The development of coil short circuits when transformer windings become contaminated with metal-containing colloidal particles

The radiational-thermal development of coil short circuits due to the action of partial discharges of the first kind when the windings of transformers, autotransformers and shunting reactors become contaminated with metal-containing colloidal particles, formed in the transformer oil as a result of the interaction of the oil with the constructional materials (the copper of the windings, the iron of the tank, the core etc.) is considered. Acriterion of dangerous contamination of the coil insulation of the windings by metal-containing colloidal particles is proposed, namely, 3% of the mass content of copper and iron in it, which, if exceeded, may serve as a basis for recognizing the state of transformers, autotransformers and shunting reactors at a voltage of 110 kV and above the limit. It is shown that filters for continuously cleaning the oil play a considerable role in prolonging the life of transformer equipment.     

Interrelation of surface tension,optical turbidity,and color of operational transformer oils

Measurements of the acidity, optical turbidity, surface tension, and color of transformer oil from 54 power transformers, autotransformers, and shunt reactors are reported. Changes in surface tension, optical turbidity, and color are found to obey adequate linear correlations, while the acidity has no correlation with any of these properties. Numerical criteria for the maximum permissible state (quality) of the oil with respect to optical turbidity and color are obtained. Recommendations to operating staff are provided for cases in which the criteria for optical turbidity and color are exceeded.     

TransFix变压器油在线监测系统在小浪底水电厂的应用

简要介绍了小浪底水电厂开展变压器油色谱在线监测的意义,以及采用动态顶空平衡法进行油气分离、采用光声光谱技术进行气体检测的TransFix变压器油中溶解气体及微水在线监测系统的原理及应用情况,给出了相关的试验数据.     

津河水体藻污染监测识别及无机混凝剂除藻效能研究

针对津河水体开展长达18个月的定点采样监测分析,对造成藻华现象的优势藻种进行了显微识别。结果表明,近两年津河水体总体为富营养化状态,其中每年7、8月份藻华暴发,呈现重富营养化特征,经观察鉴别属于微囊藻型蓝藻污染。以Chl-a、浊度及UV254为主要水质参数,探索投加无机混凝剂用于藻污染控制的可行性,并对4种混凝剂的藻污染控制效果进行了比较。结果表明,投加无机混凝剂控制津河藻污染效果显著(聚合氯化铝对Chl-a和浊度去除率分别高达89%和92%),相同实验环境下混凝净化效能依次为:PAC(聚合氯化铝)PFS(聚合硫酸铁)FC(三氯化铁)AS(硫酸铝)。     

Chemical stress induced by copper: examination of a biofilm system.

Biofilm systems have been widely used in wastewater treatment plants. However, little information is available on the impact of toxic chemicals on the performance of fixed film systems. This study was aimed at evaluating the impact of copper on a biofilm system by examining a variety of parameters, including reactor pH, DO, substrate concentrations, secretion of extracellular polymeric substances (EPS), and copper removal and accumulation. The microbial communities in the biofilms were also examined using automated ribosomal intergenic spacer analysis (ARISA). Four rotating drum biofilm reactors were used to produce biofilms. One reactor was used to produce biofilms under copper free conditions; while the others were used to produce biofilms grown under three different copper contamination levels, namely 100 ppb, 200 ppb, and 500 ppb, for a prolonged period. The following results were obtained: (1) biofilm reactor performance was not significantly impacted as demonstrated by the pH, DO, substrate removal, and total solids in the effluent; (2) however, copper contamination inhibited EPS production in the biofilms; (3) copper removal efficiencies of 25-31% were obtained for the three copper contamination levels studied; (4) fixed films functionalized as a reservoir to accumulate more copper over time; and (5) copper contamination selected for specific species that were able to tolerate this stress and that may contribute to its remediation.     

