Design of a Control Device for Synthetic Making Test Based on Pre-Arcing Current Detection and Phase Control

The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated voltage. According to the realistic conditions of test stations in China, a control device based on pre-arcing current detection and phase control is proposed in this paper. A sample of the control device made up of DSP TMS320LF2407A is fabricated, in which the CPLD MAX7064 is used to transmit signals for EMC design. It can be applied in full voltage synthetic making test at a level of 126kV/63kA. The test results show that, it is accurate to control the making phase of the applied voltage, whether the closing is demanded at voltage peak or zero.

Investigation into Equivalency of Synthetic Test Circuit Used for Operational Tests of Thyristor Valves for UHVDC

With the growth of capacity of high voltage direct current(HVDC) transmission lines,the ratings of thyristor valves,which are one of the most critical equipments,are getting higher and higher.Verification of performance of thyristor valves particularly designed for HVDC project plays an important role in the handover of products between the manufacturer and the client.Conventional test facilities based on philosophy of direct test cannot meet the requirements for modern thyristor valves.New test facilities with high ratings are necessarily built based on philosophy of synthetic test.Over the conventional direct test circuit,the later is an economical and feasible solution with less financial investment and higher test capability.However,the equivalency between the synthetic test and the direct test should be analyzed technically in order to make sure that the condition of verification test in a synthetic test circuit should satisfy the actual operation condition of thyristor valves existing in a real HVDC project,just as in a direct test circuit.Equivalency analysis is focused in this paper,covering the scope of thyristor valves' steady state,and transient state.On the basis of the results achieved,a synthetic test circuit of 6 500 A/50 kV for operational tests of thyristor valves used for up to UHVDC project has newly been set up and already put into service in Xi'an High Voltage Apparatus Research Institute Co.,Ltd.(XIHARI),China.Some of the results have been adopted also by a new national standard of China.

SYNTHETIC STRESSLIFE TESTING OF MECHATRONIC PRODUCTS UNDER VARIABLE STRESS SPECTRUM

Mechatronic products usually endure the variable stress spectrum when they operate in certain operational condition and environmental condition, which obey the Weibull distribution. In accordance with the features of mechatronic product, this paper analyzes the failure mode, its corresponding sensitive stress and the design principles of life testing profiles. Based on the above analyses, this paper presents a synthetic stress life testing method based on the hybrid Weibull distribution and its statistical method under variable stress spectrum to evaluate the reliability and life indices of mechatronic products. Because the mechatronic products have many characteristics such as high price, long life and small testing samples, the synthetic stress life testing method under variable load spectrum can simulate the real various spectra, decrease the life testing time and reduce the testing samples. So it is effective to carry out the life testing to mechatronic products. The application results of hydraulic pumps indicate that this method can easily handle the experimental data under variable amplitude spectrum, obtain the high precision parameters point estimation and confidence interval estimation and reduce the testing cost greatly.

Dimensional analysis of the impact toughness test for synthetic diamond grits

The method,in which a few carats of diamond grits are placed inside a capsule together with a steel ball,shaken for a number of times,and the unbroken ratio of the grits is then used to evaluate the quality of the diamond,has been well established for many years.However,the unbroken percentage,in an equivalent view,represents the impact toughness of the grits and cannot reflect the value of the crushing energy.Most of the previous empirical formulas obtained from experiments by scholars cannot be applied to practical tests.In this paper,a dimensional analysis was applied to investigate the impact toughness experiment,and the dimensionless relationship has been built among those variables such as the toughness index,the impact time,the impact frequency and the crushing energy per unit area.According to the results of a large number of experiments with synthetic diamond grits of mesh size 45/50,the percentage of the broken grits H is proportional to the impact time T^（1.14） when the impact frequency is 2400 r/min,and the impact frequency f^（2.576） when the number of impacts is 2000.

