Variants of Secondary Control with Power Recovery for Loading Hydraulic Driving Device

Current high power load simulators are generally incapable of obtaining both high loading performance and high energy efficiency. Simulators with high energy efficiency are used to simulate static-state load, and those with high dynamic performance typically have low energy efficiency. In this paper, the variants of secondary control（VSC） with power recovery are developed to solve this problem for loading hydraulic driving devices that operate under variable pressure, unlike classical secondary control（CSC） that operates in constant pressure network. Hydrostatic secondary control units are used as the loading components, by which the absorbed mechanical power from the tested device is converted into hydraulic power and then fed back into the tested system through 4 types of feedback passages（FPs）. The loading subsystem can operate in constant pressure network, controlled variable pressure network, or the same variable pressure network as that of the tested device by using different FPs. The 4 types of systems are defined, and their key techniques are analyzed, including work principle, simulating the work state of original tested device, static operation points, loading performance, energy efficiency, and control strategy, etc. The important technical merits of the 4 schemes are compared, and 3 of the schemes are selected, designed, simulated using AMESim and evaluated. The researching results show that the investigated systems can simulate the given loads effectively, realize the work conditions of the tested device, and furthermore attain a high power recovery efficiency that ranges from 0.54 to 0.85, even though the 3 schemes have different loading performances and energy efficiencies. This paper proposes several loading schemes that can achieve both high dynamic performance and high power recovery efficiency.

Applications of Secondary Electron Composition Contrast Imaging Method in Microstructure Studies on Heterojunction Semiconductor Devices and Multilayer Materials

The principle, imaging condition and experimental method for obtaining high resolution composition contrast in secondary electron image were described. A new technique of specimen preparation for secondary electron composition contrast observation was introduced and discussed. By using multilayer P+Si1-xGex/pSi heterojunction internal photoemission infrared detector as an example, the applications of secondary electron composition contrast imaging in microstructure studies on heterojunction semiconducting materials and devices were stated. The characteristics of the image were compared with the ordinary transmission electron diffraction contrast image. The prospects of applications of the imaging method in heterojunction semiconductor devices and multilayer materials are also discussed.

A Smart Substation Field Secondary Device Testing Technique Based on Recurrence Principle

According to the demand of substation secondary device dynamic performance testing, a smart substation field testing technique based on recurrence principle is proposed in the paper, and the characteristics of smart substation secondary device digitization and information sharing are used by the technique. The principle of testing technique is as follow: the digital simulation model is constructed on the basis of the substation’s actual construction, then the simulating data highly similar to substation’s actual electric quantity transient process is generated, at last, the substation digital secondary device can be tested by using data “recurrence” technique. The testing technique is verified and applied by constructing testing system, the application results show that the technique can effectively perform field test on the dynamic performance of digital secondary device, and the technique has good engineering implementation and application value.

Rapid Modeling of an Excavator Working Device Based on the Secondary Development of Pro/E

In order to shorten the design cycle of the excavator working device, we have proposed a rapid modeling method for the excavator working device which uses parameters. Based on the Pro/toolkit, which is secondary development tool of Pro/E4.0,and combined with Vs C＋＋2005 programming software. It developed a flexible set of MFC visualization-friendly interfaces. Users can enter data in the visual interface according to their needs and it will generate a new part model quickly. So it improves the design quality, shortens the design cycle, and makes the cost lower significantly.

Investigation on the Oscillating Buoy Wave Power Device

An oscillating buoy wave power device (OD) is a device extracting wave power by an oscillating buoy. Being excited by waves, the buoy heaves up and down to convert wave energy into electricity by means of a mechanical or hydraulic device. Compared with an Oscillating Water Column (OWC) wave power device, the OD has the same capture width ratio as the OWC does, but much higher secondary conversion efficiency. Moreover, the chamber of the OWC, which is the most expensive and difficult part to be built, is not necessary for the OD, so it is easier to construct an OD. In this paper, a numerical calculation is conducted for an optimal design of the OD firstly, then a model of the device is built and, a model test is carried out in a wave tank. The results show that the total efficiency of the OD is much higher than that of the OWC and that the OD is a promising wave power device.

