Table of Content

05 November 2018, Volume 51 Issue 11

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Analysis of Performance Deterioration of Steam Turbine Units Based on EMD-CFA Method

WANG Huijie, DONG Xuehui, YANG Jie, LUO Tianci, ZAN Yongchao

2018, 51(11):  1-8.  DOI: 10.11930/j.issn.1004-9649.201805063

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In this paper, regarding the load variation under different operation conditions, the characteristic flow area of the steam turbine extraction sections is taken as the benchmark value to evaluate the deterioration of the steam turbine performance, which is calculated in terms of the specific volume and the temperature respectively. Based on the historical data of a power plant, the characteristic flow area is calculated and the error analysis is then carried out. It is discovered that the results calculated by the specific volume is more accurate than that by the temperature. To verify the correctness of the results, the C-language based dynamic web page is created for real-time monitoring by employing the characteristic flow area of the specific volume as the benchmark. Then by using the empirical mode decomposition (EMD) method, the deterioration trend is analyzed on the big data of the long-term operation such that the micro trend of each extraction section is obtained. Moreover, once the degradation reaches a certain level, an early warning will be issued for the failure alert.

The Adaptive Fuzzy Control System for Main Steam Temperature Based on Smith Predictor

PING Yuhuan, GUAN ZHimin, LI Zongyao

2018, 51(11):  9-14.  DOI: 10.11930/j.issn.1004-9649.201711243

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Due to the large time-delay, high inertia and model uncertainty of the main-stream temperature object in fossil-fired power station, it is difficult to achieve satisfactory results with conventional cascade PID control. In this paper, in combination with the fuzzy theory and Smith prediction technology, a new fuzzy adaptive control system for main steam temperature based on multi-model and Smith predictor is proposed, in which by virtue of Smith predictor the inner loop generalized controlled object is estimated and then a fuzzy adaptive controller is applied to control the generalized controlled object. This control system is simple to be implemented with satisfactory self-adaptability to various operating conditions. Furthermore, from the simulation results under five different conditions this control system exhibits strong robustness and anti-disturbance capabilities. In addition, the control method can be applied with easiness in the existing distributed control system and fieldbus control system without extra hardware investment, which has higher value of engineering applications.

Chemical Cleaning for Inner Cooling System in Generator with High Content Copper Deposition

WU Junjie, LIU Kai, ZHOU Zhou, ZHA Fanglin, FENG Bing, WAN Tao, XU Song, GONG Shangkun

2018, 51(11):  15-19,184.  DOI: 10.11930/j.issn.1004-9649.201711006

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Insulation deterioration and cooling capacity decrease due to corrosion and deposition of corrosion products in inner cooling water system are potential threats to generator operation. At a power plant of Hunan Province, abnormal temperature and blockage are observed in the generator inner cooling water system with high content copper in the corrosion products. To address the potential issues, chemical cleaning is carried out for the first time by using amino sulfonic acid based composite acid with the addition of hydrogen peroxide in combination with multi-step rinse process to eliminate copper oxides and copper. The results indicate that, by taking advantage of this technology the inner corrosion products are effectively cleared with very few damages to the stator bar. The before and after comparison shows that the temperature of stator winding during operation was reduced up to 9.9℃. The maximum temperature difference between stator coil bars is reduced by 10℃, while the maximum temperature difference between the water outlets from stator coil bars dropped by 11℃, respectively. In this way the secure and economical operation of generator can be ensured.

Analysis of the Fracture Morphology of FB2 under Low-cycle Fatigue

YANG Baixun, DING Lingling, TIAN Xiao, XU Hui, LI Yimin

2018, 51(11):  20-25.  DOI: 10.11930/j.issn.1004-9649.201801009

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Low-cycle fatigue properties of FB2 steel under room temperature and 620℃ are analyzed by axialload constant-amplitude method. The fracture morphology and microstructure of the low-cycle fatigue specimen are observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). Results illustrate that the FB2 is cyclic softening material. Its cyclic life under high temperature is far shorter than that under room temperature. The relationship between the cyclic strain and its life satisfies the Manson-Coffin model. SEM analysis shows that the fatigue cracks usually initiate from the surface defects or BN inclusions. The fatigue striations as well as the intact BN inclusions can be clearly distinguished. TEM analysis shows that the cyclic softening of FB2 steel is the consequence of the reduced density of dislocation, the transform of martensite laths together with the form and coarsening of sub-grain.

