Table of Content

25 August 2017, Volume 50 Issue 8

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Special Contribution

Development of Factory-Composited Insulators for Improving UHV Grid Configuration Quality

CHEN Yuan, WU Guangya, YE Tinglu, GAO Haifeng, GAO Shunan, SU Jianjun, XIA Yanwei, SONG Furu, ZHOU Guohua, YANG Jing, LUO Yongqin, SHAN Huaping, LU Yi, NIU Biao, WANG Xin, ZHANG Xu, FAN Shuochao, ZHAO Yuan

2017, 50(8):  1-15.  DOI: 10.11930/j.issn.1004-9649.2017.08.001.15

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In this paper, the factory-composited insulators developed by combining the conventional porcelain or glass insulators with high quality RTV coating is proposed to change the RTV coating as a temporary anti-pollution-flashover measure into a permanent one. A new mature external-insulation selection at the design and construction stage of power transmission project is provided, which breaks through the application limit of porcelain and glass insulators used in heavy pollution area as to eventually improve the comprehensive quality of UHV grid. Based on the application experience and test data, the product parameters and design principles of factory-composited insulators are put forward, and the distrust of RTV is clarified.

Column of Instrument & Control

Analysis and Pre-control Measures of Typical Faults of the Thermal Control Systems in the Power Plants Nationwide in 2016

HUA Guojun

2017, 50(8):  16-21.  DOI: 10.11930/j.issn.1004-9649.2017.08.016.06

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This paper conducts the statistical analysis on 123 typical cases of unit trip caused by the thermal control systems in the power generation enterprises nationwide in 2016. It concludes that the fault causes involve the system design and configuration, installation, maintenance and operation. Through the analysis, the pre-control measures to eliminate the potential risks are discussed from the aspects of the optimization of the control logics, the normalization of the systematic and technical management and the enhancement of the reliabilities of the thermal control system to further improve the security of the system, prevent the units from tripping and improve the reliabilities of the operation of the generation units and the power grids.

Research on and Application of the Control Strategy for Flexibility Improvement of Supercritical Fossil-Fired Power Units

GONG Guangzheng

2017, 50(8):  22-26.  DOI: 10.11930/j.issn.1004-9649.2017.08.022.05

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Along with the increasing of new energy generation projects and long distance power supply volume beyond the area, the power supply structure of power grids has undergone fundamental changes, which brings about growing pressure on peak load regulation. Therefore, the modification on the flexibility of automatic control is required. In this paper, based on the analysis of the characteristics of the power grid AGC instructions and the study on the control characteristics of the supercritical units, a series of control strategies are proposed in accordance with the requirements of power grids to improve the load response rate of the unit under the condition of large loads, avoid the impacts of the slight fluctuation of the AGC commands on the unit control and enhance the stability of the reheat steam temperature control. The practical application proves that the optimized coordinated control system can maintain the stability of major thermal parameters and meet the requirements of the power grids for the enhancement of the flexibility of the unit operation.

Primary Frequency Regulation of Large Frequency-Difference in Supercritical/Ultra-Supercritical Units After UHVDC Transmission System Block Fault

FEI Zhangsheng, LU Honglin, HE Yongjun, GUI Yishu

2017, 50(8):  27-31.  DOI: 10.11930/j.issn.1004-9649.2017.08.027.05

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When the DC blocking fault occurs in the UHVDC transmission system, the instantaneous power loss in the receiving power grid relies on the power plant primary frequency regulation in the region for compensation, and the thermal power unit plays a very important role. Presently, most thermal power units are of high capacity and high parameters with very limited energy storage capacity. In the large frequency-difference primary frequency regulation triggered by the DC blocking failure of the power grid, the power contribution of the thermal power unit is affected by the energy storage of the unit, which is not conducive to the rapid recovery of the power grid accident and may cause grid frequency oscillation. In this paper, the Tianji Power Plant of Sending Power from Anhui to the East Project is taken as an example of the typical 600 MW thermal power units to conduct the testings on primary frequency regulation of large-frequency difference and the optimization of related coordination control strategies. A variety of new control strategies are adopted to improve the unit coordinated control and the primary frequency performance so as to increase the contribution of thermal power units to the power grid during faults.

