基于EPOCHS的数字化变电站通信网络仿真分析

针对变电站自动化系统全站统一式通信网络结构,在电力通信同步仿真平台（EPOCHS）上建立了基于IEC 61850标准的数字化变电站的通信网络动态仿真模型。依据网络仿真需求,在网络模拟器NS2中实现了物理子网间的连接,并添加虚拟局域网多播和报文优先级处理机制。对采样值（SAV）和通用面向对象的变电站事件（GOOSE）传输的实时性进行了仿真分析,仿真结果为网络带宽、虚拟局域网划分以及报文优先级处理提供了依据。     

数字化变电站继电保护的GOOSE网络方案

根据数字化变电站继电保护的面向通用对象的变电站事件（GOOSE）需求,针对速动性分析了网络传输延时后提出了改进方法,并针对可靠性和安全性分别分析了不同冗余方式和交换机分配模式的特点。提出根据系统一次接线形式及继电保护配置特点合理规划继电保护GOOSE网络方案的方法,并给出了典型接线形式下的GOOSE网络方案。此外,应根据一次接线形式及继电保护配置特点对交换机虚拟局域网（VLAN）划分、优先级及多播报文过滤进行合理配置。     

GOOSE通信与应用

IEC 61850标准的通信模式有客户/服务器（C/S）模式和 P2P（peer-to-peer）模式2种，面向通用对象的变电站事件（GOOSE）作为IEC 61850的一个全新应用，采用了P2P模式，并应用了许多最新的网络与通信技术，使许多新的应用成为可能。文中对GOOSE通信协议栈进行了分析，并对GOOSE应用的一些关键问题进行了研究，如虚拟局域网（VLAN）的划分、时间的测试、GOOSE辅助工具等。     

基于EPOCHS平台的IEC 61850采样值传输仿真

采样值传输是IEC 61850变电站自动化系统过程层与间隔层之间通信的主要部分。在电力和通信系统同步仿真（EPOCHS）平台上提出IEC 61850变电站通信仿真框架，针对具体变电站构建IEC 61850通信模型。在NS2中添加虚拟局域网（VLAN）IEEE 802.1Q协议代码，实现VLAN多播报文的仿真。对交换式以太网和共享式以太网、接收不同数目合并单元采样值报文的保护设备进行了比较。结果表明:100 Mbit/s交换式以太网完全满足标准要求，而100 Mbit/s共享式以太网采样值报文时延和时延抖动较大，导致工频保护测量值波形畸变;接收多个采样值报文的保护设备存在链路瓶颈问题，对此提出了多通信插件的解决方案。     

变电站GOOSE报文在IED中的实时处理

报文的通信延迟包括传输延迟和处理延迟2部分。IEC 61850标准将面向通用对象的变电站事件（GOOSE）报文直接映射到数据链路层，能有效减少传输延迟。文中对GOOSE报文在变电站智能电子设备（IED）中的处理延迟进行了研究。分析了前后台方式的嵌入式系统在变电站IED中处理实时报文方面的不足，提出在IED中采用具有强实时内核的操作系统，并针对IED中实时报文和非实时报文混合处理环境需求，在RTAI实时操作系统上设计了保障GOOSE报文处理实时性的方案。实验验证了该方案的有效性和实用性。该研究结果对于使用IEC 61850的变电站IED过程总线通信设计具有参考意义。     

数字化变电站中双网控制策略

IEC制定的变电站内通信网络和系统标准体系（IEC 61850）中没有涉及双网通信、装置与操 作箱控制通信等内容,显然其不能满足大部分数字化变电站可靠运行的要求。通用面向对象的变 电站事件（GOOSE）直接基于ISO/IEC 8802-3以太网协议进行数据传输,有着较高的传输效率,是 数字化变电站的主要特点之一。文中描述的数字化变电站中双网控制策略是基于GOOSE协议的 双网控制策略,该策略不但使系统控制具有快速性和冗余性,也提高了系统控制的安全性和可靠 性,满足了数字化变电站各种控制应用需求。数字化变电站中双网控制策略可作为IEC 61850的 补充。     

基于IEC 61850的数字化故障录波器的研制

数字化故障录波器采用基于PowerPC8270的硬件平台和基于嵌入式Linux操作系统的软件平台。装置接收合并单元发送的遵循IEC 61850-9-1标准采样值数据报文和保护控制单元发送的遵循IEC 61850-8-1标准的面向通用对象的变电站事件（GOOSE）报文，按照同步采样的合并策略，实现在全球定位系统（GPS）同步和失步状态下开关量数据和采样值数据的同步，提取正确的GPS时间，最终形成故障录波文件，较好地满足了数字化变电站中对故障录波器的新要求。     

基于IEC 61850 GOOSE技术的继电保护工程应用

从继电保护可靠性、速动性以及运行检修、工程设计的要求出发,通过分析IEC 61850提供的通用面向对象的变电站事件（GOOSE）快速报文机制和保护装置硬件结构、软件逻辑,对GOOSE技术应用于继电保护的关键技术,如保护装置GOOSE网口设置、智能操作箱的应用、GOOSE报文的数据处理、运行检修“隔离”措施以及GOOSE配置和工程设计等进行了研究分析,给出了数字化变电站GOOSE技术继电保护应用方案,并已在实际工程中得到了应用。     

基于VxWorks系统的GOOSE实现与可靠性分析

面向通用对象的变电站事件（GOOSE）模型是IEC 61850对数字化变电站的重要贡献,其出发点是变电站自动化功能的分布式实现。通过分析VxWorks操作系统内核的特点,提出了基于VxWorks的IEC 61850 GOOSE发布的实现方案。GOOSE发布任务基于VxWorks事件组,采用事件驱动方式处理GOOSE初始发送、变化发送、快速重发和周期重发。给出了各GOOSE发送控制块共享的高精度定时器的使能和关闭方法。分析了VxWorks网络重发的实现原理,提出了新添加GOOSE协议的重发送实现方式。     

新型变电站综合测控装置优化设计

结合特高压电网、数字化变电站的建设,研究变电站自动化系统测控技术,并对测控装置进行优化设计。在变电站信息采集源头进行信息的整合和标准化,使其得到更有效的利用。结合IEC 61850标准中通用面向对象的变电站事件（GOOSE）机制和其他一些新技术,实现过程层网络化信息传输,推动变电站的数字化建设。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients

Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L^?1 PO₄. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

簸箕李引黄灌区水沙分布及优化调度的经验

灌区利用水沙观测所取得的资料和试验数据，运用水沙运动力学理论，总结分析和揭示了灌区水沙分布的规律和特点。在此基础上，结合灌区的实际运行情况，围绕减少骨干渠道的淤积进行探讨、研究，进而，优化水沙调度方案。该方案实施后，骨干渠道减旅伴效果明显，取得了成功的经验。     

小湾水库大坝防渗面板及其裂缝的加固处理

小湾水库大坝防渗面板整体抗渗性能差,且存在多条裂缝,通过对面板钢丝网喷涂丙乳砂浆加固处理及其裂缝修补,大坝渗漏量明显减少,且左岸上灌浆廊道内及大坝下游坝面92～93 m高程下廊道入口处原有小股射流全部消失.     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).