750 kV超高压输电线路对共用走廊并行配电线路三相电压不平衡的影响分析及治理措施

受750 kV输电线路电磁感应影响,35 kV配电线路并行接近共用走廊的750 kV输电线路时,35 kV配电线路会出现三相电压不平衡问题,严重时会引起35 kV输电线路继电保护装置动作,影响该线路的运行可靠性,目前国内外针对该问题的治理措施报道较少。分析了并行段内不同电压等级导线间的距离、高度、并行长度等参数对35 kV线路三相电压的影响程度,提出了降低35 kV配电线路对地高度并加装屏蔽地线,在35 kV配电线路上加装并联电容器,在35 kV配电线路上加装并联电抗器等保护措施,研究结果表明,采用上述措施可有效改善35 kV配电线路三相电压不平衡问题,提升了配电线路运行可靠性和抵御电磁影响的能力,为750 kV和35 kV线路共用走廊段线路的设计标准制定提供参考方案。     

干式空心并联电抗器截流投切过电压分析

近年来,35kV电网中真空断路器开断并联电抗器时发生了多起事故,而干式空心电抗器故障多数是匝间绝缘缺陷造成匝间短路引发的,因此干式空心电抗器匝间绝缘问题已经越来越被重视。由真空断路器分闸引起干式空心并联电抗器过电压对电抗器的匝间绝缘老化起到了至关重要的作用。基于上海某变电站实际电气主接线,构建投切35kV并联电抗器单相模型以及三相模型,并且考虑到三相模型中另外两相的工频电源对首开相产生的影响,计算由断路器分闸产生的最大截流过电压达到7.3(标么值)而同时开断三相电抗器时产生的最大截留过电压高达8.6(标么值)。     

220kV变电站35kV侧真空断路器开断并联电抗器过电压保护方案研究

针对多次发生35 kV真空断路器开断并联电抗器引发过电压事故的某220 kV变电站,建立了基于ATP-EMTP的电磁暂态模型,介绍了三星型避雷器、组合式四星型避雷器和RC阻容吸收器这3种不同的保护装置,仿真分析计算了将这3种保护分别各自安装在35kV母线、断路器负荷侧和并联电抗器侧时的过电压.研究结果表明,三星型避雷器几乎无法限制相间过电压,组合式四星型避雷器对相间过电压有一定的限制作用,RC阻容吸收器对相间过电压的限制效果最好,而单独安装一种保护装置无法同时有效抑制各处的过电压.     

一起35k V干式电抗器故障原因分析

针对某500 kV变电站发生的一起35 kV电容器组串联电抗器在运行中发生起火故障,分别从返厂解体检查、试验情况进行了综合分析,查找出故障原因为电抗器最内层包封匝间绝缘裂化造成匝间短路、过热引发设备起火故障,并从原材料及生产工艺方面深入分析了设备存在的设计、制造缺陷,提出该类设备的日常检修、维护建议和改进措施.     

电力系统谐波背景下10kV串联铁芯电抗器噪声分析

基于嘉定地区电网谐波背景下一起10kV串联铁芯电抗器噪声过大缺陷处理,分析电力系统谐波对10kV串联铁芯电抗器噪声的影响,为今后10kV串联电抗器设计选型提供依据,避免由于电抗器选型不妥导致的噪声超标问题。     

66kV干式空心电抗器接地扁铁发热分析及处理

66 kV干式电抗器在750 kV系统电网中对消纳充电功率起着重要的作用,为了保证其正常运行,确保电力系统稳定运行,对新疆乌北750 kV变电站66 kV干式空心电抗器接地扁铁发热现象及时进行了分析,诊断发热的主要原因是在漏磁范围内存在闭合回路。通过改变连接接地支柱的方式,打开此闭合回路,解决了66 kV干式空心电抗器接地扁铁发热问题。     