Research on Water Distribution Device with Double Layer Multiple-Perforated Plates in High-flowrate Mixed Bed Polisher

TIAN Wenhua, ZHU Xiaoliang, LEI Junru, XU Guanghua, LIU Yiran

2018, 51(11):  26-31.  DOI: 10.11930/j.issn.1004-9649.201712004

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The water distribution device with vaulted baffle-perforated plates and strainers always introduces bias flow in high-flowrate mixed bed (HFMB) polisher. This paper analyzes the issue and figures out the root cause as the deform and damage of the perforated plates. Then the design scheme of water distribution device with vaulted baffle-double perforated plates is proposed, in which the design parameters are optimized through computer simulation technology of fluid mechanics. The new scheme has been applied in technical renovation engineering project of water distribution device in HFMB polisher of a 680 MW ultra-supercritical unit. The result after three months of operation shows that by applying this water distribution device with double perforated plates there were very little differential pressure during operation while the water distribution is uniform with stable water quality in HFMB polisher. The volume of periodic water production has increased from 66,000 m³ to 109,000 m³, which is of great significance for water saving and emission reduction.

Study on the Application of Roots-Water Ring Pump in Large Direct Air-Cooling Power Plant ACC System

AN Yajun, ZHANG Zhiyong, CHEN Ruijun, SUN Jian, ZHAO Ziyuan, SHEN Mengling

2018, 51(11):  32-37.  DOI: 10.11930/j.issn.1004-9649.201806040

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In order to solve the problem of cavitation of the electric water ring vacuum pump used in thermal power plants, through the test on the vacuum system output of a 600-MW direct air-cooling unit, this paper proposes that there exists the maximum suction output in the water ring pump operation, and analyzes the reasons why the output may decrease. Then the cavitation of the water ring pump is also investigated associated with the issue of water ring pump rotor cracks. Based on the study, a front dewatering roots-water ring pump group system is designed. By taking the test data and the pump group selection theory into account, an alternative scheme for the existing pump group is put forward, which can effectively tackle the problem and remarkably save the energy.

Power Loss Prediction of Large Blackouts in Power Grid Based on ARMA-GABP Combined Model

YU Qun, ZHANG Zheng, QU Yuqing, HE Qing

2018, 51(11):  38-44.  DOI: 10.11930/j.issn.1004-9649.201801046

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Power loss is an important index to measure the risk of blackouts, and it is very important to accurately predict it for the safe operation of power grid. In this paper, the power loss of large blackouts in Northeast Power Grid and Northwest Power Grid from 1981 to 2016 are selected as experimental data. In order to eliminate the influence of power grid development on data analysis, the relative value method is used to process the power loss of grid blackouts. According to the characteristics of the experimental data, the data structure of the relative value of power loss is decomposed into linear and non-linear residuals. A combined ARMA and GABP neural network model is established to comprehensively analyze and predict the large-scale blackout accidents in Northeast China Power Grid. The prediction results of the proposed model are compared with those of the single model and the ARMA-BP model. The results show that the proposed model has higher prediction accuracy and better prediction effect. In order to further verify the validity of the forecasting model, the data of large blackouts in Northwest Power Grid are substituted into the forecasting model. The experimental results indicate that the forecasting model has a good forecasting effect in terms of power loss caused by large blackouts.

