VSP5型配电网自动化系统

为适应国家电力公司提出配电网自动化设备真空ＳＦ６标准化、智能化、无人值班的需要,满足供电可靠率必需达到９９．９９％的要求,选用能自动检测、自动隔离故障段及自动恢复配电网络非故障段供电的柱上自动化设备实现配电网自动化就现得十分重要而迫切。ＶＳＰ５型配电...     

Optimal configuration analysis for a campus microgrid—a case study

The foremost issues of 21st century are challenging demand of electrical energy and to control the emission of Green House Gases (GHG) emissions. Renewable energy resources based sustainable microgrid emerges as one of the best feasible solution for future energy demand while considering zero carbon emission, fossil fuel independency, and enhanced reliability. In this paper, optimization and implementation of institutional based sustainable microgrid are discussed based on cost analysis, carbon emission, and availability of energy resources. Various microgrid topologies are considered for addressing the most ideal solution. The metrological data such as irradiance is acquired from solar satellite data of NASA (National Aero Space Agency) while the data for wind speed is taken from synergy enviro engineer’s site. HOMER® simulation tool is used for modelling and optimization purpose.     

Simulation of a current-mode controlled DC–DC boost converter in chaotic regime evaluating different simulation methods

The main objective of the paper is to evaluate and demonstrate different simulation tools for the simulation of switch-mode power supplies. Also the modelling process from the design engineers point of view is considered. A current-mode controlled DC–DC boost converter in chaotic regime is chosen as an application example because it offers an up-to-date and challenging simulation problem. Simulations carried out with the conventional Spice circuit simulator, switched state-space model implemented in the Matlab/Simulink simulation environment and Power System Blockset extension are compared with each other and also partly with analytical predictions and the results obtained with discrete-time two-dimensional mapping. Experiments are performed to conclude the validity of the simulation results.     

Optimal configuration analysis for a campus microgrid—a case study

The foremost issues of 21st century are challenging demand of electrical energy and to control the emission of Green House Gases (GHG) emissions. Renewable energy resources based sustainable microgrid emerges as one of the best feasible solution for future energy demand while considering zero carbon emission, fossil fuel independency, and enhanced reliability. In this paper, optimization and implementation of institutional based sustainable microgrid are discussed based on cost analysis, carbon emission, and availability of energy resources. Various microgrid topologies are considered for addressing the most ideal solution. The metrological data such as irradiance is acquired from solar satellite data of NASA (National Aero Space Agency) while the data for wind speed is taken from synergy enviro engineer’s site. HOMER® simulation tool is used for modelling and optimization purpose.     

Power system planning — a reliability perspective

One of the basic objectives of power system planners is to determine the necessary generating capacity to satisfy the system demand in the presence of scheduled and unscheduled outages and unforeseen variations in the system load. A second important objective is the development of a suitable transmission network to transport the generated electrical energy to the bulk load centers. This aspect is dealt with in conjunction with the available and planned generation facilities. Lastly, adequate distribution facilities must be constructed in order to deliver the available energy from the bulk load centers to the actual customer premises. The reliability at which these three subsystems (namely, generation, transmission, and distribution) will function is of utmost importance. The power system engineer, therefore, must consider the reliability aspect right from the beginning, i.e. from the planning stage. This paper presents the basic concepts of power system reliability assessment and reviews the relability indices and methodologies from a planning viewpoint and also from an economic cost-benefit perspective. Some realistic data which can be used as a guide in the absence of any collected system data are also presented.     

Multi-phase induction machine drive research—a survey

Due to the potential benefits resulting from the use of a phase order higher than three in transmission, some interest has also grown in the area of multi-phase machine. For machine drive applications, multi-phase system could potentially meet the demand for high power electric drive systems, which are both rugged and energy-efficient. High phase number drives possess several advantages over conventional three-phase drives such as: reducing the amplitude and increasing the frequency of torque pulsation, reducing the rotor harmonic currents, reducing the current per phase without increasing the voltage per phase, lowering the dc link current harmonics, higher reliability and increased power in the same frame. The high phase order drive is likely to remain limited to specialized applications where high reliability is demanded such as electric/hybrid vehicles, aerospace applications, ship propulsion, and high power application where a combination of several solid state devices form one leg of the drive. The research has been underway for the last two decades to investigate the various issues related to the use of multi-phase machine as a potential alternative to the conventional three-phase machine. This paper, therefore, reviews the progress made in multi-phase induction machine drive research and development since its inception. Attempts are made to highlight the current and future issues involved for the development of multi-phase induction machine drive technology for future application.     

Dynamic simulation test to verify UHV protective relays

In order to support the development and type selection of relay protection devices for the demonstrative 1000-kV UHVAC transmission project, the China Electric Power Research Institute （CEPRI）, entrusted by the State Grid Corporation, carried out dynamic simulation tests on all relevant protective relays produced by main domestic manufacturers.     

RSVIES—a relay setting value identification expert system

This paper presents an expert system for relay setting value checking during the change of power system topology due to normal switching operations. With the help of this system, relay engineers can easily find incorrect relay setting values so that the proper coordination can be made. This expert system consists of a network parameter correction module, a fault calculation module, a graphic module, and a checking module. The main body of this expert system was coded with Prolog and the fault calculation module in Fortran so that a hybrid system was achieved. According to the tests on a 110 kV power system, this prototype can correctly check the relay setting values for the given power system so that it can be used as an efficient aid for relay engineers in power system dispatch centers.     