1 100 kV特高压直流输电工程平波电抗器温升试验

±1 100 kV特高压直流是我国正在研究的一个全新输电电压等级,而平波电抗器是直流输电的核心设备之一,故研究平波电抗器的性能意义重大。以国家电网公司拟定的±1 100 kV准东—重庆直流输电工程的平波电抗器技术规范为依据,介绍了±1 100 kV特高压直流输电用干式空心平波电抗器温升试验方法及过程,并分析了平波电抗器样机温升试验数据。结果表明,该平波电抗器满足技术规范中对平均温升和热点温升限值的要求。研究成果为1 100 kV电压等级下直流输电项目的研发提供了技术保障,也为该电压等级下平波电抗器的工程应用奠定了基础。     

分析35kV串联电抗器着火原因及预防措施

串联电抗器着火事件时有发生,严重威胁电网的安全稳定运行。本研究对比分析了500kV变电站35kV串联电抗器在不同接线方式下的特性,以及在不同情况下串抗着火时的保护动作情况。针对着火事件,我们提出了有效的灭火处理方案,旨在协助运维人员快速隔离故障,确保其他设备正常运行。此外,我们还提出了一系列预防措施,以降低着火事故的发生概率,并探讨了快速发现串抗着火的应对措施,帮助运维人员及时探知事故并将其影响范围降至最低,为串联电抗器的运维管理提供了重要参考依据。     

官亭变电站750 kV高压并联电抗器运行状况分析

官亭变电站750 kV 2#电抗器是国内目前运行电压等级最高的一组高压并联电抗器。分析了750 kV高压电抗器在官亭变电站的运行情况和技术监督数据:技术监督数据稳定,油色谱分析数据良好,继电保护和安全自动装置无动作,电抗器整体运行状况良好。提出了未来改造计划:重新建造3台电抗器的基础,将目前的条形基础改为方形基础,增强电抗器的底部支持面,放弃现在使用的千斤顶;制造一台新的电抗器,替换运行中的电抗器B相。     

干式空心并联电抗器开断过程中复燃过电压研究

在35kV电力系统中采用真空断路器来开断电抗器引起复燃过电压,给电抗器的匝间绝缘造成破坏。基于上海某变电站实际电气主接线,构建投切35kV并联电抗器单相模型以及三相模型,计算出首开相产生的复燃过电压幅值为3.0(标么值)。根据后开相的过电压产生机理,计算出非工频电流过零相产生的过电压幅值为13.0(标么值),而在前两相均产生复燃的情况下,最后相产生的过电压幅值为16.6(标么值)。     

Localization of wind turbine noise using a microphone array in wind tunnel measurements

An experimental investigation on scaled wind turbine models in a wind tunnel with a microphone array is presented. Our study focuses on the localization and quantification of aerodynamic noise sources on rotating wind turbine blades with the aim of identifying the contributing factors that have an impact on the source spectra. Therefore, wind tunnel measurements were conducted for three different blade geometries (NACA 4412 shape, Clark-Y shape, and sickle shape), five pitch angles between ?2° and +8° and five wind velocities between 5 and 13 ms^??1. For the localization of rotating sound sources with a microphone array, a rotating beamforming method based on the acoustic ray method is used. The Clean-SC deconvolution method was used to improve the resolution of the acoustic sources, and integrated spectra were calculated for the individual blades. The sound sources were localized at the wind turbine blades and assigned to the leading edge and trailing edge subregions. The results show a high dependency on the sound source distribution and the source strength with regard to the observed one-third octave bands, wind velocity, and blade geometry. Hence, the localization of rotating sound sources with a microphone array is a suitable method for the development of wind turbine blades that emit less noise.     