Research and Test of the Primary Frequency Control in Ultra-Supercritical Units Under Feed Water Bypass Control of HP Heater

CHEN Bo, ZHOU Shenxue, DING Ning, SU Ye, ZHU Bingquan, YIN Feng, DING Junhong

2017, 50(8):  32-36.  DOI: 10.11930/j.issn.1004-9649.2017.08.032.05

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Based on the implementation of the feed water bypass of the HP heater in a 1 050 MW ultra-supercritical power unit, this paper introduces the primary frequency test at the maximum regulating capacity under the feed water bypass control mode. In the test, the characteristics of feed water bypass control regulation at the designed value are obtained and compared with those of combined regulation methods. According to the load response characteristics, the feed water temperature falling of the economizer inlet and outlet and the utilization efficiency of the boiler thermal storage, the boundary conditions of the primary frequency regulation operation are discussed under the feed water bypass control mode. At last the energy-saving hybrid frequency modulation scheme is proposed for the ultra- supercritical unit. The study results provide experimental evidence for excavating the regenerative potential of the ultra-supercritical unit and for the exploration of the primary frequency modulation capability enhancement of the ultra-supercritical power generation unit in the UHV receiving end power grid.

Research on and Application of Multiplier Predictive Function Control Over Main Steam Temperature

LI Quan, YIN Feng, ZHANG Zhengwei, HOU Guolian, LUO Zhihao

2017, 50(8):  37-40.  DOI: 10.11930/j.issn.1004-9649.2017.08.037.04

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This paper proposes a multiplier predictive function control method for the first order plus pure delay object. When the step function is adopted, the optimal control law is obtained. In this control law, the optimal time domain is exponential. Moreover, the paper also proposes multiplier coefficient and calls it predictive adjusting coefficient to simplify the corrected output of the controlled object as the output of the actual controlled object. Thus the optimal control law of multiplier predictive function control is obtained. Generally, the cascade control is adopted in the main steam temperature control system with leading and idle zones, and the main controller is replaced with the multiplier predictive function controller In this paper, a linear correction method for the desuperheater control valve is proposed. The practical applications show that the method presented in this paper is simple and effective, and valuable for popularization.

Research on Pilot Scale Generalization Modeling Method for Power Supply Side Experiment of Power Grid Based on the Online Thermal Performance Data

MA Rui, HOU Qian, JIN Fei, YANG Chunlai, PENG Gang

2017, 50(8):  41-47.  DOI: 10.11930/j.issn.1004-9649.2017.08.041.07

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Aiming at the defect that the current power plant mechanism simulation model cannot be applied to direct the actual production process, this paper proposes the thermal performance data enhanced incentive simulation modeling and third-order transfer function identification method, and develops a standard experimental platform for power supply side coordinated control production experiment. Starting with the integration of the online data and the simulation algorithm of the power plant unit, the enhanced validation and simulation platform is established which highly simulates the performance of the actual power plant. Through the mechanism model, the three order transfer function of response characteristics of the actual production process is determined with the parameters being optimized until the model precision meets the practical verification requirements. The simulation results show that the RUNBACK production experimental model established by this method can meet the precision requirements of actual production. The proximity of the response characteristics of the simulation model to the actual characteristics reaches 90% , which makes the simulation platform an ideal technical support platform that can truly serve the need for production experiment and conduct the predictive assessment on the effects of production experiment. With both generality and practicality, this method can provide a new way for unit simulation toward practical applications.

