陈建平,崔伟,吴晓东,张雪
(松辽水利委员会水文局嫩江水文水资源中心,黑龙江齐齐哈尔161000)
[摘要]文中介绍了嫩江右侧主要支流水情自动测报系统的概况,重点论述了超短波通信实时传送水位数据的原理及方法,详细分析了超短波通信在实际应用中存在的问题,最后提出了相应的改进方案。
[关键词]嫩江支流;水情测报;超短波通信;改进
水文信息的采集与传输对防汛抗旱、水资源管理、生态与环境保护等水情工作非常重要。目前,水文数据传输的方式主要包括有线方式和无线方式。有线通信方式常受到地形地貌、通信距离、布线条件和布线成本等因素限制,而无线通信方式相对比较灵活。由于嫩江流域有些站处在偏远山区,所以采用无线通信。
超短波通信方式目前在国内外水利信息通信系统中被普遍使用,尤其在本地区或局部地区非常有效,另外超短波系统的设备全部由拥有者管理,不受其他单位约束,通信速率可自己决定,所以超短波在水文信息采集上的地位仍然很重要。例如,现在市场上日本精工的数传电台ND250A,数传频率范围223~235 MHz,符合水利行业规定的频段和带宽,满足水情信息数据实时传输要求。
嫩江右侧主要支流水情自动测报系统主要由1个中心站、4个分中心站、90个遥测站(78个雨量站、12个水文站)以及2个数据上传站构成。该系统按星型网络结构设计,采用GSM/北斗混合通信组网方式,中心站接收系统所有测站数据,分中心站接收各自所在地区测站数据,遥测站采用一点多发或一发多收的运行机制,即遥测站同时向中心站和所在地区分中心站发送数据,数据上传站采用GPRS信道发送到中心站。
在该系统中,个别水文站因水位观测井距水文站房距离较远,一般在几公里以内,不具备有线传送水位数据条件,所以遥测设备采取分别安装在站房(主站)和测井(从站)两处,二者之间采用超短波通信方式进行数据传输。在水利系统水文监测中,超短波通信的频率一般在230 MHz,这一频段的通信质量好,传输信号也比较稳定,而且有一定的绕射能力,可以避过大部分树木或房屋的阻挡,从而实现主从站间数据通信。
2.1 通信架构
采用日精ND250A数传电台构建超短波通信系统,由主站和从站两部分组成。主站包括RTU、GSM模块、北斗卫星电台、ND250A数传电台、数传电台适配器、直流电源等设备,从站包括RTU、GPS模块、ND250A数传电台、上电控制器、直流电源等设备。
由于数传电台功耗较大,为节省电能平时不上电,电台不工作,当从站有数据流时(一般设定水位变化为0.01 m)才上电工作,主站电台采用常供电。在无线传输过程中采用握手通信方式实现数据传送,即从站发送完毕后等待主站的回执信号,若收到回执信号,则从站对电台断电通信结束;否则进行第二次数据发送,以此类推。在从站未收到回执信号的情况下,每个信号最多发送3次。主站电台在收到并解码数据后,将数据送给适配器,适配器将数据保存下来,当主站开始采集水位数据时发送给RTU,水位数值达到设定阈值后(一般设定水位变化为0.03 m),通过远程通信信道(GSM或者北斗卫星)发送至分中心站和中心站。
2.2 性能分析
采用超短波通信的水文站在实际运行过程中主要出现采集的水位数据不变,由于整个超短波通信系统设备组成较多,出现此类故障的原因也比较复杂,需要对采集的水位数据、设备的供电状态、通信的交互连接等情况作出研判,从而定位故障点,查明故障原因。但从长期运行维护监测数据来看,发生故障的原因主要是主从站两边的时钟不同步,主站采用北斗卫星校时,从站采用GPS校时,由于卫星资源时常被占用,造成每次校时耗时长,校时困难,这给系统运行维护工作带来很大不便。所以如何保证主从站两边需要传送数据时时间窗口能够达到一致,变得尤为重要。
2.3 改进方案
为使水位数据报送能够更加及时准确,通过近几年对整个超短波通信系统设备原理学习和实际运行维护过程的经验总结,现提出以下几项改进方案:
1)从站数传电台供电可以由有数据流时上电改为长供电,必要时可以改为较大容量的蓄电池,以提供长时间供电,保证电台时刻准备传送数据,以此避免由于主从站时间窗口不同步,与主站建立通信连接时,从站电台仍处于断电状态,造成数据通信失败。
2)因主从站数据采集时间间隔为每6 min一次,所以可以增大主站电台收信时间窗口,使从站发信时间窗口在主站时间窗口之内,预留出因通信不畅从站重复发送数据时间,使主站在时间窗口内接收从站发来的数据。
3)可以将水文站从站设备RTU更换为采用2.4G无线短传技术设备,在安装调试时只需主站进行时钟校时,从站会在每隔6 min自主与主站建立通信连接,此时进行时钟校时,保证主从站时钟同步,使水位数据正常传送主站。
在实际应用中,我们已经对个别水文站进行了改进,并取得了良好的效果。
超短波通信因其通信质量好、传输信号比较稳定、适宜短距离数据传输等优点,在嫩江右侧主要支流水情自动测报系统水位数据传送中发挥重要的作用。通过对超短波通信相关设备的改进,不仅减少了时钟校时带来的工作量,也使水位数据报送能够更加及时准确,极大提高了嫩江流域洪水预报精度,为嫩江及松花江流域的防汛工作提供重要水文数据支撑。
[Abstract]The K-means cluster analysis is used to identify the category of the water quality monitoring section in buffer zone of provincial boundaries of Songhuajiang basin.The analysis results show that the 51 water quality monitoring sections are divided into 7 categories and the optimization analysis is made for the monitoring sections of each category.Based on the natural attributes including the nature geographical location and the optimization principle of monitor index,the former 51 monitor sections are reduced to 39 in buffer zone of provincial boundaries of Songhuajiang,the 12 sections are streamlined,which could reduce the monitoring workload and save the monitoring costs.