The Application of JSInSAR Technology in Substation and Power Tower Deformation Monitoring

XIAO Xingquan, ZHANG Jinbao, JIAO Yifei, Chen Zhongguo, XIONG Xiaoman, HUANG Shijing, JIAO Min

2018, 51(11):  45-52.  DOI: 10.11930/j.issn.1004-9649.201803007

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The deformation of substations and power towers could threaten the secure transmission of electric power. Due to the sparsity of distributed monitoring points, the traditional PSI technology is incapable of achieving high-precision measurement in practice. Alternatively, this paper adopted the JSInSAR technology to obtain the millimeter-scale deformation monitoring results of two 500 kV substations and surrounding power towers in Jianshan and Jiujiang areas of Chengdu, and analyzed their time-series deformation trends from both vertical and horizontal dimensions, based on 18 TerraSAR-X Strimap high-resolution image data. Simulation results showed that the spatial density of deformation monitoring points with JSInSAR technology is 4 times larger than those with the traditional PSI technology; two substations are in safe operating stations, with a relatively small vertical and horizontal cumulative deformation difference, which confirms the superiority of JSInSAR technology on increasing the spatial density of deformation monitoring points and obtaining more abundant deformation details. Compared with traditional ground-based monitoring methods, the space density of the deformation monitoring points as well as its accuracy with JSInSAR technology are higher, suggesting broad application prospects in power infrastructure monitoring of JSInSAR technology.

Coupling Mechanism and Control Measures of Dynamic Frequency and Voltage in Isolated Power Grid

LYU Sizhuo, ZHENG Chao, PENG Li, SONG Xinfu, GAO Kai, LYU Pan, TANG Junci

2018, 51(11):  53-60.  DOI: 10.11930/j.issn.1004-9649.201706147

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The regional power grid will change to isolated power grid operation after disconnected with main network. Considering the low inertia of isolated power grid, the interaction between frequency and voltage is significant under the impulse of large capacity unbalanced power. This paper firstly reveals the coupling mechanism of frequency and voltage in isolated power grid. And then, through constructing the equivalent model of single machine and singe load, the paper analyzes the influence of transmission power, load frequency factor and compensation degree on the dynamic process of frequency and voltage. Finally, based on the actual operation of the Tibet power grid, some stability control measures are put forward to address the over-frequency and overvoltage of isolated power grid, and their effectiveness is verified through simulation. The research results can provide a technical basis for the stable operation of the Tibet power grid after the central-Tibet interconnection project is put into operation.

Type Selection and Layout Plan of 1 000 kV Substation Electrical Equipment in Cold and High Altitude Areas

WEN Weibing, KANG Peng, LIU Fei, HU Junhui, GUAN Lan, ZHANG Fei, YING Jie

2018, 51(11):  61-66.  DOI: 10.11930/j.issn.1004-9649.201711001

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High altitude and low temperature will have a significant impact on type selection and layout of 1 000 kV substation equipment. At present, there are no design and construction experiences as well as related technical reserves for UHV substations under such ambient conditions. Based on an investigation of the current equipment manufacturing level and the operation conditions of existing projects in such environment, and after a comparison of different technical schemes, the paper proposes the external insulation correction method for 1 000 kV equipment, the type of 1 000 kV equipment bushing and the installing principle of heating belt for GIS under the ambient temperature of –45℃ and below the altitude of 3 500 m. The recommended equipment layout scheme is presented through technical and economic comparison. The research results can provide a reference for construction of the follow-up 1 000 kV substations.

The Impact of Outside Electricity on the Ancillary Service of Power Grid with High-Penetration Received Electricity

WANG Weiyuan, ZHAO Nan, ZHANG Jiannan, ZHU Huan, WANG Beibei, DOU Fei, NIU Wenjuan

2018, 51(11):  67-73.  DOI: 10.11930/j.issn.1004-9649.201707090

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With a large number of UHV projects being put into operation in recent years, the proportion of received electricity in the receiving-end grid has increased substantially. To improve the stability and reliability of the power grid, the ancillary service is highly important to the receiving-end grid with high-penetration received electricity. Focusing on the ancillary service, this paper discusses the influence of the characteristics of outside electricity on the peak-shaving and standby capacity demand. Based on the optimized peak-shaving and standby demand, the outside electricity is equivalent to three-segment output power, and a multi-generation combined model is used to simulate the impacts of the outside electricity on local generation sources. The simulation results show that the outside thermal power has a relatively small impacts on peak-shaving and standby demand, and the hydropower has the biggest impacts on the standby demand in valley load time because of its full-capacity generation during flood season,while the outside wind power has the biggest impacts on peak-shaving duo to its reversed peak-shaving features and very high impacts on the standby demand in valley load time due to its uncertainty and high output in valley load period.