The Research and Application of Thermal Control Simulation Test Device for Optimization of Advanced Thermal Control Scheme

YANG Minghua

2017, 50(8):  48-52.  DOI: 10.11930/j.issn.1004-9649.2017.08.048.05

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To address the lack of simple and effective testing methods during the current research process of advanced thermal control strategies, the thermal control simulation test device is developed based on the minimum distributed control system using high precision simulation technology. The device, which has good stability and extendibility, can be widely used for thermal control logic optimization and personnel training. Then, aiming at the poor tuning precision of the coordinated control system(CCS) of a 600 MW supercritical unit, an optimization scheme is proposed and tested on the established simulation device. The result of simulation shows that the precision and accuracy of the CCS are improved by applying the proposed optimization scheme. The success of the optimization case shows that the developed thermal control simulation test device can meet the requirements of advanced thermal control scheme test, and provide a way for advanced thermal control scheme testing and relevant scientific researches.

Construction of Information Security Protection System for Industrial Control System in Taizhou 2nd Power Plant

ZHOU Shenxue, FAN Yuan, XIA Kechao, YIN Feng, HU Boyong, DU Yongchun

2017, 50(8):  53-57.  DOI: 10.11930/j.issn.1004-9649.2017.08.053.05

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This paper studies the characteristics and requirements of the industrial control system in electric power industry, and analyzes the risks in the information security of the industrial control system in Zhejiang Zheneng Taizhou Second Power Generation Co., Ltd., (hereinafter referred to as“Taizhou 2nd power plant”). Based on the research on the relevant regulations of information security protection in the power industry, the paper proposes an information security protection scheme from the aspects of network protection, protocol security, equipment protection and management to develop and construct the information security protection system for the power plant such that the information security of the control system in the power plant is successfully enhanced, which is of great referential significance for other power plants in the information security protection construction of industrial control system.

Generation Technology

Fault Diagnosis and Treatment of the Generator Vibration of a 660 MW Unit During Trial Operation Period

ZHU Xiaodong, WU Zhengfeng, TAN Xiu, CHEN Bo, LIU Ting

2017, 50(8):  58-62.  DOI: 10.11930/j.issn.1004-9649.2017.08.058.05

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During the trial operation of a 660 MW supercritical unit, the generator shaft and bearing vibrations rise abnormally during the loading stage. By tracking the changes in the generator bearing vibrations, a testing scheme is formulated and implemented. Based on the analysis on the operation and test data, the fault diagnosis on the generator bearing vibrations is conducted, which concludes that the thermal unbalance from the generator rotor coil asymmetric expansion causes the abnormal vibrations. According to the diagnostic result and by taking the site situation into account, counterweights are added to the low pressure Rotor 2 and the generator connecting wheel to carry out high speed dynamic balancing. The dynamic balancing results show that the generator bearing vibration is then effectively reduced with the turbine bearing vibration also kept in favorable range.

Research on Operation of Swirl-Opposed Firing Boiler Retrofitted for Low NO_x Emission

LIU Qingwei, GUO Zhiming, LU Ye, REN Lili, DU Daquan

2017, 50(8):  63-67.  DOI: 10.11930/j.issn.1004-9649.2017.08.063.05

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The emission of NO_x decreased obviously after the transformation with low NO_x burner (LNB) for a 600 MW unit. However, there are some problems during the process in operation, such as overheating of the reheater, the high oxygen deviation and the high NO_x emission under high power loads. The problems are discussed in this paper and some improvement measures are proposed to ensure the efficiency and safety of LNB.

Study on Steam Oxide Microstructure Morphology and Exfoliation Sensitivity of High- Temperature Heating Surface of Boilers

HUANG Xingde, XU Kun, YANG Xingang, YOU Zhe, ZHAO Hong

2017, 50(8):  68-72.  DOI: 10.11930/j.issn.1004-9649.2017.08.068.05

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The microstructure of the oxide scale contains a wealth of information about plane grain morphology and section structure. Research suggests that the exfoliation sensitivity is closely related to the microstructure of the oxide scale. Through the comparison between the oxide scale microstructures of various materials under different operating conditions (i. e. operation duration, temperature and mode)and chemical conditions, the embeddedness property of grain can be extracted from the grain type and size, column shaft and fancet of the planar grain morphology. The profile layer structure characteristics can be characterized by its thickness, delamination and void content. the combination of the two dimensional information can be integrated together to comprehensively determine the growth stage and exfoliation sensitivity, so as to provide decision-making basis for predicting and preventing the damage of the oxide.