[Key words]Songhuajiang basin;buffer zone of provincial boundaries;monitoring section;classification analysis
Design of sand protection and sand fixation measures for water conveyance open channel crossing desert
WANG Feng
[Abstract]The key point of biological protection sand fixation is finding out the some situations as the basis of the protective design, including the terrain,the geomorphy vegetation status and the scope of protection zone in the project area,the wind gap,the main wind direction in different area and the cause and harm of the quicksand.The desert plants are exposed to the surface of the mobile sand in the initial stage,the wind erosion is serious and fixed survival is hard.The unique characteristic of the desert plant is used to forming the horizontal network foot system with tens of meters in the short term,which could weaken the movement of quicksand and reach the purpose of stabilizing sand soil surface.
[Key words]water conveyance open channel;cross desert;sand protection and sand fixation;design
Scheme demonstration of dam site of Watuo hydropower station in Jinheriver of Tibet
QI Li-wei,DU Xing-yang,NING Wei-qi
[Abstract]The optional range of dam site of Watuo hydropower station is about 5.73km long river from the end of Jinhe hydropower station reservoir to the lower reaches of the site of The Lezhu hydropower station.The paper analyzes and demonstrates comprehensively the dam site of Watuo hydropower station from the topography and geology condition,the project layout,the division layout,and so on.The final selection of the dam site is located at downstream 2.5km of Jinhe river in Lieba village of Karuo district of Changdu city.
[Key words]Watuo hydropower station;dam site;scheme demonstration
Application of form in underwater concrete casting construction
CAI Guang-zhe,LIU Zhan-jun,LIU Hai-fu,HAN Chuang
[Abstract]Theintegralnonformstrippingcansolvemanycommonproblemsexistingintheunderwaterconcretecastingconstruction, including the poor stability of form supporting,the poor tightness,the poor integrity,the large underwater workload,the poor quality of concrete casting appearance,and so on.The application of integral non form stripping in underwater concrete casting construction could improves the project safety and saves the project cost,which has a good application prospect for the underwater concrete casting aspects with the complex dimension complex,the high dimension accuracy and the short construction period.
[Key words]form;underwater concrete casting;application
Analysis of concrete temperature control and crack prevention measures in Sanwan hydraulic project
HUANG Ju
[Abstract]According to the high requirement of temperature control and crack prevention measures in severe cold area,combining with the concrete construction of Sanwan hydro-junction project in Liaoning province,the paper studies the standard and demand of temperature control design in the concrete construction by using the numerical simulation software,obtains the rational casting thickness of concrete and the standard of the temperature control in different position,and introduces the specific temperature control and crack prevention measures for the project.The project practice has proved that,the concrete construction with the temperature control and crack prevention measures achieves the anticipated effect basically and the hazardous temperature cracks did not appear.
[Key words]concrete;temperature control;crack prevention measure
Analysis of mechanics and durability performance of rubber particle concrete
SHEN Chang-yue,LI Xiao-lin
[Abstract]The addition of rubber particles in concrete could effectively improve some properties of concrete.Through the orthogonal experiment with the three factors and three levels,the paper analyzes the development laws of mechanics performance and durability performance for the rubber particles concrete and compares the differences with the reference concrete.The test results show that, after the rubber particles are incorporated into the concrete,the compressive strength,the bending strength and the elastic modulus of the concrete are decrease,but the impermeability,frost resistance and abrasion resistance are increase significantly.Considering the mechanics performance and durability performance of rubber concrete,the rubber particles content of rubber concrete should be controlled within15±5%.
[Key words]rubber particles concrete;mechanics performance;durability performance
Study on layered water intake water temperature numerical simulation for Fengman reconstruction project
LIU Feng,DONG Yan-chao,ZHANG Zi-qi,ZHOU Rong-lei
[Abstract]The statistical information shows that the layered water intake facilities are set to control the water intake area,which could improve effectively the water temperature of water discharge.Through the establishment of three dimensional water temperature mathematical model,the paper further studies the relationship of water intake temperature and water intake elevation of inlet of the layered water intake for the stop logs gate and demonstrates the effect of layered water intake according to the water temperature vertical distribution of typical month in rainy year,dry year and the normal year.
[Key words]layered water intake;water temperature;numerical simulation;Fengman hydropower station
Frequency calculation of lowest tidal level of Yingkou station
NI Wan-nan,CHEN Li-xiang,GU Hong-liang,WANG Jing-jing
[Abstract]By analyzing the corresponding relationship of the statistic parameters between the lowest tidal level(negative value series) and the highest tidal level(positive value series)in the Pearson-III type distribution,the paper finds out the calculation method of the lowest tidal level,calculates the design lowest tidal level of Yingkou station and estimates the design lowest tidal level by using the extreme-I distribution.At last,the rational design value of the lowest tidal level is selected.
[Key words]design tidal level;frequency calculation;Yingkou station
Classification analysis of water quality monitoring section in buffer zone of provincial boundaries of Songhuajiang basin
PENG Jun,LIU Hong-chao,ZHENG Guo-chen,JIANG Hou-zhu
[中图分类号]TV123
[文献标识码]B
[文章编号]1002—0624(2017)08—0069—02
[收稿日期] 2017-02-22
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