Reliability analysis for vertical integration of protection,measurement,merge unit,and intelligent terminal device

The reliability analysis of vertically integrated protection devices is crucial for designing International Electrotechnical Commission(IEC)61850-based substations.This paper presents the hardware architecture of a four-inone vertically integrated device and the information transmission path of each function based on the functional information transmission chain of protection devices,measurement and control devices,merging units,and intelligent terminals.Additionally,a reliability analysis model of the protection device and its protection system is constructed using the fault tree analysis method while considering the characteristics of each module of the vertically integrated device.The stability probability of the protection system in each state is analyzed by combining the state-transfer equations of line and busbar protection with a Markov chain.Finally,the failure rate and availability of the protection device and its protection system are calculated under different ambient temperatures using a 110 kV intelligent substation as an example.The sensitivity of each device module is analyzed.

Effect of Cu doping on the secondary electron yield of carbon films on Ag-plated aluminum alloy

Reducing the secondary electron yield(SEY)of Ag-plated aluminum alloy is important for high-power microwave components.In this work,Cu doped carbon films are prepared and the secondary electron emission characteristics are studied systematically.The secondary electron coefficientδ_(max) of carbon films increases with the Cu contents increasing at first,and then decreases to 1.53 at a high doping ratio of 0.645.From the viewpoint of surface structure,the higher the content of Cu is,the rougher the surface is,since more cluster particles appear on the surface due to the small solid solubility of Cu in the amorphous carbon network.However,from viewpoint of the electronic structure,the reduction of the sp2 hybrid bonds will increase the SEY effect as the content of Cu increases,due to the decreasing probability of collision with free electrons.Thus,the two mechanisms would compete and coexist to affect the SEY characteristics in Cu doped carbon films.

短路电流对二次设备电磁干扰分析及抗干扰措施

目前智能配电网的建设不断推进,加快了配电开关一二次设备相关技术的发展,也对长期处于复杂电磁环境下的二次设备提出了更高的要求。文中基于合成试验回路搭建了短路电流对配电开关二次设备电磁干扰试验平台,开展开断故障电流对相关干扰对成套设备的影响研究,分析干扰信号产生原因、频谱特性。针对干扰的特性设计一套抗干扰测量系统,利用ATP-EMTP模拟合成回路进行仿真分析并进行实际测试验证。结果表明:成套设备进行开断试验时,二次设备端口会受到较大的干扰。电流波形也会发生畸变,干扰电流的最高可到26 A,且干扰电流受电流互感器磁饱和和退饱和的影响,通过增加抗干扰措施,二次设备输出准确度与之相比提升约40%。本次的试验结果可为一二次融合成套设备中二次设备电磁兼容研究提供相关依据。

基于关系超图增强Transformer的智能站二次设备故障诊断研究

随着智能变电站二次设备的状态感知与自描述能力不断提升,在提高电网调控细粒度的同时,其海量、驳杂、离散的状态信息也使故障诊断难度倍增。为提高二次设备故障诊断精度与效率,提出基于关系超图增强Transformer的二次设备故障诊断算法。首先利用Apriori算法挖掘故障信号间的关联规则,构建关系超图。然后利用超图卷积神经网络(hypergraph convolutional neural network,HGCN)和微调标准Transformer网络学习故障特征间的高阶关系和上下文表达,再经过误差反向传播、非线性传递函数预测故障类型。最后,以某地区一年的二次设备运行数据作为算例进行分析。结果表明,所提方法能够去除冗余信息干扰,准确定位故障元件和诊断故障类型,为智能运维提供支持。

雪崩晶体管电压斜坡触发模式下终端失效机理研究

随着超宽带脉冲信号系统在新能源汽车智能化感知技术等许多重要领域的应用,高幅值、快前沿脉冲源的研发得到了广泛研究。针对纳秒级前沿脉冲对超快功率半导体开关的需求,进行了雪崩晶体管在电压斜坡触发模式下终端失效机理的研究。利用仿真模型的静态特性与器件样品进行对比分析,测试了器件样品的动态开通特性。在成功得到纳秒级开通速度器件的基础上,对器件在电压斜坡触发模式下出现的失效现象进行了分析。