Trace Element Concentrations in Near-Surface Waters of the Great Lakes and Methods of Collection,Storage, and Analysis

From 1980 through 1985, waters of the Great Lakes were sequentially sampled for dissolved, paniculate, and total trace elements. Major sampling occurred in 1980 for Lake Huron, in 1981 for Lakes Erie and Michigan, in 1983 for Lake Superior, and in 1985 for Lake Ontario. Great care was taken during collection, storage, and analysis to prevent sample contamination and to document any contamination occurring. Trace elements measured by atomic absorption techniques were silver, aluminum, arsenic, boron, barium, beryllium, bismuth, cadmium, cobalt, chromium, copper, iron, mercury, lithium, manganese, molybdenum, nickel, lead, antimony, selenium, tin, strontium, vanadium, and zinc. All results were field and laboratory blank corrected. Excluding aluminum, barium, iron, and strontium, concentrations of trace elements in most of the Great Lakes were a few ppb or less, with many elements being below one ppb. Element concentrations were highest in Lakes Erie and Michigan and lowest in Lakes Huron and Superior. All five Great Lakes had more than 50% of their total iron, aluminum, and manganese associated with paniculate matter.     

Assessment of heavy metal contamination in coastal lake sediments associated with urbanization: Southern Kerala,India

The study of the spatiotemporal variation of heavy metals in lake sediments is of great importance because heavy metals can result in toxic effects on aquatic biota through bioaccumulation. This study was undertaken to evaluate the degree of heavy metal contamination in the lacustrine sediments and the corresponding environmental deterioration in a tropical, urban, coastal lake (Akkulam–Veli), located in Kerala, India. The spatiotemporal variations of the cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn) concentrations in the lake sediments, as well as various indices of anthropogenic contamination, including Contamination Factor (CF), Pollution Load Index and Geoaccumulation Index (Igeo), were used to assess the degree of contamination. This study indicated contamination of the lake sediments with Cu, Pb and Zn. Urban domestic sewage and land run‐off are the major drivers of the heavy metal loads to the lake. During the pre‐monsoon, sediment contamination occurs in the upstream portion of Akkulam Lake because of a high clay content in the sediments. During the monsoon period, Akkulam Lake and the upstream portion of Veli Lake exhibit sediment contamination owing to high silt content. Domestic sewage is the main source of copper and zinc to the lake. Sewage bypass into the drains in the lake basin is largely responsible for the copper and zinc sediment contamination. High traffic levels and wastewater discharges from service stations/workshops are the main cause of the Pb loads entering the lake. Rubber particles of vehicle tires contain zinc and copper pigments that can accumulate on the surface of busy streets, entering the drains during rainfall events. Based on these study results, the accumulation of copper, zinc and lead in lake sediment can be controlled to a great extent by restricting the above‐noted activities. As the sediment content of lead, zinc and copper is confined to the clay fraction during the non‐rainy season and to the silt fraction during other seasons, lake restoration work should largely incorporate treating the clay and silt fractions, respectively, during both the non‐rainy season and rainy season.     

配水管网中水质变化规律及主要影响因素分析

安全输配是饮用水水质保障的关键。在对中国南方 S 市配水管网水质大量调查的基础上,分析了余氯、浊度、铁、三卤甲烷、卤乙酸、AOC 等主要水质指标在管网中的变化规律,发现余氯沿管线逐渐降低,浊度和铁基本沿管线逐渐增加,其主要影响因素有管道属性、温度及水力条件等;三卤甲烷在管网中表现出增加的趋势,而卤乙酸则在管网中表现出降低的趋势,其主要影响因素有余氯浓度、水质条件、温度条件及水力条件等;供水系统中 AOC 以 AOC-P17为主要组分,沿供水系统有逐渐增加的趋势,其浓度、组成以及在管网中的变化规律呈现明显的季节性。     

水源切换期用户水质跟踪监测及铁稳定性分析

针对北方某市水源切换对典型地区实际给水管网铁稳定性的影响开展试验研究。选取2个小区用户各1家,对其管网出水水质进行连续10个月的跟踪监测。结果表明,在本次水源切换过程中,管网水的SO42-有较大幅度变化,平均从25 mg/L增加到75 mg/L,之后又降至45 mg/L;造成管网出水的浊度和总铁有所增加,部分监测值超出饮用水标准,最高达到6 NTU和1.2 mg/L。不同小区管道铁稳定性存在明显差异,管网水中铁含量和浊度具有一定的线性关系。分析水源切换前后不同时期管网出水水质的变化,得出SO42-与管垢铁释放有较好的相关性。     

Assessing the health implications of turbidity and suspended particles in protected catchments.

