定时限过电流保护与反时限电流保护的计算与配合

定时限过电流保护与反时限电流保护的计算与配合谭家武（四川省泸州市电业局６４６０００）定时限过电流保护与反时限电流保护的整定配合计算比较简单，保护也容易配合；而定时限过电流保护与反时限电流保护之间的配合，相对来说复杂一些，但在配电网络中常常碰到此类问题...     

对小水电站反时限过流继电器的简易调试

农村小水电站二次保护回路整定,是电气设备安全运行的关键之一。目前小型水电站低压发电机电气控制大多数是用PKF盘为主控盘,本盘保护装置的目的只限于GL型反时限过流或速断,作用于DW空气开关,鉴于其保护装置少,且对保护整定没有正规调试,致使多数电站二次回路保护未能充分发挥,本人拟提出一个小水电站用自制水阻器对反时限过流继电器的简易调试方法,供大家参考。     

三端口光纤差动保护的调试及维护

对于T接线路的常规距离、零序由于整定困难,不易配合,而三端口光纤差动保护以其无可比拟的可靠性、选择性广泛应用于T接线路的保护。该文对三端口差动保护的维护及调试做了重点阐述。     

小型水电站变压器差动保护现场调试

水电站主变压器是联接电网和发电厂的重要设备,对它进行保护、监控是保证电厂安全稳定运行、提高经济效益的必要手段。差动保护又是变压器的主保护,它性能的优劣直接影响到变压器的正常运行,而对变压器差动保护系统进行调试是发现问题的重要手段,所以差动保护的调试是一项非常重要的工作。     

农网变电所重合器与各类开关设备的配合

近年来,随着配电自动化和配电网规划课题的提出,越来越多的配电自动化开关设备（如重合器、分段器等）上网运行,由于它们在结构、性能上与传统开关设备不同,它们之间以及与传统开关设备的配合上与传统保护相比也就有所不同。１　重合器与反时限保护的配合现在农网变电所的一般保护模式是主变高压侧采用熔断器,低压侧采用重合器,线路采用重合器与分段器。熔断器和重合器都具有反时限的保护特征而又不同于传统的反时限保护,现以黑狼口变电所进行说明。１１　基本情况被保护变压器规格：ＳＺ７—５０００ｋＶＡ　３５／１０５ｋＶ　…     

断路器越级跳闸的原因及处理

正1断路器越级跳闸的原因(1)断路器保护定值整定不当。下一级的整定电流值比上一级的整定电流值高,当下级发生故障时,断路器没有动作,而上一级的断路器发生动作。(2)断路器的上下级保护时限配合不当。下一级的保护时限应当比上一级的保护时限要短。如果两者的保护时限设定相反就会发生越级跳闸。     

基于ETAP软件的反时限定值分析

某高压电机起动时发生过流保护跳闸,根据DL/T 584-2017《3 kV～110 kV电网继电保护装置运行整定规程》校核保护定值计算符合要求;采用ETAP软件进行定值配合检查,找出REF542plus保护装置内反时限曲线类型设置错误是造成电机起动失败的原因。     

箱式直流电源在小型变电所的应用

对10kV单路供电容量在2000kVA以下的变电所，通常称为小型变电所，已往对于这一类变电所常采用交流操作、反时限的过电流保护。其优点是没有辅助设备，占地面积小，其缺点是过电流保护的准确性不高，以及反时限与供电线路上一级的定时限过电流保护不易配合。尤其是近年来中小企业发展很快，这类变电所数量不断增加，现有企业不断扩容，     

变电工程中变压器安装调试的注意事项

变压器是变电工程的核心装置，其安装调试效果直接影响着输变电质量。文章从某110 kV变电站运行过程中变压器的故障缺陷出发，研究变电工程中变压器本体吊装流程及附件安装操作，在安全标准及技术规范基础上，优化安装技术及调试流程，以保障110 kV变电工程主变压器安全、可靠、稳定运行。     

ZKD—1型系列多功能综合馈线保护装置简介

一、概述 ZKD—1型系列多功能综合馈线保护装置是采用国际先进线路保护技术针对我国农网状况而设计的多功能高压柜保护。其功能与常规继电器相比,可取代四台电流继电器,两台时间继电器,两台反时限过流继电器,一台欠电压继电器（或一台接地保护或一台三相一次重合闸装置）和一台信号继电器。 装置采用集成电路元件。时间及定值整定均采用8421数字式拨轮开关;反时限采用集成VF芯片;过流及速断信号能自保持,便于观察记录,并具有远方发讯功能;过电流保护可由面板开关选择定时限或反时限。装置具有高可靠性,高精度,抗干扰能力强,调试简便,操作使用灵活方便和体积小、功耗低等特点。与分立安装的继电器相比较,开孔少,配线大为简化,价格低,功能强,是目前高压柜及110kV以下电压等级线路二次保护的首选产品。 装置配置如表所示     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

农村剩余劳动力就业问题的探讨

论述了我国农村剩余劳动力就业的意义，并针对我国农村剩余劳动力的现状，提出多渠道促进农村剩余劳动力就业的途径和办法。     

车用发动机润滑油失效规律与更换周期研究

研究在正常使用条件下１０Ｗ／３０－ＱＣ级润滑油用于某型车用发动机时所表现的失效规律,确认期服从两参数Ｗｅｉｂｕｌｌ分布,并给出分布的尺度参数η和形状参数ｍ之最佳线性无偏估计（ＢＬＵＥ）同时,还为定量分析,计算车用发动机润滑油的使用可靠性和合理确定其更换周期提供了一套可供借鉴的方法,并给出了具体的计算实例。     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

乡（镇）农业技术推广体系存在的问题及对策

乡（镇）农技推广体系是农业发展的关键。介绍朝阳市农业技术推广体系的现状,针对目前体制及运行机制、服务手段等方面存在的问题,提出适合朝阳市乡（镇）农技推广体系改革与发展的对策,以期对全省农技推广体系改革和发展起到一些借鉴作用。     

草莓的采收与贮藏

草莓果味酸甜爽口,营养价值高,为人们所喜爱的应市鲜果之一。由于草莓易受损伤和微生物侵染,因此其采收、贮藏过程极为重要。介绍草莓采收过程中的注意事项以及11种贮藏保鲜技术的实施步骤和操作方法,推介9种加工方式,为草莓产业化提供技术支持。     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.