The Parallel Processing and Running of the Steam-Driven Induced Draft Fan for a 660 MW Ultra-Supercritical Unit

WANG Dundun, YANG Jianfeng, DUAN Xuenong, YU Pengfeng, CHEN Xun, YANG Yi

2017, 50(8):  73-77.  DOI: 10.11930/j.issn.1004-9649.2017.08.073.05

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The steam-driven induced draft fan has the advantages of no starting current, low auxiliary power ratio and efficient adjustment and it is gradually got applied in newly-built units. In this paper, the steam-driven induced draft fan of a new ultra-supercritical unit is taken as the study object. According to the characteristic curves of the fan and the pipeline, the optimal parallel working conditions are analyzed, and the parallel method and the operation strategy for postparallel running are presented. Aiming at the problems of insufficient margin, high exhaust pressure and poor regulation characteristics in the operation of the fan, the cause analysis and the control logic optimization are carried out to ensure the safety and stability of the unit.

Application Study on the Treatment of Steam Turbine Salt Deposit in Case Closing Condition

WEN Huifeng, LONG Guojun, YAO Jiantao, CAO Jieyu, LIU Yongbing, DANG Zhijun

2017, 50(8):  78-81.  DOI: 10.11930/j.issn.1004-9649.2017.08.078.04

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The sea water leakage in condenser will cause salt deposition on the steam turbine unless it is well handled in time. The consequence may become even worse such that the normal operation of the unit will be affected. This kind of problem occurred in a 330 MW power plant before. The steam-water quality deteriorated with the Na⁺ mass concentration of every sampling points exceeding 1 000 μg/L after the sea water leaked into the condensate system. Thus the generation unit had to be shut down due to the load limit. In this paper, the analysis concludes that the problem is caused by the salt deposition on the steam turbine, with soluble NaCl as the major ingredient. Then it is decided to clean the turbine with supersaturated steam without opening the cylinder case. After such cleaning procedures, the content of NaCl on all parts of the turbine is reduced to less than 0.07 g/m². In addition, after startup of the unit for 14 hours, the steam-water quality meets all the requirements of GB/T 12145—2016 Quality criterion of water and steam for generating unit and steam power equipment, and the unit can operate at full load when it is connected to the power grid. The practice shows that the salt deposition on turbines induced by sea water leakage into the condenser can be cleaned by using supersaturated steam, which is proved to be economical, effective and easy to implement.

Safety Evaluation and Lifespan Prediction of Low Hardness P91 Pipes

YANG Chao, TANG Chunpo, GONG Hongqiang, SUN Xiong

2017, 50(8):  82-86.  DOI: 10.11930/j.issn.1004-9649.2017.08.082.05

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In order to ensure the safety of the piping and equipment used in the thermal system, the creep rupture test is carried out at 570 ℃ on the P91 specimens with different hardness. The test results are fitted by the logarithmic functionfor safety evaluation and lifespan prediction of the P91 pipe, such that the overestimation on long-term creep rupture caused by isothermal extrapolation method can be avoided. The study results show that for low hardness P91 pipe fittings, the creep rupture of 570 ℃/1×10⁵ h tends to drop with the decrease of hardness. Especially when the hardness goes down below 165 HBW, the creep rupture strength of P91 steel will decrease below the material allowable stress, which means its long-term safe operation cannot be ensured. The P91 pipes in operation with low parameter settings have a larger strength margin, and its hardness is allowed to be lower to some extents. However, for the main steam pipeline operated at 570 ℃, especially without thickening designed bend, the strength margin is very low. Therefore, the safety evaluation and lifespan prediction is compulsory.

