is established under different working conditions to improve vehicle power and lateral stability.The anticipated demand torque is initially determined based on the structural characteristics and operational principles of the plant protection machine.Subsequently,a hierarchical control framework is devised by incorporating a formulated switching control strategy.Finally,a simulation model for torque distribution control strategy between shafts is developed on the Matlab/Simulink platform,followed by simulation and experimental verification.The results are presented as follows:the inter-shaft torque distribution strategy established in this paper increases the average longitudinal acceleration by 0.13 m/s^(2) and 0.14 m/s^(2) under the control of low and high to low adhesion road surfaces,respectively.Under the control of the single-line shifting condition,the yaw velocity can successfully follow the expected value with a maximum value of 0.61 rad/s.The side deflection angle of the center of mass does not exceed 2.8°,which can follow the ideal trajectory and improve power and safety.

Protection of Low Voltage CIGRE Distribution Network

High quality electricity services are the prime objectives in the modern power systems around the world. One of the main players to achieve this is the protection of the system which needs to be fast, reliable and cost effective. The study about the protection of the Low Voltage (LV) CIGRE distribution grid and networks like this has been proposed in this paper. The main objective of this paper is to develop protection against short circuit faults which might appear anywhere in the network. The protection of the power networks that comprises of renewable energy generation units is complicated because of the bidirectional flow of the current and is a challenge for the protection engineers. The selection of the protection devices in this paper is made to protect the network against faults in grid connected and island mode of operation. Ultra-fast fuses are proposed in order to protect the inverters used for Photovoltaic (PV) and battery applications. The disconnection of the PV solar panels when in island mode is made by proposing switch disconnecting devices. ABB is currently using these kinds of disconnection devices for the purpose of protecting solar panels against over voltages in the case of islanding. The over speed protection of the existing Wind Turbine Generator (WTG) in the CIGRE network in case of grid loss is also proposed in this paper.

Active dynamic pre-protection mechanism for MPLS-TP network

The active-fault-alarm （AFA） technologies and the dynamic protection mechanism of the optical network controlled by the multi-protocol label switching transport profile （MPLS-TP） are both studied in this article. On this basis, an active dynamic pre-protection （ADPP） mechanism is proposed. This active dynamic pre-protection mechanism is allowed to establish a so called temporary protection path （TPP） for the work path before a potential fault occurs and to switch to TPP only after the fault occurs. It keeps the TPP flexibly only when it is in low- quality or fault state to realize dynamic protection even better and to achieve better resource utilization. Simulation results show that the proposed new mechanism has better performance in terms of the flexibility and the efficiency from the perspective of time.

Integrated dynamic shared protection algorithm for GMPLS networks

The path protection approach is widely investigated as a survivability solution for GMPLS networks, which has the advantage of efficient capacity utilization. However, there is a problem of the path protection approach that searching a disjoint backup path for a primary path is often unsuccessful. In order to resolve this problem, an integrated dynamic shared protection （IDSP） algorithm is proposed. The main idea of the proposed algorithm is that the path protection approach is first used to establish a backup path for the primary path; if the establishment is unsuccessful, then the primary path is dynamically divided into segments whose hop count are not fixed but not more than the limitation calculated by the equations introduced. In this proposal, backup bandwidth sharing is allowed to improve the capacity utilization ratio, which makes the link cost function quite different from previous ones. Simulation experiments are presented to demonstrate the efficiency of the proposed method compared with previous methods. Numerical results show that IDSP can not only achieve low protection failure probability but can also gain a better tradeoff between the protection overbuild and the average recovery time.

Dynamic shared segment protection algorithm with differentiated reliability in GMPLS networks

To improve the resource utilization ratio and shorten the recovery time of the shared path protection with differentiated reliability （SPP-DiR） algorithm, an algorithm called dynamic shared segment protection with differentiated reliability （DSSP-DiR） is proposed for survivable GMPLS networks. In the proposed algorithm, a primary path is dynamically divided into several segments according to the differentiated reliability requirements of the customers. In the SPP-DiR algorithm, the whole primary path should be protected, while in the DSSP- DiR algorithm, only partial segments on the primary path need to be protected, which can reduce more backup bandwidths than that in the SPP-DiR algorithm. Simulation results show that the DSSP-DiR algorithm achieves higher resource utilization ratio, lower protection failure probability, and shorter recovery time than the SPP-DiR algorithm.

