中小型发电机组灭磁电阻与磁场断路器的选配

灭磁就是把励磁绕组中的磁场储能尽快地减弱到尽可能小的程度。对灭磁电阻的参数选择与磁场断路器型号选择、配合有一定的要求，否则不能达到快速灭磁的目的。叙述了灭磁原理和线性电阻，非线性电阻与磁场断路器的选配原则。图3幅，表1个。     

发电机磁场断路器柜烧毁事故原因分析及改进意见

１９９９年某大型水电厂曾发生一起发电机励 磁系统磁场断路器柜烧毁事故，分析其原因是：ＤＭ４型双断口磁场断路器的开断弧压太低，保证不了因励磁装置失控而导致发电机误强励到最大值时转子电流向氧化锌灭电阻转移。由于该电厂的其他机组及其他电厂的类似机组也存在同样问题，因此类事故仍有可能继续发生。     

发电机磁场断路器分断能力的选择

针对发电机灭磁系统在实际运行中出现的问题，对磁场断路器在发电机的各种灭磁工况下所承受的电流，电压进行了分析计算，提出磁场断路器的额定分断能力应按满足电站发电机在所考虑的严重灭磁工况下的灭磁要求进行选择。     

高能氧化锌电阻及双断口磁场断路器在同步发电机灭磁系统中的…

本文就前几年发电机灭磁及过电压存在的问题和解决方法进行了探讨，并就高能氧化锌电主双断口磁场断路器的应用提出了自己的看法。     

IGBT开关励磁应用前景分析

从理论和初中两个方面分析了ＩＧＢＴ开关励磁相对可控硅励磁的优势及存在问题，分析了前者的应用前景。     

IGBT开关励磁的原理及应用

本文给出了新型功率半导体器件（ＩＧＢＴ）的基本特性和驱动方法，及其工作在开关状态下的功率损耗计算方法。同时讨论了ＩＧＢＴ在开关励磁中的应用和原理，给出了开关励磁磁磁装置的基本输出输入关系。最后，本文指出相对于可控硅励磁，开关励磁在控制和驱动方面具有突出的优点。     

DM4磁场断路器的维修与试验

本文叙述了ＤＭ４型磁场断路器主触头接触电阻过大和合闸机构稳定性不够的原因与解决方法，，及其修后的试验项目。     

巴基斯坦T电站磁场断路器参数设计与选型研究

巴基斯坦T电站机组单机容量大、励磁参数高,对磁场断路器的参数要求也非常高。为了确定磁场断路器的参数要求,给磁场断路器选型设计提供量化理论依据,采用定性分析与定量计算相结合的研究方法,对巴基斯坦T电站可能出现的各种故障类型和相应的灭磁工况,以及各种灭磁工况下的转子电压和转子电流进行了分析、计算和研究,进而确定磁场断路器的参数要求。通过对具有高分断能力的Gerapid 4207 2X2和CEX 06 5000 4.2开关的比选分析,发现Gerapid 4207 2X2开关能满足巴基斯坦T电站发电机事故灭磁分断要求。     

水电站设置发电机断路器的探讨

水电站需要倒送厂用电且接有公共厂用变压器的单元回路，开、停机频繁的调峰水电站，联合单元回路，扩大单元回路，三线圈变压器或自藉变压器回路，在发电机出口处均宜装设断路器。其优点是：适应调峰；提高厂用电供电可靠性、灵活性；减小故障范围、增大保护的选择性；适于同期操作；随着发电机断路器集成化，可简化设计、利于布置。在比较断路器的装设方案时，应考虑价格、机械寿命（无故障操作次数）、故障率、供电可靠性及电站回报率因素，应重视电站经济性的动态评估。     

A FIELD TEST DATA RESEARCH BASED ON A NEW HYDRAULIC PARAMETERS QUICK TEST TECHNOLOGY

The hydraulic parameter quick test system in accordance with the oscillation principle can overcome the shortcomings of traditional methods in determining hydraulic parameters which, besides having complex hydrogeological restrictions and needing complex equipment in the field, are often both time and energy consuming, and high cost. Based on the hydrogeological conditions in the north anchorage of Taizhou Yangtze River Highway Bridge, a quick hierarchical test is carried out for different depths of single-hole drilling to verify the function of the system in this case. Meanwhile, with a purification of the raw data gathered in the test by wavelet denoising, the hydraulic parameters are worked out by adopting the Kipp model. A comparison between the Kipp model results and stratigraphic data as well as pumping test results justifies the reliability and accuracy of the new method. The study finds other advantages of the method like high efficiency in operation, flexibility in stratified test, as well as environmental-friendliness. Therefore, the technology is of significant practical value and application prospect.     

SILCO5静止励磁系统灭磁回路的计算和分析

0 引言SILCO5微机静止自并励励磁系统是GE公司比较成熟、可靠性高的定型产品,GE公司将其作为巨型发电机的最理想的配套励磁系统.其主要功能有:最大励磁限制、最小励磁限制、电力系统稳定器、转子过电压保护、发电机转子I2T保护、电压互感器断线保护等.由于其运行可靠、性能优良、功能齐备,国内已有二滩、隔河岩、刘家峡等巨型水电站选用该系统.随着GE公司被三峡工程中标,SILCO5微机静止自并励励磁系统将可能和GE公司的巨型发电机配套,出现在世界上最大的水电站中.但我们通过计算和分析发现,其灭磁回路的设计有较大缺陷.本文以二滩设备为例对此加以分析.     