The supply of unfiltered disinfected drinking water from Melbourne's fully protected catchments means that the water-quality managers must ensure that the source water poses no public health risk. High turbidity is currently used as a surrogate of pathogens, and harvesting of water is based on its measurement. The work presented here summarises suspended particle and associated pathogen, microbial indicator and faecal biomarker concentrations collected to (a) quantify turbidity in an Australian water supply system and (b) assess the possibility of increasing water harvesting from selected tributaries. Pathogens and microbial indicators were present in low numbers in these source waters; increased turbidity during storm events was not associated with an increase in pathogen concentration. The results confirmed that protected catchments, along with good management, were effective barriers to pathogen contamination. Aesthetic issues still need to be addressed, but no measurable increase in microbiological risk was associated with storm-generated particles.     

Predicting suspended sediment concentration from nephelometric turbidity in organic‐rich waters

Nephelometric turbidity is an optical index for the side scattering of light caused by fine particles suspended in water. When a mixed composition of suspended inorganic and organic materials, including dissolved organic material, is present, turbidity measurements can be affected by the different optical properties of the organic and inorganic materials present, and different turbidimeters are more or less sensitive to these influences. Two different methods of nephelometric turbidity measurement were assessed (using instruments confirming to two different turbidity standard methods: EPA 180.1 and ISO 7027). We investigated the influence of particulate organic matter and coloured dissolved organic matter on relationships between turbidity and suspended sediment concentration for rivers in diverse Otago catchments, in the South Island of New Zealand. The presence of organic matter and dissolved colour affected turbidity measurement owing to light absorption; however, turbidity measurement following the ISO 7027 standard, which specifies near infrared radiation at wavelengths where organic absorption is very weak, was less affected by organics. As a result, rating equations between suspended sediment and turbidity may be significantly different with ISO 7027 compared with EPA 180.1 methods.     

一起主变压器压力释放阀喷油原因分析及处理

介绍了水布垭电厂压力释放阀动作的原因、开关断开后的处理经过、随油温变化变压器的体积计算及油位计校验方法,提出了主变压器出现非电气故障时的防范措施。     

The application of surface engineered silica for the treatment of sugar containing wastewater

The removal of sucrose and fructose from water at various high concentrations by surface engineered silica (SES) was studied using dissolved sugar in pure water. The results indicate that sugar at concentrations of up to 800 g/L can be removed by SES at a relatively high dose of 250 to 300 g/L. Based on these results, process water from a soft drink filling station which was contaminated by sugar, flavour components, Escherichia coli, Pseudomonas aeruginosa bacteria and Candida pelliculosa yeast were treated to study the performance of SES using actual process water samples by analysing turbidity, biological oxygen demand (BOD), UV absorption, and various other standard parameters, and microbial tests. The study shows that at a dose of 100 g/L of SES bacterial contamination as well as turbidity, BOD and UV absorption can be significantly reduced. However, the study found the yeast species Candida pelliculosa could not be removed from the water samples.     

低温低浊水混凝沉淀处理研究

研究快速搅拌强度(GR)、快速搅拌时间、缓速搅拌时间以及pH等因素对低温低浊水混 凝沉淀效果的影响。研究结果表明,当混凝剂投加量一定时,选择合适的混凝条件,沉后水浊度、沉 后水中混凝剂残余量及过滤阻抗系数STI将有较大改善。并且伴随快速搅拌强度的增大,与沉后水 浊度相比,混凝剂残余量及过滤阻抗系数改善更加显著。     

三峡上游洪水预报实时校正方法应用比较

实时校正方法是提高洪水预报精度的有效途径.将误差序列实时校正、反馈模拟实时校正、卡尔曼滤波实时校正等方法,应用到三峡上游的洪水预报中,并针对各种方法阐述了其优缺点.误差序列实时校正简单实用,但是校正预见期较短;反馈模拟实时校正基于实测流量进行校正,但是要求实测点距较多;卡尔曼滤波校正准确度较高,不过原理复杂,较难确定滤波参数.最后对几种校正方法进行了分析比较.     