Power System

The Impact of Grid Parameters on Transient Stability

SONG Junying, WANG Weiyu, JIANG Xuejiao, LI Xinran, ZUO Yu, HUANG Yun

2017, 50(8):  87-92.  DOI: 10.11930/j.issn.1004-9649.2017.08.087.06

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Power system is composed of many different types of components. Different component parameters have different impacts on power system transient stability. A comprehensive analysis is performed on impacts of grid parameters. The analysis is based on transient stability measure indexes weighted by electrical betweenness. According to proposed transient stability indices, a Central China province 500 kV power grid is modeled and analyzed in PSASP. The transformers and transmission lines are evaluated per ranking of proposed transient stability indices. The simulation results validate the effectiveness of proposed indices.

Use OWTS to Detect Insulation Damage in XLPE Cable Body

HE Wenrong, HE Xiaowan, ZHENG Shanshan, SONG Xin, ZHAO Yong, WEI Erbing

2017, 50(8):  93-97.  DOI: 10.11930/j.issn.1004-9649.2017.08.093.05

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This paper analyzed and summarized the fault type and test method about the medium voltage XLPE cable. Find that the researches about fault types and test methods for cable middleware and terminal are more than the cable body. Then, reproduced the fault of insulation damage in XLPE cable body artificially and tested it, focused on the fault model of insulation damage with copper tape shield and semiconducting tape fault, described the processing of experiment with OWTS method in detail, analyzed the result, located the partial discharge position. It illustrated that the OWTS system can detect and locate the damage in XLPE cable body effectively. This provided a method and a basis for XLPE cable maintenance and testing.

Research on the Relationship Between Electric Energy Meter Fault and Regional Climate & Load in Different Industries

XUE Yang, DU Xingang, ZHANG Penghe, ZHANG Jiahai, ZOU Yuhan, PENG Chuning

2017, 50(8):  98-105.  DOI: 10.11930/j.issn.1004-9649.2017.08.098.08

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Based on collection, quantification and cluster analysis of climate and power grid load data in operation and maintenance area of electric energy meter, meter operation regions are divided by climatic characteristics and user industry are classified by load characteristics. The clustering method is validated by statistical data of energy meter fault in each region and electricity industry. Six regions are classified according to climate severity as basis for electric energy meter selection. The description and study of the load characteristics, started with seven kinds of loads which have greater impact on meter fault, facilitates research of meter fault and failure mechanism under laboratory condition. Those analyses can not only improve component selection, design and production process, but also reduce electric energy meter fault rate.

Research on Lightning Performance of 220 kV Split-Level Cross Arm Tower in Mountainous Area

HUANG Peng, WU Kun, WANG Pei, FANG Zhenggang, SUN Haifeng

2017, 50(8):  106-112.  DOI: 10.11930/j.issn.1004-9649.2017.08.106.07

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Aiming at the problem in mountainous terrain slope affect lightning protection performance of a tower, a new type of 220 kV split-level cross arm tower is designed to reduce the lighting trip-out rate of mountain transmission lines. Lightning protection performance of split-level cross arm tower under different slope conditions are analyzed to determine the feasibility of split-level cross arm tower in mountainous area. Multi-wave impedance model of the tower and equivalent circuit model of grounding electrode are established; the complete model for the tower is built based on PSCAD, and the rate of lightning back striking is calculated; modified electrical geometry model is established for solving the shielding failure rate of the new tower, and the calculation formulation is derived based on the geometric model; lightning trip-out rate of split-level cross arm tower under several slope conditions are analyzed and compared. Compared with the conventional tower, the new type split-level cross arm tower can improve the lightning withstand level of the tower effectively. Research results can provide references and basis to lightning protection in the design period and the reconstruction of transmission line in mountainous area.