CALCULATION OF FLOW FIELD AND ANALYSIS OF SPAWNING SITES FOR CHINESE STURGEON IN THE DOWNSTREAM OF GEZHOUBA DAM

The Chinese sturgeon (Acipenser Sinensis) is one of the unique and important fishery resources in China. Since the construction of the Gezhouba Dam, the traditional migration route of the sturgeon has been blocked; consequently, the length of natural spawning sites is reduced from 800 km in the past to less than 5 km at present. As an endangered species, the Chinese sturgeon has become one of the most conserved aquatic species. In this article, the flow field of its spawning states in the downstream of Gezhouba Dam was simulated and analyzed using N-S equations and k ? ε turbulence model. Volume Of Fluid (VOF) method with the Finite Volume Method (FVM) was used to simulate the water-air two-phase flow to examine the computed area. On the basis of the ecological-hydraulic characteristics of Chinese sturgeon, the features of the flow field were investigated to provide theoretical support for the proper management of the Three Gorges Reservoir.     

EXPERIMENTAL MEASUREMENT AND NUMERICAL SIMULATION FOR FLOW FIELD AND FILM COOLING EFFECTIVENESS IN FILM-COOLED TURBINE

Numerical simulation of three-dimensional flow field and film cooling effectiveness in film-cooled turbine rotor and stationary turbine cascade were carried out by using the k - ε turbulence model, and the predictions of the three-dimensional velocities were compared with the measured results by Laser-Doppler Velocimetry (LDV). Results reveal the secondary flow near the blade surface in the wake region behind the jet hole. Compared with the stationary cascade, there are the centrifugal force and Coriolis force existing in the flow field of the turbine rotor, and these forces make the three-dimensional flow field change in the turbine rotor, especially for the radial velocity. The effect of rotation on the flow field and the film cooling effectiveness on the pressure side is more apparent than that on the suction side as is shown in the computational and measured results, and the low film cooling effectiveness appears on the pressure surface of the turbine rotor blade compared with that of the stationary cascade.     

THE EFFECT OF OIL CAVITY DEPTH ON TEMPERATURE FIELD IN HEAVY HYDROSTATIC THRUST BEARING

For a heavy hydrostatic bearing with a high linear velocity,the results of numerical calculations often differ from practical conditions if the viscosity is considered as constant.In this article,the influence of the oil cavity depth on the temperature field in the heavy hydrostatic bearing is discussed in the context of variable viscosity.The viscosity-temperature relations for the gap oil film are first established by fitting B-Spline curves,then,numerical calculations for the temperature field in the heavy hydrostatic bearing of different oil cavity depths are carried out based on Finite Volume Method (FVM) under the same rotating speed,and the influence of the oil cavity depth on the temperature distribution in the gap oil film of the hydrostatic bearing is discussed.The results of numerical calculations provide the temperature distribution state inside the hydrostatic bearing,which would help the selection and the design of hydrostatic bearings in engineering practice.     

A LATTICE BOLTZMANN METHOD FOR SIMULATION OF A THREE- DIMENSIONAL DROP IMPACT ON A LIQUID FILM

A single-phase free surface tracking model based on the Lattice Boltzmann Method （LBM）, which has capability of simulating liquid-gas system with the assumption that the gas phase has only negligible influence on the liquid phase, is utilized to simulate the flow of a drop impacting on a liquid film. Three typical outcomes in the flows, i.e., deposition, crown and splash, which have been observed in the previous experiments, are obtained in the present three dimensional numerical simulations. The numerical results are consistent with the experimental and analytical results available.     

基于关系数据库的土石坝病险智能诊断专家系统设计

土石坝病险智能诊断专家系统的研制和应用对于土石坝的安全运行意义重大。文中介绍了利用ActiveX数据对象（ADO）数据库访问技术，结合关系数据库与规则库，实现基于关系数据库的土石坝病险智能诊断专家系统的设计方法。     

EXPERIMENTAL AND NUMERICAL STUDY FOR HYDRODYNAMIC CHARACTERISTICS OF AN OSCILLATING HYDROFOIL

The present article reports the experimental Particle Image Velocimetry （PIV） investigation and the corresponding numerical simulation results about the water flow over the oscillating hydrofoil and its unsteady dynamic characters. The experimental study focuses on the effect of mean angles of attack. The comparison between the PIV results and numerical prediction about the flow field using Fluent well demonstrates the capability of CFD on the simulation of the water flow around the pitching hydrofoil. The numerical results indicate that the forced oscillating frequencies have evident effects on the flow separation and vortex shedding. The simulations about the hydrodynamic drag and lift coefficients were also performed.     

基于GIS与数学模型集成的闸泵信息管理系统

为了满足科学、合理、充分、有效地调度现有水利设施（包括水闸、泵站等），以达到防汛、除涝、控制水源、改善水环境的目的，对基于地理信息系统（GIS）与数学模型集成的闸泵信息管理系统进行了研究与开发。文中介绍了该系统的基本功能、设计及具体实现。用数据库管理闸泵信息管理系统的空间数据和属性数据，同时利用GIS完成对地图的显示、编辑、打印等功能。