智能变电站二次装置一键式隔离系统研究

由于通信机制虚拟化及网络化,智能变电站二次回路检修时难以对二次回路进行经济有效隔离。文中建立了智能变电站二次装置一键式隔离系统,并给出系统需要的软件和硬件配置方案。首先介绍了研究理论方法,利用无提取的可扩展标记语言解析方法对智能变电站IEC 61850 SCD配置文件进行快速解耦和分析计算,并把站内检修与改扩建过程中的隔离范围问题转化为图信号处理方法中的事件扩散问题,并通过图信号处理技术实现复杂数据处理算法可视化展示。然后给出了SV链路、GOOSE输出链路、GOOSE接收链路和软压板之间的对应规则,明确检修时隔离的范围。最后,对装置隔离的安全措施序列可视化生成,能够直观地显示二次回路的隔离情况,协助现场人员进行检修工作。

高频隔离型两相-单相贯通牵引供电装置及其控制策略

基于电力电子技术的贯通牵引供电系统为同时解决负序电能质量与电分相问题提供了契机,然而,现行贯通改造方案依然存在功率密度低、改造成本高等问题。为此,文中提出一种高频隔离型两相-单相贯通牵引供电装置及其控制策略,所提装置在充分利用既有两相牵引变压器的基础上,采用三端口高频隔离型直流变换器连接输入输出侧,减小装置体积的同时提升系统功率密度,有效降低贯通系统改造成本。此外,针对贯通牵引供电装置内存在的电能质量问题,提出一种二次纹波消除与功率均分控制策略,在有效抑制直流侧二次纹波与负序电能质量问题的同时,进一步减小了装置直流侧电容容值的选型,最高可达94.95%。最后,通过仿真与实验验证所提装置及其控制策略的可行性与可靠性。

船用蒸汽排放系统动态特性分析及控制研究

蒸汽排放系统是船舶核动力二回路系统的重要组成部分,在保证核动力系统安全性和机动性方面发挥着重要作用。传统的船舶蒸汽排放系统针对不同的排放工况设置了多种控制逻辑,且采用简单开环顺序控制,存在控制精度低、超调量大、稳定时间长、逻辑切换频繁等问题,难以适应新型全电推进船舶对系统稳定性和安全性的更高要求。鉴于此,以船舶核动力二回路蒸汽排放系统为研究对象,采用时域法、频域法、根轨迹法等,对不同功率水平下的蒸汽排放系统动态特性进行了详细分析,根据系统动态特性研究确定了PI控制参数,设计了新的蒸汽排放控制器,通过与传统控制策略进行对比分析,新设计的控制器不仅简化了控制逻辑,且取得了更加优越的控制性能,为新型船舶的蒸汽排放系统研制提供了有益参考。

变电站二次防误技术研究

针对二次设备状态转换过程中易发生误操作的问题,设计了一种智能变电站二次防误系统。采用直流系统、站用电低压系统、监控系统、二次控制回路、微机保护装置、测控装置和计量装置等构建防误系统;基于SVM和PCA算法的融合模型实现对变电站的一二次设备状态参数的实时监测;对变电站二次设备参数分析。试验结果表明,通过系统二次防误的精准度高达九成以上,为下一步研究奠定基础。

带光源医用吸引器+扩张套管在高血压脑出血患者中的应用

目的探讨带光源医用吸引器+扩张套管在脑出血患者术中应用,对其脑脊液中细胞因子的影响。方法选择陕西省核工业二一五医院神经外科,于2019年1月至2024年1月收治有手术指征的基底节区高血压脑出血患者107例,随机分为治疗组与对照组,两组均进行常规去骨瓣减压血肿清除手术,治疗组:使用带光源医用吸引器+专用扩张套管,在管腔内操作清除血肿。对照组:采用脑压板牵开脑组织,无影灯照明下清除血肿,观察对比两组的血肿清除率、手术时间、住院时间、GOS评分、脑脊液IL-1β、TNF-α水平及患者日常生活活动能力评分(ADL)。结果治疗组与对照组,血肿清除率基本相同,前者比后者手术时间缩短43.88 min,住院时间缩短13.26 d,前者脑脊液中IL-1β、TNF-α含量明显低于后者,患者日常生活活动能力评分(ADL)高于后者,差异均有统计学意义(P<0.05)。结论带光源医用吸引器+扩张套管,可以在良好的照明下清除血肿,减少脑组织牵拉,防止医源性损伤发生,减少患者脑脊液中IL-1β、TNF-α因子含量,减少术中及术后继发性神经损害的发生,改善患者预后。