Identification and Location of Single-Phase Line-Broken Fault of Arc-Suppression Coil Grounding System

JU Yong'an, LIU Cong, SHAN Rutao, TAN Wengang, WANG Fei, NI Chunlei

2017, 50(8):  113-117.  DOI: 10.11930/j.issn.1004-9649.2017.08.113.05

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In the 66 kV neutral point arc-suppression coil grounding system, single-phase line-broken fault occurs frequently on the overhead transmission lines, which leads to illusory grounding phenomenon, and it is hard to distinguish between single-phase line-broken fault and single-phase grounding fault by the traditional three-phase voltage characteristic method. In this paper, a theoretical analysis is made of the single-phase line-broken faults and the causes for illusory grounding phenomenon based on case studies of such faults. Based on a detail comparison of the single-phase grounding fault and the single-phase line-broken fault occurring in 10 kV busbars, a fault identification location method is proposed for system operators to identify the fault types and their locations.

Improvement and Application of Static Security On-Line Correction Strategy Based on Grid Division Identification

NING Jian

2017, 50(8):  118-124.  DOI: 10.11930/j.issn.1004-9649.2017.08.118.07

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The static security analysis is one of the core functions of real-time monitoring and early warning application in the smart grid dispatching control system. The correction information by single component disconnection is restricted to sensitivity which is too simple to cover actual needs. Based on an in-depth analysis of grid division's characteristics, an online identification technology is raised based upon tree search method, and an improvement is made on the static security on-line correction strategy, which can provide a real time decision-making information of division connection device's loop closure aiming at over-limit correction of devices. The technology is realized and put into operation in dispatching control system of North China power grid. Practical verification shows that the analysis and calculation results are accurate and reliable, and the technology can improve the intelligent and automatic level of online-analysis applications.

Improved Steam Turbine Power and Load Unbalance Protection and Parameter Setting

AI Dongping, LI Yingkai, YANG Xi, WANG Zhonghua, TAO Xiangyu, CHEN Tao, WANG Liangyi

2017, 50(8):  125-128.  DOI: 10.11930/j.issn.1004-9649.2017.08.125.04

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An analysis of the malfunction of PLU protection of steam turbines in China shows that the PLU protection based on the mechanical power and the electric power imbalance has malfunction risks caused by grid faults. In order to solve this problem, a simulation model for stability analysis is established by introducing the speed constraint into the PLU protection, and the principles for setting the rotating speed constraints are proposed. Based on the regional power grids, the typical faults are used to configure the speed constraint parameter. The simulation result verifies that this method can effectively prevent the PLU malfunction and improve the reliability of PLU protection.

Research on Energy Consumption of Guangdong Urban Residents Under the Background of Energy Conservation and Emissions Reduction

CHEN Zheng, LENG Yuan, ZHANG Xiang, SONG Yihang, MENG Wenchuan

2017, 50(8):  129-134.  DOI: 10.11930/j.issn.1004-9649.2017.08.129.06

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For a long time, research on energy conservation is mostly focused on industry sector, while the research on energy consumption of residents is not deep enough. With the improvement of resident's living and strong promotion of urbanization, the energy consumption of urban residents is increasing rapidly and has become the key sector of energy consumption in whole society. Therefore, the energy consumption efficiency of urban residents has significant impacts on energy conservation of the whole society. By taking the energy consumption of urban residents in Guangdong province for case study, the total amount and structure of energy consumption of urban residents in Guangdong province are studied based on the LEAP model by using the scenario analysis method, which can provide a basis for establishing a sustainable resident's energy consumption mode, and a decision-making reference for formulating relevant policies on resident's energy conservation.

Information and Communication

Application of Satellite Communication in Survey and Control of Large UAV Transmission

WU Feilong

2017, 50(8):  135-140.  DOI: 10.11930/j.issn.1004-9649.2017.08.135.06

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Aiming at the bottleneck of measurement and control communication technology for large UAV transmission line inspection, this paper proposes a point-to-point satellite communication solution by analyzing and comparing various schemes. In the implementation of the technical scheme, the optimal selection and installation position of the airborne antennas are analyzed. The dual transmission diversity is used for forward transmission while the way of detecting the energy of the receiving signals is used for reverse transmission, which has effectively solved the signal blockage problems of satellite communication system by the helicopter rotors, resulting in the communication link interruption. The proposed method can effectively promote the application of large UAVs in power transmission line inspection, and further expands the use of satellite communication technology in civilian and military purposes.