Synthetical Efficiency-based Optimization for the Power Distribution of Power-split Hybrid Electric Vehicles

Now the optimization strategies for power distribution are researched widely, and most of them are aiming to the optimal fuel economy and the driving cycle must be preknown. Thus if the actual driving condition deviates from the scheduled driving cycle, the effect of optimal results will be declined greatly. Therefore, the instantaneous optimization strategy carried out on-line is studied in this paper. The power split path and the transmission efficiency are analyzed based on a special power-split scheme and the efficiency models of the power transmitting components are established. The synthetical efficiency optimization model is established for enhancing the transmission efficiency and the fuel economy. The identification of the synthetical efficiency as the optimization objective and the constrain group are discussed emphatically. The optimization is calculated by the adaptive simulated annealing （ASA） algorithm and realized on-line by the radial basis function （RBF）-based similar models. The optimization for power distribution of the hybrid vehicle in an actual driving condition is carried out and the road test results are presented. The test results indicate that the synthetical efficiency optimization method can enhance the transmission efficiency and the fuel economy of the power-split hybrid electric vehicle （HEV） observably. Compared to the rules-based strategy the optimization strategy is optimal and achieves the approximate global optimization solution for the power distribution. The synthetical efficiency optimization solved by ASA algorithm can give attentions to both optimization quality and calculation efficiency, thus it has good application foreground for the power distribution of power-split HEV.

RELIABILITY-BASED DESIGN AND ANALYSIS ON HYDRAULIC SYSTEM FOR SYNTHETIC RUBBER PRESS

To overcome the design limitations of traditional hydraulic control systemfor synthetic rubber press and such faults as high fault rate, low reliability, highenergy-consuming and which always led to shutting down of post-treatment product line for syntheticrubber, brand-new hydraulic system combining with PC control and two-way cartridge valves for thepress is developed, whose reliability is analyzed, reliability model of the hydraulic system for thepress is established by analyzing processing steps, and reliability simulation of each step and thewhole system is carried out by software MATLAB, which is verified through reliability test. Thefixed time test has proved not that theory analysis is sound, but the system has characteristics ofreasonable design and high reliability, and can lower the required power supply and operationalenergy cost.

A Fiber Pull-Out Based Model for Synthetic Fiber Reinforced Concrete Beams under a Flexural Load

This work is intended to be a simple contribution to building a model able to implement theoretical results related to the random oriented fiber reinforced concrete in a procedure that could be used in structures analysis and design involving fiber reinforced elements. Here follows a short outline: In the introduction chapter the problem is presented together the work done. Section 2 develops some ancillary concepts of this material and its mechanical properties, while in Section 3, following the path of other researchers, the assumptions made to solve the problem are presented, together with the most relevant results related to presence of 3D randomly oriented fiber. In the following section a review of the mechanical process of fiber pull-out is done, and the results, mostly due to Victor Li researches, of a 3D randomly oriented synthetic fiber stress vs crack opening in a pull-out process from a cement matrix. In Section 5 the author, after making some assumptions about the configuration of the strain and crack geometry in the cross section where failure is assume to occur under flexural bending moment, the resultant stress is integrated to find the resultant internal moment vs increasing strain and crack width. In this analysis, the crack bridging law for synthetic fiber in FRC presented in the previous section is taken into account. In Section 6, a procedure to find a cross section configuration in equilibrium under external bending moment has been built. Under the assumption of a perfectly plastic collapse mechanism a numerical simulation is conducted on a specimen that undergoes a four-point bending test. A comparison with the trend of a similar test on a synthetic FRC sample has been done. The work is completed by the conclusions that could be inferred from this work.

Forecasting the Quasi-stationary Front Rainstorm in Southeast China Using the Synthetically Multilevel Analog Forecast Technology

The authors use numerical model integral products in a third level forecast of synthetically multi-level analog forecast technology.This is one of the strongest points of this study,which also includes the re-ducing mean vacant-forecast rate method,which pos-sesses many advantages with regard to filtering the analog term.Moreover,the similitude degree between samples is assessed using a combination of meteorological elements,which works better than that described using a single element in earlier analog forecast studies.Based on these techniques,the authors apply the model output,air sounding,surface observation and weather map data from 1990 to 2002 to perform an analog experiment of the quasi-stationary front rainstorm.The most important re-sults are as follows:(1) The forecast successful index is 0.36,and was improved after the forecast model was re-vised.(2) The forecast precise rate (0.59) and the lost-forecast rate (0.33) are also better than those of other methods.(3) Based on the model output data,the syn-thetically multilevel analog forecast technology can pro-duce more accurate forecasts of a quasi-stationary front rainstorm.(4) Optimal analog elements reveal that trig-gering mechanisms are located in the lower troposphere while upper level systems are more important in main-taining the phase of the rainstorm.These variables should be first taken into account in operational forecasts of the quasi-stationary front rainstorm.(5) In addition,experi-ments reveal that the position of the key zone is mainly decided by the position of the system causing the heavy rainfall.