Design and Experiment of Intelligent Switch Controller Based on LPC2103

ZHANG Fu, WANG Yafei, LIU Hongmei, MA Tianle, WANG Jun

2018, 51(11):  74-80.  DOI: 10.11930/j.issn.1004-9649.201801045

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In this paper, an intelligent controller system is designed to overcome low intelligence degree and the lack of data acquisition accuracy for the current interface switch controller. Through the modular design method, the ARM microprocessor is employed as the core part for detecting distribution line voltage, current and switch status information in the intelligent controller system. Then, the test data can be uploaded to the monitoring center through wireless module. The operating state of distribution line and switching status can be monitored in real time. The voltage and the current are measured using the intelligent controller system. The correlation coefficient of the measured and the calculated of current is 0.9961, and the correlation coefficient of the measured and the calculated voltage is 0.9968. The results show that the presented controller system can satisfy the requirements of error control (±0.5%). This paper provides a basis for research on intelligent controller in power system distribution circuit.

Coordination of Wind Power Transmitted Through UHV Transmission Corridors Bundled with Thermal Power and Jiangsu Power Grid

XU Yiqing, GE Yi, LV Xiang, HUANG Junhui, XIE Zhenjian

2018, 51(11):  81-87.  DOI: 10.11930/j.issn.1004-9649.201612025

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The paper proposes a modelling method of the bundled wind-thermal ultra high voltage (UHV) transmission system. The mathmatical model of the power system is established based on the dynamic power output characteristics at the sending end of the UHV transmission line and power dispaching rules. Then, a paramter tunning method during peak and off-peak month of load at receiving end is also presented based on load characteristics. The proposed modelling method of the bundled wind-thermal UHV transmission system not only provides a valid model in power system simulations, but also can be used to reduce power loss at the receiving end and operational cost of the power system. Simulation results show that the operational efficiency of the power system can be improved, and the wind power curtailment ratio can also be controled properly, when the proposed modelling method is applied in Jiangsu Power Grid.

Identification of Main Harmonic Current Sources Based on the directions of Reactive Power

XU Cheng, ZHAO Hong, WANG Jincao, YUAN Lin

2018, 51(11):  88-95.  DOI: 10.11930/j.issn.1004-9649.201702056

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Currently it is difficult to pinpoint the origin of power loss in power system components as caused by harmonic current. To solve this problem, the paper proposes a method to locate harmonic current sources at the Point of Common Coupling (PCC) based on the directions of reactive power. Normally the power loss caused by harmonic current flowing through power system components can be attributed to be from either power system side or user side. The attribution is indicated by harmonic current index. The paper proposes a method to identify harmonic current sources (either power system side or user side) based on the phase difference between harmonic voltage and current. The proposed method is based on the harmonic impedance characteristics of the power system, measured harmonic voltage and current at PCC, circuit theory and inequality constraint. Finally, the approach is demonstrated and validated by the real data obtained in field tests. Experimental results suggest that the proposed approach is not only convenient to use but also has great engineering value.

Influence of the Combination-Type Grounding Scheme on Voltage-Injected Stator Ground Fault Protection

ZHANG Qixue, WANG Xiangheng, CHEN Jiasheng, XU Tianle, LI Huazhong, WANG Guang, CHEN Jun

2018, 51(11):  96-103.  DOI: 10.11930/j.issn.1004-9649.201805084

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By drawing upon the advantages of the resonant grounding method, a combination-type grounding scheme is adopted for large-sized generator to reduce the ground fault current, in which the inductor is installed in parallel with the load resistor on the LV-side of the neutral grounding transformer (NGT). In the paper, a numerical simulation model is established by using Matlab Simulink. The quasi-distributed capacitance model is used to simulate the stator ground fault protection, and the algorithm used for the protection devices is adopted to calculate the voltage-injected stator ground fault protection. A conventional high-resistance grounding scheme and three combination-type grounding schemes are designed, and simulations are carried out for the large-sized generator of Baihetan hydropower station in China. By comparing the simulation results, a study is made on the influence of the combination-type grounding scheme on the voltage-injected grounding protection. The results show that adding parallel inductor will worsen the calculation results of the ground fault resistance; the parallel inductor installed on the high voltage side of the NGT is most favorable to the voltage-injected stator ground fault protection, but the equipment cost will be increased; within the limited amount of compensation current by the parallel inductor, the greater the degree of detuning is, the better the measurement of the ground fault resistance is.