怎样维修“HFC—134a”制冷剂冰箱

美国杜邦(DuPont)公司推出了HFC—134a,即四氯乙烷,它仍属于卤代烃类,但不含氟和溴,所以ODP(Ozone Deplete Potentia即臭氧消耗潜值)为零。家用电冰箱发展到现在,主要采用的制冷剂有:R12(CFC—12)、R134a(HFC—134a)、HC—600a等。用HFC—134a制冷剂替代R12(CFC—12)的应用技术日趋成熟。这类电冰箱从箱体结构,主要组成部件、制冷系统、电气系统与HFC—134a电冰箱基本相同,因而常见故障表现特征与维修技术方面具有很多的相同或相似之处,但是也存在一些差异,主要是制冷剂特性所引起的有关材料及维修工艺不同。下面介绍如何提高这类冰箱的检修质量及正确维修应注意的一些问题。     

A simulation study of short channel effects with a QET model based on Fermi–Dirac statistics and nonparabolicity for high-mobility MOSFETs

In this paper, the quantum confinement and short channel effects of Si, Ge, and \(\hbox {In}_{0.53}\hbox {Ga}_{0.47}\)As n-MOSFETs are evaluated. Both bulk and double-gate structures are simulated using a quantum energy transport model based on Fermi–Dirac statistics. Nonparabolic band effects are further considered. The QET model allows us to simulate carrier transport including quantum confinement and hot carrier effects. The charge control by the gate is reduced in the Ge and \(\hbox {In}_{0.53}\hbox {Ga}_{0.47}\)As bulk n-MOSFETs due to the low effective mass and high permittivity. This charge control reduction induces the degradation of short channel effects. In double-gate structures, different improvements of drain induced barrier lowering (DIBL) and subthreshold slope (SS) are seen. The double-gate structure is effective in the suppression of DIBL for all channel materials. The SS degradation depends on channel materials even in double-gate structure.     

Optimal configuration analysis for acampus microgrid—a case study

The foremost issues of 21st century are challenging demand of electrical energy and to control the emission of Green House Gases (GHG) emissions. Renewable energy resources based sustainable microgrid emerges as one of the best feasible solution for future energy demand while considering zero carbon emission, fossil fuel independency, and enhanced reliability. In this paper, optimization and implementation of institutional based sustainable microgrid are discussed based on cost analysis, carbon emission, and availability of energy resources. Various microgrid topologies are considered for addressing the most ideal solution. The metrological data such as irradiance is acquired from solar satellite data of NASA (National Aero Space Agency) while the data for wind speed is taken from synergy enviro engineer’s site. HOMER® simulation tool is used for modelling and optimization purpose.     

Unified simulation of transport and luminescence in optoelectronic nanostructures

Computer simulation of microscopic transport and light emission in semiconductor nanostructures is often restricted to an isolated system of a single quantum well, wire or dot. In this work we report on the development of a simulator for devices with various kinds of nanostructures which exhibit quantization in different dimensionalities. Our approach is based upon the partition of the carrier densities within each quantization region into bound and unbound populations. A bound carrier is treated fully coherent in the directions of confinement, whereas it is assumed to be totally incoherent with a motion driven by classical drift and diffusion in the remaining directions. Coupling of the populations takes place through electrostatics and carrier capture. We illustrate the applicability of our approach with a well-wire structure.     

Multiscale simulation of MOS systems based on high-κ oxides

We report on a multiscale simulation approach that includes both macroscopic drift-diffusion current model and quantum tunneling model. The models are solved together in a self-consistent way inside a single simulation package. As an example, we study the subthreshold transfer characteristics of MOS transistors based on high-κ oxides. We compare the high-κ gates based on HfO₂ and ZrO₂ with a SiO₂ gate of the same equivalent thickness and show the effect of the tunneling current on transistor performance.     

Data reduction of power quality disturbances—a wavelet transform approach

In this paper, application of a wavelet transform approach for the data reduction of power quality disturbances is proposed. In this approach, we extracted the difference signals between the original signal and the reference waveform by a subtractor. These extracted signals were then compressed through wavelet transform methods. In this way, the amount of data was shown significantly reduced. The data transmission and storage capability can be also enhanced. We have investigated towards the reduction of various power quality disturbance data by the proposed method. Test results demonstrated the effectiveness of the method for the applications.     

VSP5-15JSAT真空自动配电负荷开关的操作与运行

近几年来，配网自动化技术的应用和发展已成为各供电企业较为关注的热点问题。早在1997年，市北供电局就开始了配网自动化的试点工作。当时选择的是电流型的重合器，在两条10kV馈线上安装了2台分段重合器和1台联络重合器，组成了一个简单环网。但随后的运行情况表明，因10kV系统中性点接地方式、网络结构、重合器保护定值多级配置等因素上的差异和影响，电流型重合器不适用于我局。     

The “Torus-Flux” motor — a novel permanent magnet synchronous machine

An ironless permanent magnet synchronous machine with a toruslike armature is presented and its inverter-fed motor performance is discussed. The calculation of the three-dimensional flux density distribution is accomplished by analytical and numerical methods. Test motor experimental results are used to check these calculations. A comparison with permanent magnet motors with cylindrical rotor and surface mounted magnets shows that for the same rated data the Torus-flux motor needs a higher amount of magnetic material and armature copper.Eine eisenlose permanentmagneterregte Synchronmaschine mit einer torusähnlich geformten Ständerwicklung wird vorgestellt; ihre Eigenschaften als umrichtergespeister Motor werden erläutert. Die Berechnung der dreidimensionalen Feldverteilung wird sowohl analytisch als auch numerisch durchgeführt. Die Berechnungsergebnisse werden mit Meßdaten eines Versuchsmotors überprüft. Ein Vergleich mit permanentmagneterregten Synchronmotoren mit herkömmlichem Zylinderläufer und Luftspaltmagneten zeigt, daß der Torus-Fluß-Motor für dieselben Bemessungsdaten mehr Magnetmaterial und Wicklungskupfer benötigt.