可控换相换流阀可控关断试验研究及工程应用

高压直流可控换相换流(controllable line commutated converter,CLCC)阀采用晶闸管与绝缘栅双极晶体管(insulated gate bipolar transistor,IGBT)器件混联的方式,形成主、辅两条支路并联结构,主支路起正常通流作用,发生交流故障时由辅助支路承接主支路电流,待主支路恢复阻断后主动关断实现强迫换相,从根本上解决直流系统换相失败的难题,适用于我国多馈入直流受端电网。为等效复现可控换相换流阀稳态运行下电热应力以及交流故障期间连续强迫换相过程产生的瞬变高电压、大电流及脉冲能量,需开展阀组件可控关断试验方法研究,验证CLCC换流阀抵御换相失败能力。依托葛南直流改造工程系统仿真结果,分析了逆变侧单相接地故障下各子阀瞬变高压、大电流应力水平,提取实际工况下各子阀关键应力指标;其次,提出了多频谐振电流源、稳态高压源周期性复合试验方法,完成故障电流连续分断试验装置参数设计,实现无外部负向电压施加时桥臂可控阻断恢复能力的模拟。通过试验和仿真对比分析,验证了该试验方法的可行性及等效性,为后续不同电流等级可控换相换流阀可控关断试验提供理论和技术指导。

General Consideration of Measuring System for Operational Test of Thyristor Valves of Ultra High Voltage DC Power Transmission

Thyristor valve is one of the key equipments for ultra high voltage direct current(UHVDC) power transmission projects.Before being installed on site,they need to be tested in a laboratory in order to verify their operational performance to satisfy the technical specification of project related.Test facilities for operational tests of thyristor valves are supposed to enable to undertake more severe electrical stresses than those being applied in the thyristor valves under test(test objects).On the other hand,the stresses applied into the test objects are neither higher nor lower than specified by the specification,because inappropriate stresses applied would result in incorrect evaluation of performance on the test objects,more seriously,would cuase the damage of test objects with expensive cost losing.Generally,the process of operational tests is complicated and performed in a complex synthetic test circuit(hereafter as STC),where there are a lot of sensors used for measuring,monitoring and protection on line to ensure that the test circuit functions in good condition.Therefore,the measuring systems embedded play a core role in STC,acting like "eyes".Based on the first project of building up a STC in China,experience of planning measuring systems is summarized so as to be referenced by related engineers.

基于极化SAR梯度和复Wishart分类器的舰船检测

舰船检测是极化SAR系统的重要应用之一。现有的舰船检测方法容易受到旁瓣泄露的干扰,使得舰船目标的形态难以提取,导致检测结果不符合真实情况。此外,在舰船过于密集、尺度不一致的情况下,相邻舰船由于旁瓣的影响有时会被认为是单个目标,从而造成漏检。针对这些问题,该文提出一种基于极化SAR梯度和复Wishart分类器的舰船检测方法。首先,将似然比检验(LRT)梯度引入对数比值梯度框架,使其适用于极化SAR数据;基于LRT梯度图进行恒虚警(CFAR)检测,提取舰船的边缘信息,消除伪影的同时抑制强旁瓣对舰船精细轮廓提取的影响。其次,利用复Wishart迭代分类器对舰船强散射部分进行检测,可排除大部分的杂波干扰且保持舰船形态细节。最后,将二者信息融合,从而可以保持舰船形态细节的同时克服旁瓣和伪信号的虚警。该文在3幅来自ALOS-2卫星的极化SAR图像上进行了对比实验,实验表明与其他方法相比,该文所提算法具有更少的虚警和漏检,且能够有效克服旁瓣泄露,保持舰船形态细节。