复用医疗器械清洗消毒后不同保存方法与二次污染的研究

目的探讨复用医疗器械清洗消毒后不同保存方法对二次污染的影响。方法选取2022年3月至2023年3月乌鲁木齐市妇幼保健院消毒供应中心300件全新复用医疗器械,按照随机数字表法分为三组,每组100件。三组器械于血液中放置5 min后进行清洗消毒,A组保存于普通环境中,B组保存于无纺布中,C组保存于清洁容器中,于清洗消毒后0、6、24、48 h后采用目测法、光源放大镜法和ATP生物荧光检测法进行检测,比较三组的二次污染情况。结果清洗消毒后0、6、24、48 h,三组目测法及光源放大镜法的检测合格率为100%,差异无统计学意义(P>0.05);清洗消毒后0、6 h,三组ATP生物荧光检测法检测合格率比较,差异无统计学意义(P>0.05);清洗消毒后24、48 h,B、C组ATP生物荧光检测法检测合格率高于A组,差异有统计学意义(P<0.05)。结论复用医疗器械清洗消毒后放置于清洁容器或无纺布中能够有效保持器械的清洗消毒质量,避免二次污染。

一种VOCs处理装置应用问题和优化改造

挥发性有机物(VOCs)作为有毒有害物质,对空气质量造成了严重影响。其中活性炭吸附脱附及催化燃烧装置被广泛用于VOCs的控制排放,VOCs浓度较高时,存在无法稳定达标排放问题。通过对活性炭吸附脱附与催化燃烧原理及装置实际工况分析,对其进行了针对性的优化改造。改造后,非甲烷总烃平均排放浓度、平均排放速度分别达到7.61 mg/m^(3)和289.94 g/h,分别降低了76.70%和78.24%,完全满足VOCs排放标准。结果表明:通过优化改造,不仅提高了该装置对VOCs的处理效果,而且实现了VOCs稳定达标排放,达到了该区域空气质量控制的目的。

电力系统二次网络安全隔离装置设计要点探究

随着信息技术在电力系统中的应用越来越广泛,电力系统的运行管理也越来越依赖于信息技术,从而提高了电力系统的运行效率。目前,相关部门已对电网安全作出了相应的规定,但在实际的操作过程中,由于设备管理人员缺乏必要的安全意识、安全措施不到位等原因,导致电力系统运行过程中存在严重的信息泄漏、病毒入侵等现象。因此,为保证电力系统的正常运行,需要做好网络隔离装置设计工作。文章对隔离装置进行了介绍,并分析了其设计要点,以期为相关人员提供参考。

聚乙烯/聚氯乙烯绝缘电缆的特性及二次敷设技术优化

为了保证电力系统二次电缆的敷设效率与敷设质量,研究二次电缆敷设方法,改善电缆敷设施工周期长且容易出现质量问题的缺陷。采用穿管敷设方法,选取电缆盘驱动装置、电缆敷设滑轨装置、新型电缆固定抱箍装置作为电缆敷设装置,满足敷设路径最短及允许弯曲半径要求,依据从高至低的电压等级,从强电至弱电的敷设顺序,完成二次电缆的敷设工作。以某110 kV变电站作为二次电缆敷设的应用工程,选取40%含量的纳米填料制备的聚氯乙烯复合材料,作为二次电缆绝缘层材料。结果表明,电缆走向清晰,可追溯性强,电缆重叠次序良好,提高了二次电缆敷设质量。

二次电缆拉直实训辅助教具的设计与应用

变电站二次接线的安装质量与工艺水平直接影响电网的安全运行。为提高二次接线的施工工艺水平,文章针对技能实训过程中二次回路接线存在的问题,研制了一种二次电缆拉直实训辅助教具。该教具可对二次电缆进行高效准确地拉直。通过施工过程的拉力监测,直观地展示电缆拉直过程中受力的变化曲线,帮助学员快速地建立训练手感,提升培训效率和效果。