Deepening Construction of Jiangsu Source-Network-Load Millisecond-level Precise Load Control System Suitable for UHV Power Grid Operation

QIAN Junxia, LUO Jianyu, JIANG Yefeng, LUO Kaiming, JIANG Tairong, Li Yaping, LIU Lin, ZHANG Huacheng, SHI Huijuan

2018, 51(11):  104-109.  DOI: 10.11930/j.issn.1004-9649.201801082

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Based on an analysis of the characteristics of Eastern China UHV grid and the necessity of the frequency control of the Eastern China power grid in the end of 2019, the paper calculates the capacity demand for load-shedding of Jiangsu power grid. According to the construction and operation situation of China's first set of source-network-load friendly interactive system, which has been put into operation in Jiangsu Power Grid, a deepening construction plan is proposed. Through inclusion of the load of power plant's auxiliary generator units for the precise control of source-network-load which doesn't affect the power output of the generator units, a hierarchical partition communication structure is established, which is adaptable to the large-scale, multi-type millisecond response. After a comparison of the technical schemes, the system's overall structure is optimized into four levels, including the control center, main control station, control substation and control terminal. The deepening construction plan is of great significance for the state grid to further promote and strengthen the construction of millisecond-level precise load control system of source-network-load.

Simulation Analysis and Research on Electromagnetic Field of Ultra-Special High Pressure Oil-immersed Reactor

YU Longyang, LIU Ye, YU Shimiao, LU Yinpu

2018, 51(11):  110-116.  DOI: 10.11930/j.issn.1004-9649.201711097

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The 1 100 kV UHV shunt reactor has been greatly developed to meet the development of electric industry in China. In this paper, aiming at the simulation analysis of the electromagnetic field and force of the UHV shunt reactor, the finite element 3D model of the oil-immersed reactor is established firstly. Then, the magnetic flux leakage phenomena and magnetic circuit of the reactor core column are analyzed. Finally, the magnetic cloud and electromagnetic force cloud images of each component are calculated. Comparing with the experimental data under actual working conditions, the results show that the error of the simulation is small, which shows the validity of the simulation results of the reactor magnetic field and electromagnetic force. The results provide theoretical support for solving the existing problems of vibration and overheating of the UHV shunt reactor.

Capacity Configuration Strategy for Super Capacitor-Flywheel-Battery Hybrid Energy Storage System

LI Xiang, ZHANG Jiancheng, WANG Ning

2018, 51(11):  117-124.  DOI: 10.11930/j.issn.1004-9649.201802037

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Through the utilization of the hybrid energy storage system, the annual comprehensive cost of energy storage system can be reduced and the economic benefit of photovoltaic power generation system can also be improved. The empirical mode decomposition method is used to decompose the power imbalance between photovoltaic generation and load into high frequency component, intermediate frequency component and low frequency component, which is taken as the reference power of super capacitor, flywheel and battery respectively. In addition, this paper established capacity allocation optimization model with the annual cost as objective function, charging/discharging power and state of charge as the constraints. Genetic algorithm was then deployed to minimize the objective function. Finally the case study result verified the effectiveness of the configuration strategy.

Contribution Evaluating Model for the New Energy Accommodation Influencing Factors

XIE Guohui, LUAN Fengkui, LI Nana, WANG Qingran

2018, 51(11):  125-131.  DOI: 10.11930/j.issn.1004-9649.201803026

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Evaluating the contributions of the new energy accommodation influencing factors of is one of the most important issues to improve the current consumption status. This paper summarized the current achievements of China new energy accommodation in 2017, analyzed the major influencing factors of new energy accommodation from the perspectives of power mix, power grid, load and market mechanism. The influencing factors contribution evaluating model was established based on chronological production simulation. Taking Gansu wind power accommodation as an example, the contribution of various factors to promote wind power consumption was studied. The results showed that, Gansu wind power accommodation had great achievements with the joint efforts of all factors, including power load increase, cross-district deliberating, generation exchange different provinces, power reverse capacity shared, captive plant exchange trade and so on. The largest contribution was the power load increment and followed by cross-district deliberating and power reverse capacity shared.

