考虑异步通信的配电-气网分布式有功-无功协同优化

配电-气网(EGDN)中新能源大量并网和燃气运输过程中管网压力变化均可能导致配电网的电压波动增大。文中提出一种考虑异步通信的EGDN有功-无功协同优化方法。首先,研究EGDN中各元件的有功-无功特性;其次,根据EGDN能量运输过程中无功需求特性,建立EGDN无功供需模型;然后,考虑EGDN无功平衡和网络运行约束,以最小化电网电压波动、网损和EGDN购电/气成本为目标,建立EGDN无功电压优化控制模型;最后,为保障EGDN中各能源主体信息的安全性与私密性,考虑配电网与配气网信息采集传输情况存在差异,可能存在通信延迟和信息丢包情况,采用异步交替方向乘子法对模型进行求解。通过对改进的IEEE 33节点系统和7节点配气网构成的EGDN系统进行仿真,结果表明,所提方法可有效缓解EGDN电压波动问题,减小网损并降低系统总运行成本。

基于混合整数二阶锥的配电-气网联合规划

提出了一种考虑配电网重构及小时级潮流变化的配电-气网(EGDN)联合规划模型。一方面,融入配电网重构来优化系统的运行状态,两网协同规划能发挥不同能源间的互补共济作用,提升系统的可靠性和运行效率;另一方面,所提模型考虑小时级配电网和配气网的潮流方程,以精细化描述系统的运行状态。为了求解该非线性非凸模型,适当松弛原问题,将其转换为可直接求解的混合整数二阶锥规划(MISOCP)问题。仿真结果表明所提规划模型显著提升了系统的可靠性,降低了相关设备的配置容量,减少了能量传输损耗,降低了总体规划与运行费用,证明了MISOCP模型与简单的混合整数线性规划模型相比,更能获得满足实际工程需求的规划方案。

浅谈建筑电气供配电线路设计

伴随着我国经济建设发展的步伐逐渐加快,人口政策调整,基础设施建设加大投入,对于城市化建设的投资也越来越多,电力资源的消耗亦逐渐增大.为了促进城市经济发展中节能、环保问题的同步发展,对于建筑工程中的电气供配电线路设计的研究就变得很有必要.

配电所开关跳闸原因浅析

对铁路 10kV配电所开关跳闸进行分类分析 ,找出引起配电开关跳闸原因的规律 ,并提出针对性的措施 。

配网施工现场的安全管理分析

目的:为了保证电力工程的正常运行,本文主要讨论了配气施工现场的安全管理的方法。方法:配气工程现场安全管理是一项复杂的系统管理,“人、机、物、法、环”五要素环环相扣,供电公司基于安全管理要素,提出提升人员素质、严审机械资质、保障物资品质、探寻方法本质、挖掘环境潜质的“五质融合”模式,筑牢配气工程施工现场安全气。结论:通过对施工安全管理问题的分析,制定有效安全管理方案,保证电力施工管控工作正常进行。

民营企业追求卓越质量管理之路

德力西创立于1984年7月,是一家以生产高低压电器、输配电气和工业自动化控制电气为主的大型民营企业,现有下属公司70多家,协作企业700多家,总资产达40多亿元,品牌的无形资产为28.28亿元.德力西商标被认定为"中国驰名商标",三类产品被评为"中国名牌产品",电能表获得了"国家免检产品"称号.2003年金秋,德力西电气进入高科技航天领域,力助"神舟五号"载人航天飞行取得圆满成功,标志着公司产品在可靠性、安全性方面已经达到国内外一流水平.

Flow Past an Accumulator Unit of an Underwater Energy Storage System： Three Touching Balloons in a Floral Configuration

An LES simulation of flow over an accumulator unit of an underwater compressed air energy storage facility was conducted. The accumulator unit consists of three touching underwater balloons arranged in a floral configuration. The structure of the flow was examined via three dimensional iso surfaces of the Q criterion. Vortical cores were observed on the leeward surface of the balloons. The swirling tube flows generated by these vortical cores were depicted through three dimensional path lines. The flow dynamics were visualized via time series snapshots of two dimensional vorticity contours perpendicular to the flow direction; revealing the turbulent swinging motions of the aforementioned shedding-swirling tube flows. The time history of the hydrodynamic loading was presented in terms of lift and drag coefficients. Drag coefficient of each individual balloon in the floral configuration was smaller than that of a single balloon. It was found that the total drag coefficient of the floral unit of three touching balloons, i.e. summation of the drag coefficients of the balloons, is not too much larger than that of a single balloon whereas it provides three times the storage capacity. In addition to its practical significance in designing appropriate foundation and supports, the instantaneous hydrodynamic loading was used to determine the frequency of the turbulent swirling-swinging motions of the shedding vortex tubes; the Strouhal number was found to be larger than that of a single sphere at the same Reynolds number.

A novel current-sharing scheme based on magamp

The magamp (magnetic amplifier) is widely used in power supplies due to its low cost, simplicity and other advan-tages. This paper discusses a novel application of the magamp in switching power supplies, where the magamp is used to regulate pulse width modulation (PWM) instead of power signal in the main circuit. This method extends the application of the magamp in power supplies, and makes it possible to further regulate control signal when PWMs have been generated. Based on this applica-tion, a new current-sharing (CS) scheme using the magamp is proposed, which uses a modified inner loop CS structure. In this scheme PWMs are generated by one main controller, and CS is achieved by regulating PWMs using a magamp in each module. Compared with traditional application of the magamp, the new CS scheme can be used in most topologies and only requires magamps of low power capacity. Then a test circuit of parallel power supply is developed, in which CS is achieved by a PWM regulator with the magamp. The proposed scheme is also used to upgrade an electroplate power to make it capable of paralleling supplies. Experimental results show that the proposed scheme has good CS performance.