基于PXI的变压器在线监测系统

针对变压器主要的潜在故障特性，综合超高频局部放电监测、超声波局部放电定位、油色谱分析、套管介质损耗监测和铁心接地电流监测等在线监测手段，能及时、有效地对变压器的健康状态做出分析和判断。文中采用面向仪器系统的PCI扩展（PXI）总线仪器在LabVIEW开发平台上建立了一套变压器在线监测与分析系统，详细介绍了系统硬件平台的选择、系统框架和软件功能模块。该系统具有硬件可靠性、软件可移植性和可扩充性等特点。     

Using CANARY event detection software for water quality analysis in the Milwaukee River

Urban water sources are susceptible to various contamination events as a result of natural, accidental, and human-induced occurrences. An early warning monitoring system provides timely information on changes in urban water quality. In this study, an analysis was made with CANARY event detection software (EDS) to monitor water quality parameters in river water and to identify the onset of anomalous water quality periods. Water quality signals including pH, conductivity, and turbidity from the Milwaukee River over specified periods during the summer season of 2018–2020 were employed as inputs to event detection algorithms in CANARY. The data analysis results show that CANARY can be useful as an early warning system for monitoring contamination in urban water sources and help to identify abnormal conditions quickly. The sensibility of the model relies on optimizing the configuration parameters, which involves selecting the ideal set of parameters for the event detection algorithm and adjusting the BED parameters to increase or decrease the probability of generating an alarm. The number of events reported between the Linear Prediction Correction Filter (LPCF) and Multivariate Nearest Neighbor (MVNN) algorithms varied as a result of different residual calculation mechanisms. Climate factors that contributed to the abnormal water quality events in the river were examined. The analysis of rainfall on water quality was carried out using a statistical method by determining whether there is a significant difference (p-value) between the seasonal mean water quality data and the mean value of water parameters during the sampling duration. Regression analysis was also performed to estimate the best model that describes the relationship between each of the water quality parameters and temperature.     

Enhancing the removal of arsenic, boron and heavy metals in subsurface flow constructed wetlands using different supporting media

The presence of arsenic and heavy metals in drinking water sources poses a serious health risk due to chronic toxicological effects. Constructed wetlands have the potential to remove arsenic and heavy metals, but little is known about pollutant removal efficiency and reliability of wetlands for this task. This lab-scale study investigated the use of vertical subsurface flow constructed wetlands for removing arsenic, boron, copper, zinc, iron and manganese from synthetic wastewater. Gravel, limestone, zeolite and cocopeat were employed as wetland media. Conventional gravel media only showed limited capability in removing arsenic, iron, copper and zinc; and it showed virtually no capability in removing manganese and boron. In contrast, alternative wetland media: cocopeat, zeolite and limestone, demonstrated significant efficiencies--in terms of percentage removal and mass rate per m3 of wetland volume--for removing arsenic, iron, manganese, copper and zinc; their ability to remove boron, in terms of mass removal rate, was also higher than that of the gravel media. The overall results demonstrated the potential of using vertical flow wetlands to remove arsenic and metals from contaminated water, having cocopeat, zeolite or limestone as supporting media.     

万家寨水电站变压器过热分析与处理

在万家寨水电站投运不久，先后发现三台主变压器绝缘油色谱分析总烃超标，存在过热缺陷。因为万家寨电厂是调峰厂，负荷极不稳定，给分析带来一定的难度。通过长期色谱分析和电气试验分析工作，查明原因，并最终进行了大修处理。经过近一年的跟踪分析，证明已经消除了该过热缺陷。     

给水管网中管材对水质变化的影响研究

研究了给水管网中镀锌钢管、铝塑管等常用管材中水质变化的规律,得出了三种管材中游离氯和化合氯的衰减规律,分析了金属离子溶出的影响因素.发现三种管材中旧镀锌钢管的余氯衰减最快,新镀锌钢管比铝塑复合管余氯衰减要快,旧镀锌钢管中余氯衰减呈现一级动力学特征,新镀锌钢管和塑料管余氯衰减呈现零级动力学特征.随着管网水停留时间的增加,锌、铁等金属离子浓度增加,溶出铁的含量与浊度、色度呈现很好的线性相关关系.