Maximum Power Point Tracking for Photovoltaic Systems Based On Exponential Variable Step Size Incremental Conductance Algorithm

TU Yanan, YU Aiqing, XUE Hua, WANG Yufei

2018, 51(11):  132-138.  DOI: 10.11930/j.issn.1004-9649.201803193

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Photovoltaic maximum power point tracking algorithms are designed to maximize the usage of electricity generated by photovoltaic cells, which has become a research hotspot to improve the operational efficiency of photovoltaic power generation system and reduce the cost of photovoltaic energy. In this paper, the existing drawbacks are first analyzed such as slow convergence, steady-state oscillation, falling into local optimum and the low efficiency of photovoltaic power generation. Secondly, an exponential variable step size incremental conductance algorithm with threshold value criteria and variable step size is proposed. In addition to the rapid tracing advantage inherited from conventional incremental conductance algorithm, the approach proposed in this paper can track the global maximum power point accurately and stably. Finally, simulation experiments under different operating conditions were carried out to verify the feasibility and applicability of the above algorithm.

Survey of Inspection Technology of Overhead Transmission Line Robot Based on Computer Vision

LI Zhenyu, GUO Rui, LAI Qiupin, YANG Jun, YONG Min, WANG Liang, FU Siyao

2018, 51(11):  139-146.  DOI: 10.11930/j.issn.1004-9649.201801094

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Overhead transmission lines are the key to safe operation of power grid and reliable transmission of electric power, and it is very important to carry out regular inspection. The computer vision system has the characteristics of high integration, good interactivity, high degree of automation and fast processing speed, it can play an important role in the accurate identification and fault judgment of all kinds of equipment during the inspection process of overhead transmission lines, therefore, the computer vision system has a wide range of applications in the overhead transmission line robot inspection and fault diagnosis. In this paper, the robot computer vision inspection technology and its research status are summarized from the aspects of wire identification, tower identification and insulator string identification, the corresponding image processing methods are analyzed, on this basis, the overhead transmission line robot visual inspection key technology has been summarized and foreseen.

Refined Method of VLAN Configuration for Smart Substation

WANG Dong, HE Ruiwen, JIANG Qingyun

2018, 51(11):  147-153.  DOI: 10.11930/j.issn.1004-9649.201801095

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In order to solve the uncertainty problem of network performance caused by the lack of uniform standard, that especially relates to virtual local area network (VLAN) partitioning and configuration, a double adjacency condition search algorithm is proposed to determine the message transmission path through the switch port. For clarifying the mechanism of VLAN, the VLAN division scheme based on Source-Sink and the switch port setting rules based on Trunk-Hybrid/Hybrid-Hybrid(T-H/H-H) are proposed. Through setting the configuration of the VLAN with a determined message transmission paths, the network traffic is optimized. The simulation shows that the optimization effect of the refinement method is more idealized compared with that of other methods. Meanwhile, the flow distribution can be controlled effectively with this practical method.

Prospect of Application of Edge Computing in the Field of Supply and Demand

LI Bin, JIA Bincheng, CHEN Songsong, YANG Bin, SUN Yi, QI Bing

2018, 51(11):  154-162.  DOI: 10.11930/j.issn.1004-9649.201712051

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With the intellectualization of equipment in the supply and demand field, the amount of information transferred between supply and demand areas is increasing, resulting in waste of bandwidth resources and information processed not in time. The introduction of edge computing into the supply and demand field is a good solution to these problems. This paper discusses the emergence and advantages of edge computing. Then it analyzed the supply and demand interaction and explained the demand for edge computing in the supply and demand field. Finally, this paper looks forward to the application of edge computing in the field of supply and demand. And the application of edge computing in the specific scene of supply and demand is built in this paper, which provides reference for the development of edge computing in the field of supply and demand.