直流断路器全工况串联型合成等效试验方法

混合式高压直流断路器作为直流电网的关键设备之一,完备的型式试验是保证其挂网运行时快速、可靠清除故障电流和故障恢复的重要手段。为了更好地等效混合式直流断路器分断及故障恢复过程中的高电压与大电流工况,研究了混合式直流断路器开断大电流和故障清除失败情况下的重合闸全过程等效性评价指标,提出了一种新型串联式的全压全流合成等效试验方法,通过适当的控制方式,方案可以在不过多增加控制复杂度,实现试验全工况等效,并通过对电容器组的高效复用,降低了试验的成本。在该方案中,试验回路由大电流回路和高电压回路串联,通过大电流回路单独提供开断电流,在断路器开断结束后投入高压试验回路,两个回路共同作用提供开断后稳态电压和重合闸的二次电流。通过对4 kV/8 kA断路器进行开断及重合闸实验,验证了该试验回路的可行性,并针对500 kV/25 kA工况下的断路器对比了该试验回路与现有并联合成试验回路,结果表明串联式的全压全流合成试验方法在等效性、二次控制简易性和经济性方面存在优势,为直流断路器全工况等效试验提供另一种可选择方案。

模拟生活干垃圾循环流化床气化试验

为给工业化循环流化床垃圾气化技术研发提供基础数据,在中试规模循环流化床气化试验台,研究过量空气系数和系统富氧体积分数对模拟生活干垃圾(简称“干垃圾”)气化特性影响。试验用干垃圾为单组分垃圾料配置而成的压块料,组成包括纸张、织物、木屑、灰渣和水,分别按质量分数60%、10%、10%、10%及10%配比,并通过用干垃圾压块料和工业锅炉底渣交错加料的方式解决了中试试验中压块料进料不畅的问题。通过试验发现干垃圾空气气化条件,过量空气系数由0.31提至0.50,气化温度会由850℃提至950℃,生成的煤气热值3976~2590 kJ/m^(3),煤气中CO产率增加,H_(2)产率先增加后减少,CH_(4)产率减少,煤气产气率2.28~3.08 m^(3)/kg,冷煤气效率42.97%~51.01%,碳转化率83.11%~92.45%;在900℃条件系统富氧体积分数由30%升高至50%时,水煤气反应得到强化,煤气有效组分(CO+H_(2)+CH_(4))产率和煤气热值均得到提高,煤气热值5274~7294 kJ/m^(3),煤气产气率1.37~1.93 m^(3)/kg,碳转化率83.32%~81.11%,冷煤气效率55.39%~53.77%;模拟生活干垃圾在中试规模循环流化床气化炉内实现稳定空气气化和富氧-水蒸汽气化运行,炉膛底部温度低,炉膛底部至顶部高度范围内温度分布较为均匀,装置稳定连续运行108 h,温差在19.7℃以内,中试规模循环流化床内部物料循环稳定。

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。

基于混凝土缺陷超声检测的合成孔径聚焦成像

由于混凝土的随机性,超声波在混凝土中传播伴随着强烈的衰减、反射以及散射作用,回波信号信噪比低,带有损伤信息的有效反射信号同背景噪声混叠畸变。传统超声信号处理难以识别缺陷的具体信息,本文引入了频域合成孔径聚焦算法对超声回波数据进行成像处理,并开展了对混凝土空洞缺陷的数值模拟和试验研究,采用道内平衡处理方法,对混凝土深部信号进行了增强处理,提高了缺陷回波的质量,对多次自发自收数据进行了频域合成孔径成像处理,空洞缺陷的绕射波被收敛,提高了100 kHz超声波的检测成像效果;同时预制了双空洞混凝土试件,使用宽频带窄脉冲探头进行现场混凝土空洞缺陷超声波检测试验,结果与数值模拟结果基本吻合,证明了合成孔径聚焦技术能够使混凝土缺陷的绕射波得到了很好的收敛,有效提高了小孔径超声波探头的分辨率。

新型IGCT直流输电换流阀运行试验研究及其等效性评估

换相失败问题(commutation failure,CF)是电网换相换流高压直流输电技术(line commutated converter high voltage directcurrent,LCC-HVDC)面临的固有难题。为了解决该问题,已有文献主要从拓扑结构、控制策略等方面着手,鲜见抵御换相失败的新型换流阀研制及试验研究。该文开展基于大功率逆阻型集成门极换流晶闸管(reverse blocking integrated gate commutated thyristor,RB-IGCT)的新型换流阀试验研究及试验等效性分析。首先,阐释新型换流阀抵御换相失败的原理,并针对新型换流阀不同的工作模式,提出对新型电力电子器件的需求。然后,利用现有的型式试验合成回路平台开展适用于传统晶闸管换流阀的运行试验,并分析试验结果,得出大部分试验项目等效性较好而小熄弧角试验和关断试验等效性较差的结论。最后,针对这两项特殊试验提出新的试验方法和试验电路,可为新型换流阀的研发和应用提供一定的技术基础。