Analysis on the Application of Reactive Power Compensation Technology in Electrical Automation

This paper introduces in detail the reactive power compensation technology and its characteristics, to reduce the loss of reactive power compensation technology 1N power distribution system and the electrical automation, improve the utilization rate, and realize the control of the voltage amplitude in the system network, voltage stability of power distribution system, has carried on the system analysis to reduce failure of the harmonic current to the power supply system and other functions. And the paper in-depth study on the application of reactive power compensation technology in electrical automation from the reactive compensation technology, substation and distribution line reactive power compensation, power users of reactive power compensation and other aspects.

Powermitter:Data Exfiltration from Air-Gapped Computer through Switching Power Supply

Air-gapped computers are isolated both logically and physically from all kinds of existing common communication channel, such as USB ports, wireless and wired net- works. Although the feasibility of infiltrating an air-gapped computer has been proved in recent years, data exfiltration from such sys- tems is still considered to be a challenging task. In this paper we present Powermittcr, a novel approach that can exfiltrate data through an air-gapped computer via its power adapter. Our method utilizes the switched-mode pow- er supply, which exists in all of the laptops, desktop computers and servers nowadays. We demonstrate that a malware can indirectly con- trol the electromagnetic emission frequency of the power supply by leveraging the CPU utili- zation. Furthermore, we show that the emitted signals can be received and demodulated by a dedicated device. We present the proof of con- cept design of the power covert channel and implement a prototype of Powermitter consist- ing of a transmitter and a receiver. The trans- mitter leaks out data by using a variant binary frequency shift keying modulation, and the emitted signal can be captured and decoded by software based virtual oscilloscope through such covert channel. We tested Powermitter on three different computers. The experiment re-suits show the feasibility of this power covert channel. We show that our method can also be used to leak data from different types of embedded systems which use switching power supply.

Stiffness-damping matching method of an ECAS system based on LQG control

A novel method of matching stiffness and continuous variable damping of an ECAS(electronically controlled air suspension) based on LQG(linear quadratic Gaussian) control was proposed to simultaneously improve the road-friendliness and ride comfort of a two-axle school bus.Taking account of the suspension nonlinearities and target-height-dependent variation in suspension characteristics,a stiffness model of the ECAS mounted on the drive axle of the bus was developed based on thermodynamics and the key parameters were obtained through field tests.By determining the proper range of the target height for the ECAS of the fully-loaded bus based on the design requirements of vehicle body bounce frequency,the control algorithm of the target suspension height(i.e.,stiffness) was derived according to driving speed and road roughness.Taking account of the nonlinearities of a continuous variable semi-active damper,the damping force was obtained through the subtraction of the air spring force from the optimum integrated suspension force,which was calculated based on LQG control.Finally,a GA(genetic algorithm)-based matching method between stepped variable damping and stiffness was employed as a benchmark to evaluate the effectiveness of the LQG-based matching method.Simulation results indicate that compared with the GA-based matching method,both dynamic tire force and vehicle body vertical acceleration responses are markedly reduced around the vehicle body bounce frequency employing the LQG-based matching method,with peak values of the dynamic tire force PSD(power spectral density) decreased by 73.6%,60.8% and 71.9% in the three cases,and corresponding reduction are 71.3%,59.4% and 68.2% for the vehicle body vertical acceleration.A strong robustness to variation of driving speed and road roughness is also observed for the LQG-based matching method.

A hardware-based algorithm for virtual machine provisioning in a private cloud

Cloud computing is becoming a key factor in the market day by day. Therefore, many companies are investing or going to invest in this sector for development of large data centers. These data centers not only consume more energy but also produce greenhouse gases. Because of large amount of power consumption, data center providers go for different types of power generator to increase the profit margin which indirectly affects the environment. Several studies are carried out to reduce the power consumption of a data center. One of the techniques to reduce power consumption is virtualization. After several studies, it is stated that hardware plays a very important role. As the load increases, the power consumption of the CPU is also increased. Therefore, by extending the study of virtualization to reduce the power consumption, a hardware-based algorithm for virtual machine provisioning in a private cloud can significantly improve the performance by considering hardware as one of the important factors.

Radio-frequency spectroscopic measurement for pairing gap in an ultracold Fermi gas

The study of ultracold Fermi gases has exploded a variety of experimental and theoretical research since the achievement of degenerate quantum gases in the lab,which expands the research range over atomic physics,condensed matter physics,astrophysics and particle physics.Using the Feshbach resonance,one can tune the attractive two-body interaction from weak to strong and thereby make a smooth crossover from the BCS superfluid of cooper pairs to the Bose Einstein condensate of bound molecules.In this crossover regime,the pairing effect plays a significant role in interpreting the interaction mechanism.Whenever the localized or delocalized pairing occurs at sufficiently low temperature,the single-particle energy will shift with respect to free atoms,due to the two-body or many-body interaction.Measuring the pairing gap can improve the understanding of the thermodynamics and hydrodynamics of the phase transition from the pseudogap to the superfluid,which will make an analogue to the high-temperature superconductivity in condensed matter.In this work,we will give a brief introduction to a novel radio-frequency(RF) spectroscopic measurement for pairing gap in an ultracold Fermi gas,which is currently widely used on the ultracold atomic table in the lab.In different interaction regimes of the BEC-BCS crossover,ultracold atoms are excited with a RF pulse and the characteristic behavior can be extracted from the spectrum.