具有切换特性和免疫控制的计算机病毒传播模型

针对目前计算机病毒传播建模研究中没有综合考虑安全防护以及病毒持续更新的影响,提出具有切换特性和免疫控制的计算机病毒SEIR(Susceptible-Exposed-Infected-Recovery)传播模型。考虑安全防护措施和病毒更新的影响,构建切换型病毒传播模型,该模型由低防护子系统和高防护子系统构成。考虑免疫控制策略,构建切换脉冲型病毒传播模型。为验证模型的有效性,分别在BA无标度网络和SW小世界网络进行数值仿真,并且进行对比分析。实验结果表明:在SW小世界网络中免疫控制策略更能有效控制病毒的传播;低防护传播期与高防护传播期的比值越小,达到平稳时潜伏节点和感染节点的密度越小;病毒的更新周期越长,潜伏节点和感染节点的峰值密度越低。

励磁系统交流侧接地对转子接地保护的影响

励磁系统交流侧接地将引起注入式转子接地保护、乒乓切换式转子接地保护误动作。本文介绍了一起相关案例,并对引起误动的基本原理进行了深入分析和定量计算,总结了励磁系统交流侧接地引起采样数据变化的典型特征,提出了关于缩小转子接地保护定位范围的思考。当转子一点接地保护动作后,应首先根据采样数据的变化,对故障点位于励磁系统交流侧还是直流侧做出初步判断,缩小故障定位范围,为快速查找故障提供决策依据。

矿用隔爆高压配电装置保护及控制电源设计

针对目前井下矿用隔爆高压配电装置保护及控制电源与供电系统同源存在的问题进行分析,提出了矿用独立电源供电的方式。对矿用隔爆高压配电装置保护及控制供电方式进行了分析与设计;对矿用隔爆高压配电装置用独立电源进行了设计;对矿用隔爆高压配电装置保护控制供电方式进行了研究,进一步对其进行了保护控制供电设计和电源切换装置设计。实现了保护及控制供电一用一备独立供电,保障供电系统的安全运行。目前该供电方式已经在潞安化工集团、晋能控股集团的大型矿井实现了井下应用。

基于SDN和集成学习的工业控制网络安全防护系统

针对工业控制网络通信信息安全与稳定问题,设计一种基于SDN和集成学习的工业控制网络安全防护系统。该系统采用SDN技术,分为物理层、现场层、转发层、控制层和应用层等5个层次。物理层包含现场终端设备;现场层通过控制模块与操作员站实现对现场终端的控制;转发层使用SDN交换机进行通信数据传输,并将数据镜像传输至应用层进行安全分析;控制层中的SDN控制器管理和控制SDN交换机,并执行应用层下发的安全防护策略;应用层利用集成学习算法对工业控制网络进行入侵行为检测,通过安全响应模块分析入侵信息并选择相应的防御机制。实验结果表明,所设计系统满足工业控制网络通信的实时性要求,能准确地实施入侵检测,从而保障工业控制网络的安全性和正常通信。

继电保护测试仪自动检测系统设计

继电保护测试仪是对继电保护装置调试和检验的重要仪器。为了进一步提高继电保护测试仪的检测精度、稳定性和检测效率,设计了基于LabVIEW的继电保护测试仪自动检测系统。该系统采用LabVIEW模块化的编程思想,实现继电保护测试仪的自动检测、手动检测、保存报告等功能。为了解决继电保护测试仪的输出为三相,而万用表和示波器仅支持单相测试的问题,设计了输出转换装置。基于转换装置,可以在测试开始前一次性完成所有接线,并在测试过程中根据不同校准项目进行测试回路自动切换。功能测试结果表明,该系统能满足检验标准化、报告标准化和闭环自动测试要求。该系统对其他二次测量设备的自动检测校准有一定的借鉴意义。

矿井提升机控制系统的完善及改进

针对现用矿井提升机控制系统在日常运行过程中存在的磁性开关误动作、安全保护触发条件不全及保护动作条件不合理等问题,设计并完善相关控制工艺及程序,使提升机安全保护的监测更加全面,动作更加灵敏、可靠,进而确保提升机的安全、稳定运行。

HL-3聚变用大容量Crowbar

[目的]面向HL-3聚变大科学装置极端故障能量快速转移,配置短路保护用大容量旁路开关需求。[方法]基于HL-3磁体电源参数,结合电力电子变流技术及可控硅触发应用基础,针对快速冲击应用中多并联可控硅一致性导通及稳定均流的严苛工况,融合电力电子变流工程实践经验,经并联分支导电线路等长型式改良;并联元件参数一致性筛选,并联臂内元件位置与参数差异化选配;通过在可控硅侧附加串联电阻物理强迫均流,并对附加电阻热稳定性核算,并联桥臂电动力冲击验算;可控硅元件高频脉冲列强触发等手段和方法。[结果]推导设计了一种稳定的可控硅220 kA级大容量聚变用crowbar旁路保护电子开关系统,经试验模拟实测验证及实载160 kA冲击考验,实现了HL-3保护用大容量旁路开关的匹配要求。[结论]在做好热动、稳定性验算的基础上,采用线路改良,附加物理强迫均流,元件参数筛选及装配,触发模式调整等综合手段,实现大容量crowbar在聚变中的配套应用是完全可行的。