Investigation on the Status of the Reconstructive Projects for SCR De-NO_x Under the Condition of Ultra-low Emission

YAN Min, ZHANG Yang, ZHU Yue, JIANG Jianpingg

2018, 51(11):  163-167.  DOI: 10.11930/j.issn.1004-9649.201801033

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In order to meet the requirements of the Plan of Action for Energy-saving and Emission-reduction upgrading and Reconstruction of Coal and Power plants (2014-2020), reconstructive projects of ultra-low emissions have been carried out in many coal-fired power plants. To provide reference for the design and construction of flue gas denitration for ultra-low emission units, investigation on the catalyst status is conducted for 132 units in 49 power plants whose flue gas denitration ultra low emission retrofits had been completed. The unit type, flue gas temperature, inlet dust concentration, inlet NO_x concentration and modification of catalysts are analyzed. The catalyst volumes before and after the ultra-low emission retrofit are compared. At the same time, some proposals based on case analysis are given to guarantee the security and economical operation and the standardized NO_x emission.

Research and Improvement on Activity Detection Method for Plate-type De-NO_x Catalyst

YAO Jie, SHEN Lei

2018, 51(11):  168-173.  DOI: 10.11930/j.issn.1004-9649.201806045

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At present, although activity detection of the plate-type De-NO_x catalyst is carried out primarily with reference to methods specified in the domestic and international standards, there have been some issues in existence in practice, such as limited scope of applications and poor detection precision. In this article, the features and existing problems in traditional detection modes are analyzed, then the improvements and optimization procedures are provided to not only enhance the accuracy of activity detection but also make comparison among plate-type De-NO_x catalysts from various production batches and manufacturers. The efforts to improve detection methods are demonstrated through a series of practice tests. The study outcome indicated that, improved detection methods solved the De-NO_x activities comparability problem between plate-type De-NO_x catalysts of different types. Also the defect of structural instability in detecting unit with traditional methods is effectively improved, which resulted in significant promotion in the aspects of the detection precision, accuracy and repeatability.

Correction Factor Investigation for Droplet Testing in Wet Flue Gas Desulfurization System

JIA Xibu

2018, 51(11):  174-178.  DOI: 10.11930/j.issn.1004-9649.201706173

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As the thermal power companies have gradually completed their ultra clean emission renovations, it becomes impractical to still use the correction factor in current national standards to examine and demonstrate the droplet testing results at the desulfurizer outlet. In this paper, the method to correct the droplet testing results based on the correction factor of solid content concentration is proposed. The new method takes the solid quantity in the actual droplet into consideration and the interference from the condensation water to the droplet mass concentration can be avoided. The proposed method has three main features, i.e. (1) it is consistent with the demister operating principles and the testing process is straightforward; (2) it is practical for lab analysis and can improve the applicability of the existing standard, which can be a reference for future projects; (3) it is ensures the fairness of demister performance evaluation, and is good for further and deeper analysis on the demister performance as well.

Study on Desulfurization Wastewater Treatment for the Power Plant with Seawater Cooling System

LU Jian, LI Yajuan, XU Zhen, HU Dalong, JIANG Xiaoyan

2018, 51(11):  179-184.  DOI: 10.11930/j.issn.1004-9649.201708223

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All industrial wastewater has been treated and reused at one coal-fired power plant with once-through cooling system except the desulphurization wastewater. In order to achieve the goal of zero discharge of wastewater, the desulfurization wastewater treatment is studied in this paper with the technique consisting of microfiltration (MF), reverse osmosis (RO), and electro-dialysis (ED) processes. The results show that at the RO recovery rate of 75%, the desalination rate is over 99% and the removal rates is over 90% for Ca²⁺, Mg²⁺, SO₄^2– and other divalent ions. After being concentrated by ED, the salt content increased from 7% to 21%. Ultimately, the effluent volume decreased from 20 m³/h to 2 m³/h, which could significantly reduce the cost of crystallization equipment and energy consumption. After the implementation of this plan, the utilization factor of water resource could be improved and the target of zero discharge of wastewater will be achieved.