声源辐射表面声功率的理论研究

在点声源、线声源的基础上,研究了圆形面声源、矩形面声源、半球声源、球声源、正方体声源的声强、声功率,建立了正方体声源的声学模型,并进行了声源辐射表面声功率的理论推导。表面声能分布不均匀声源的半消声室试验证明,按声强法声源辐射表面声功率理论得到的声功率计算结果与测量结果相符,从而提出了声源声功率测量理论。     

35 kV高压配电室全智能防凝露系统的开发及应用

在分析目前配电室防潮除湿设备不足之处的基础上,开发出高压配电室全智能防凝露系统。该系统由基于PLC+HMI的中央控制单元、温湿度变送器阵列及外围执行设备构成,全面考虑了配电室各个区域的防凝露需求,设计出一系列科学的控制策略,实现了除湿机停电保护、冲击电流保护、设备疲劳保护、低温保护、快速降温保护、报警信号响应等功能。产品已成功应用于35 kV高压配电室并取得了良好效果。     

Thermal‐hydraulic design features of a micronuclear reactor power source applied for multipurpose

Microheat pipe cooled reactor power source (HRP) designed for space or underwater vehicles meets the future demands, such as safer structure, longer operating time, and fewer mechanical moving parts. In this paper, potassium heat pipe cooled reactor power source system which generates 50 kWe electricity is proposed. The reactor core using uranium nitride fuel is cooled by 37 potassium high‐temperature heat pipes. The shields are designed as tungsten and water, and reactor reactivity is controlled by control drums. The thermoelectric generator (TEG) consists of thermoelectric conversion units and seawater cooler. The thermoelectric conversion units convert thermal energy to electric energy through the high‐performance thermoelectric material. A code applied for designing and analyzing the reactor power system is developed. It consists of multichannel reactor core model, heat pipe model using thermal resistance network, thermoelectric conversion, and thermal conductivity model. Then, the sensitivity analysis is performed on two key parameters including the length of the heat pipe condensation section and the cold junction temperature of the TE cell. Meanwhile, the steady‐state calculations are conducted. Results show that the maximum fuel temperature is 938 K located in the center of reactor core and the outlet temperature of coolant reaches 316 K. Both of them are within the limitation. It is concluded that the preliminary design of HPR design is reasonable and reliable. The designed residual heat removal system has sufficient safety margin to release the decay heat of the reactor. This research provides valuable analysis for the application of micronuclear power source.     

An Experimental Study on Aerodynamic Sound Generated from Wake Interference of Circular Cylinder and Airfoil Vane in Tandem

The purpose of this study is to investigate the characteristics of aerodynamic sound generated from wake inter-ference of circular cylinder and airfoil vane located in tandem and to clarify the generation mechanism of thesound source with discrete frequency.The effects of the interval between the cylinder and the airfoil on the char-acteristics of aerodynamic sound are investigated by acoustic measurement,flow visualization and explorationtest of sound source.The relation between the flow field and the sound field with discrete frequency noise(DFN)is shown,and then it is found that the downstream airfoil works as the sound source of DFN,which has the fre-quency of vortex shedding from the upstream cylinder,when the interval of two bodies is longer than a criticaldistance.     

用于特/超高压电网电压控制的分级

结合国内某规划的750 kV输变电工程,采用分级投切式可控高抗对电网的电压进行控制,提出了750 kV分级投切式可控高抗的控制策略,基于电力系统分析计算软件（BPA）仿真,验证了该控制策略实现智能动态调节电网电压的实用性。     

4缸柴油机怠速噪声及声品质优化研究

针对高压共轨4缸柴油机进行了怠速噪声测试、噪声源识别、降噪以及声品质优化研究工作.通过改变转速、预喷油量、预喷间隔角、轨压和主喷正时,研究了这些参数对怠速噪声的影响,并确定最佳值.通过燃烧噪声分析和噪声源识别,采取怠速噪声降噪措施.对怠速噪声优化前后的结果进行声品质比较,采取的电控标定优化和屏蔽措施能有效改善怠速声品质.研究结果表明:该4缸柴油机经过电控优化标定后的主要怠速噪声源为机械噪声,通过对齿轮室罩盖、气缸盖罩盖等薄壁件采取屏蔽措施,能有效降低怠速噪声,改善声品质.     

Acoustic Wave Prediction in Flowing Steam-Water Two-Phase Mixture

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