新型电力系统下低压直流配网的接地故障保护方法

电力系统低碳转型,构建安全高效和灵活可靠的配电网为基础的新型电力系统将对我国“碳达峰、碳中和”目标的实现起到关键作用。文中以低压直流(low voltage direct current,LVDC)配网系统为研究对象,针对配电网低压侧的接地故障问题,提出了一种采用IGBT构造投切旁路的人体保护方法。文中建立接地故障等效模型并进行理论分析,通过故障阈值识别判据产生保护人体的投切旁路信号,并对不同类型的接地故障进行区分,考虑多支路故障情况对旁路投切保护判据的影响,将故障值范围进行划分,进一步提出了旁路投切的分级保护方案,搭建实物模型对保护方法进行验证。实验结果表明所提保护方法能保护人体安全,具有灵敏性好,安全可控的优点,能显著提高配网系统的运行稳定性。

一起接地开关故障引起两座变电站跳闸的事故分析

本文介绍一起由接地开关故障引起两座变电站断路器越级跳闸的事故,通过现场勘察并结合保护装置报文、故障录波进行分析,找出跳闸原因并提出整改建议。

铁路道岔除雪方式对比分析及安全卡控措施

铁路安全易受天气因素影响,如遇高强度降雪、除雪工作不到位时,极易造成列车运行中断,对铁路运输生产效益及行车安全造成重大影响。铁路道岔除雪是冬季除雪作业中的重要环节,立足现场实际选取合理的除雪方式、制定可行的除雪方案是除雪工作的重中之重,除雪方式的选用直接关系到除雪效率,同时除雪过程中安全卡控也尤为重要。从吹雪、融雪、扫雪3种除雪方式出发,对国内外现行道岔除雪方式进行对比分析,并以朔黄铁路公司除雪工作为例进行剖析,结合实际除雪工作经验,对现行除雪方式进行优化探讨。

一种工业退火炉保护气切换控制策略的优化

某工业退火炉保护气切换控制由于其炉况特性,其温度数据传输极易造成滞后或中断,而温度数据是切换控制条件的重要组成部分,原DCS系统中的切换控制策略对此也缺乏应对措施,这将极易造成误切换。针对工业退火炉保护气切换控制存在的上述问题,对保护气切换策略进行了优化,通过新增计时器模块,对控制炉段前的工艺控制情况计时,并将计时器模块的输出状态引入到新的切换控制策略中,自动判断切换工艺条件,有效提高了退火炉保护气切换稳定性,取得了较好的控制效果。

燃机用国产发电机断路器的研究与应用

燃机用发电机断路器是电力行业的核心设备,其国产化水平的提高对于电力行业的发展具有重要意义。介绍了燃机用国产发电机断路器的研究及应用情况,对燃机用发电机断路器成套装置的结构特点做了详细阐述,同时对首台套国产设备的应用情况做了介绍。通过燃机用发电机断路器成套装置的工程应用,带动相关产业链的发展,提高了燃机发电成套装置的国产化率。

卫星导航抗干扰射频单板自动化测试系统 设计与实现

针对卫星导航抗干扰射频单板人工测试过程较复杂且难以快速批量测试的问题,提出了基于C#与STM32的卫星导航抗干扰射频单板自动化测试系统。首先,通过自动化测试软件与STM32主控制器数据通信控制射频开关电路进行数据采集,然后将采集数据与多次人工测试结果对比分析,形成多项校准参数并应用于测试系统,最后通过批量测试验证系统测试结果准确性。通过批量试验数据证明各项测量指标误差均小于2.5%,测试效率较人工测试提升至少3.3倍,具有较高测量精度和效率。同时,该自动化测试系统对测试单板有过压过流保护功能,能有效保护被测单板不被损坏,综合整体性能具有良好的应用前景。

宽输入电压大功率双路矿用本安电源的设计

针对现有矿用本安电源体积大、效率低的问题,提出了应用氮化镓合封开关电源芯片设计的反激式开关型矿用本安电源。将AC 85~250 V输入转换为DC 12.5 V、2.5 A两路本安输出,使功率密度增加一倍。测试结果表明,这款本安电源输出稳定、效率高、纹波小,输出参数满足本安要求。