绕月SAR天线热控设计

合成孔径雷达(SAR)天线是遥感卫星的重要载荷之一,面对月球轨道舱外天线复杂的外热流环境,结合轨道特点,对天线开展了详细的外热流分析,解析了月球环境的热设计难点,进行了针对性的热控设计,解决了极地轨道下天线在一个很大的外热流和极小的外热流间不断循环的问题。采用TMG软件对天线进行了热仿真分析,并利用热模拟件进行了热平衡试验。分析和试验结果表明,天线各单机温度满足指标要求。本文适用于平板SAR天线,对有源SAR天线的热控设计具有一定的借鉴意义。

基于两电平电压源合成试验方法的混合式直流断路器开断过程仿真研究

直流断路器在研究过程中需要试验测试为设计提供参考,在其制造完成后则需要进行型式试验验证其可靠性。文中以15 kV电压等级的负压耦合型混合式直流断路器为例,对其短路电流开断过程进行仿真并提取了关键点电应力;阐述了两电平电压源合成试验方法,设计了适用于负压耦合型混合式直流断路器的两电平电压源合成试验回路,并优化了参数选取;将两电平回路下开断过程的仿真结果与开断过程所需的电应力进行对比,证明了两电平电压源合成试验方法可以提供开断过程所需的电压与电流应力,验证了两电平合成试验方法的等效性与可行性。文中研究结果可为高压直流断路器的研究、设计及试验提供参考。

基于红外光谱法和气相色谱-质谱法的两种烷基甲酰吲唑类合成大麻素的结构区分

采用红外光谱法和气相色谱-质谱法对两种烷基甲酰吲唑类合成大麻素ADB-4enPINACA和MDMB-4en-PINACA标准品结构进行区分,并对实际烟丝检材中的这两种化合物进行鉴定。结果显示:ADB-4en-PINACA的特征峰位于3354.1,3208.7,682.3 cm^(-1)处,保留时间19.098 min,母离子m/z 342.2,主要子离子m/z 213.1,241.2;MDMB-4en-PINACA的特征峰位于3411.8,1725.4 cm^(-1)处,保留时间13.238 min,母离子m/z 357.2,主要子离子m/z 213.1,270.1。两种化合物产生差异的原因在于ADB-4en-PINACA末端基团为酰胺基,而MDMB-4en-PINACA末端基团为酯基。采用气相色谱-质谱法对疑似含有ADB-4en-PINACA和MDMB-4en-PINACA的样品进行分析,所得质谱特征峰和标准品的基本一致。

Novel roll effector based on zero-mass-flux dual synthetic jets and its flight test

The autonomous and controllable Dual Synthetic Jet Actuator(DSJA)is firstly integrated into the Unmanned Aerial Vehicle(UAV),and flight tests without the deflection of rudders are carried out to verify the viability of DSJA to control the attitudes of UAV during cruising.DSJA is improved into an actuator with two diaphragms and three cavities,which has higher energy levels.Actuators,differentially distributed on both sides of the wings,are installed on the trailing edge close to the wing tips.Flight tests,containing Differential Circulation Control(DCC)using double-side actuators,Positive Circulation Control(PCC)using left-side actuators and Negative Circulation Control(NCC)using right-side actuators,are implemented at cruising speed of 25 m/s.Results show that roll attitude control without rudders could be realized by DSJAs.DCC and NCC can generate the rightward roll and yaw angular velocity,prompting UAV to turn right.The stronger controlling ability can be achieved by DCC,with the maximum roll angular velocity of 15.62(°)/s.PCC can generate a rightward roll moment,but a leftward yaw moment will be produced at the same time.Leftward yaw induces the leftward rolling moment,which weakens the roll control effect,making UAV keep to yaw to the left with a small slope.