Research and Application of Smart Substation Configuration File Online Control Based on Network Analyzer

WANG Xiaoli, LIU Haitao, ZHANG Xufeng, SHI Yu

2017, 50(8):  141-145.  DOI: 10.11930/j.issn.1004-9649.2017.08.141.05

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Some provincial power companies in China have developed operation management system of configuration files for smart substation so as to make a control management of such files as SCD, CID, CCD and ICD. However, there are still some inconformity problems between control configuration files and field device configuration files. Based on the characteristics of the network analyzer in real-time operation and the reliable communication of the total station secondary equipment, such means as packet analysis, service analysis, network node changes and check code are used to make a real time comparative analysis of the device configuration files and archive configuration files so as to realize the three-dimensional control of configuration files from the substation end to dispatching end, and the online and off-line multi-dimension and seamless control of configuration files. In this way, the safety level of smart substa-tions is improved.

Research and Application of Information System Fault Automatic Recovery Technology Based on BP Neural Network

YAN Longchuan, ZHANG Xiaoliang, YANG Meng, LIU Dongmei

2017, 50(8):  146-149.  DOI: 10.11930/j.issn.1004-9649.2017.08.146.04

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There are a large number of information system equipments in data center. It is so often that fault of single device hardware or software occurs. In order to protect the business continued service, the rapid recovery and automatic processing of the fault is necessary.In this paper, we mainly study the automatic recovery technology of the information system, and use the BP neural network to evaluate the software and hardware status and to predict the system capacity. An automatic disposal script set is constructed. Combined with the problem processing knowledge base on system status and script matching, the automatic recovery of the typical problems of information system is realized. From our experiments, the proposed method is feasible and can be used in data center.

System of Partial Discharge Detection Using IoT Technology

CHEN Minwei, CHEN Bin, YE Zhaoping, SHI Zhiming

2017, 50(8):  150-157.  DOI: 10.11930/j.issn.1004-9649.2017.08.150.08

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Using internet of things technology to develop a mobile, free installation and wireless substation equipment of partial discharge detection system. The system integrates the predetection, live detection and online detection as a whole, and uses the advantage of three detection mode fully, while uses the wireless, IP and miniaturization technology etc. In order to verify the effectiveness of the system, the ultra high frequency, ultrasonic, transient voltage and frequency detection were carried out. The experimental results show that the system realizes a new breakthrough of the detection methods and means, and improves the work efficiency meanwhile ensures the detection quality.

Energy Conservation and Environmental Protection

Research on the Implementation of Energy Saving and Ultra Low Emission Technique in W-Flame Boilers in Guizhou Province

ZHU Zhi

2017, 50(8):  158-162.  DOI: 10.11930/j.issn.1004-9649.2017.08.158.05

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According to the upgrading and enhancement plan issued by the state for energy saving and emission reduction, all the thermal power generation units nationwide must meet the standard of energy saving and ultra-low emission during the 13th Five-Year Plan period. In order to figure out how to implement the plan for the supercritical units with W-type-flame boiler in Guizhou Province, the energy consumption data are collected for the same type of boilers that have already been put into operation. Then the level of energy consumption is compared and analyzed. In addition, the investment and operation costs of ultra-low emission modification are analyzed for the in-service units in the province through case studies. The results show that there are certain specialties of the W-type flame boilers in Guizhou, which means that the modification is more difficult and expensive in comparison with other provinces. The operation costs after modification will also increase more. Therefore, it is recommended that the policy support should be strengthened.

Effect of SCR Catalyst Activity Evaluation on Ultra Low Emission of NO_x

LI Shuaiying, WU Baohui, YAO Hao, NIU Guoping, WANG Xiaobing, HUANG Gangying, ZHANG Lide, LU Xiaofeng, LIU Yi

2017, 50(8):  163-167.  DOI: 10.11930/j.issn.1004-9649.2017.08.163.05

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The catalyst is the key material in SCR denitrification technology, which plays the indispensable role to realize NO_x ultra-low emission. However, depending on the practical operation conditions and the coal quality, the attenuation law of the catalyst activity will deviate from the theoretical curve. In this paper, the chemical lifetime of the catalyst is predicted by applying a mathematical model. In combination with the actual cases, the efficiency of catalyst layers and the selection of the catalyst are studied. The results show that in the ultra-low emission modifications, the catalyst activity evaluation is very critical to the selection of the catalyst. It may affect the stable operation of the equipment and the cost of the investment.

Development and Industrial Experiment Research of Environment-Friendly Coal Flow Dust Suppressant Agent

LIN Musong, MA Lei, LI Yuchun, CHEN Wenzhong, RAO Guangwei

2017, 50(8):  168-172.  DOI: 10.11930/j.issn.1004-9649.2017.08.168.05

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The coal conveying system is actually one of working places with coal dust pollutions in thermal power plants. Therefore it is necessary to safeguard the employees' health and protect the environment by applying dust suppressant agent. In this paper, based on the study on the mechanism of dust emission of coal flow and the characteristics of coal dust, a new type of environment-friendly dust suppression reagent is developed, which is composed of polyanionic cellulose and lubricant. The industrial testing results show that firstly, the dust suppression reagent is very effective in dust-controlling. Compared with spraying water, when the coal flow is 1 000 t/h, with the same spraying volume of 45 mL/s, the dust suppression agent can reduce the coal conveying belt advection dust emission by 75% and the downstream dust emission by 70%, that is, the coal dust concentration drops from 1.838 mg/m³ to 0.460 mg/m³ and from 1.936 mg/m³ to 0.580 mg/m³ respectively. Secondly, since the amount of suppression reagent is very small, it has hardly any substantial effect on the total moisture of coal. Upon examination, the dust suppression agent is non-toxic and harmless, which is completely applicable for coal flow dust control.

New Energy

Study on the Control of New Energy Electric Vehicles Participating Freguency Regulation of the Grid

ZHANG Min, PENG Mengni, XIA Xiangyang, KONG Xiangji, LI Mingde, HUANG Hai, TANG Jie

2017, 50(8):  173-178.  DOI: 10.11930/j.issn.1004-9649.2017.08.173.06

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With the commercialization of electric cars, electric cars and grid connected V2G(vehicle to grid) between the influence is also of concern. Large capacity storage electric vehicle equipped with the device can be very good to be distributed network storage device. In this paper through the electric car connected to the grid, to solve the grid frequency deviation caused by power fluctuation of distributed energy. For electric vehicles using the preset smart charging control, will be in the idle state of the electric car charging pile together. Through the power grid for two-way transmission, in order to restrain the power frequency offset. Through the simulation analysis, the number of electric cars in a certain area is large enough, can effectively inhibit the frequency offset in regional power grid.

Research on Optimum Tilt Angle and North-South Step Tracking for PV Panel in Guangzhou

WANG Lei, ZHU Zengwei, PAN Wuchun, WANG Ding, NI Haoyi, ZHANG Zhen

2017, 50(8):  179-184.  DOI: 10.11930/j.issn.1004-9649.2017.08.179.06

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Depending on solar radiation calculation mode for inclined PV panel, yearly global radiation on surfaces tilt at different angles were calculated on several years. Historicaly change was obtained on optimum tilt angle. Yearly north-south step tracking for PV panels were researched by two, four, twelve steps according to different intervals like half year, season and month. Optimum tilt angels and corresponding radiation plus for different tracking time intervals and the whole year were calculated. To maximize yealy global radiation, the effects of different install modes were analyzed.