Table of Content

20 April 2017, Volume 50 Issue 4

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Special Contribution

Progress and Development Trend of Electric Power Construction Technology in China Part Ⅱ-Power Source

SUN Xin

2017, 50(4):  1-5.  DOI: 10.11930/j.issn.1004-9649.2017.04.001.05

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The development and planning of the electric power industry will eventually be applied to the construction of the project. The power construction technology has laid a solid foundation for the development of China’s electric power industry. This paper summarizes the latest research results and important engineering practice in the field of power construction during the period of 12th Five-Year, including the large capacity and high parameter coal-fired power generation project, coal-fired ultra low emission technology, wind power technology, solar power technology, energy storage technology, and power construction management. This paper analyzes the parameters and technical level of the above technologies may be reached in the “13th Five-Year” period and a longer period of time.

Electricity Market Construction Experience of Major Provinces of Energy in China

ZHANG Lizi, XU Chuanlong

2017, 50(4):  7-10.  DOI: 10.11930/j.issn.1004-9649.2017.04.007.04

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The new round of power sector reform has promoted the rapid development of China’s electricity direct trading market. This paper reviews the development history, market models and characteristics of the electricity direct trading market in such typical provinces as Yunnan, Inner Mongolia and Guangdong, and summarizes their respective achievements and challenges. Some policy recommendations are proposed on the future construction directions of China’s electricity market, which can provide a reference for electricity market construction of China’s other provinces.

Mechanism Design of on-Grid Electricity Considering Carbon Emissions

LIU Dingyi, YE Ze, ZHANG Xinhua

2017, 50(4):  11-16.  DOI: 10.11930/j.issn.1004-9649.2017.04.011.06

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The existing quantity of on-grid electricity of electricity suppliers is mainly determined according to the proportion of its generation capacity, but the on-grid electricity tariff is the unified benchmark price. Based on the principle of minimum total generation cost under the constraint of carbon emissions, this paper designs the allocation mechanism of on-grid electricity quantity and its tariff mechanism in oligopoly power market, and makes a comparison with the existing on-grid electricity mechanism. The results show that: (1) the new mechanism can encourage electricity suppliers to report their true cost types to ensure the implementation of the minimum total generation cost under the constraint of carbon emissions; (2) compared to the existing mechanisms, the new mechanism can help to reduce carbon dioxide emissions, and save the total generation cost at the same level of carbon emissions;(3) the new mechanism gives priority to low-emission electricity suppliers, which can help to make the high-emission units gradually exit the market.

Key Issues for Orderly Operation of China’s New Electricity Market Reform Pilot

MA Li, HUANG Liming, XUE Song, FAN Menghua, ZHANG Xiaoxuan

2017, 50(4):  17-22.  DOI: 10.11930/j.issn.1004-9649.2017.04.017.06

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A systematic study is made on the key issues for orderly operation of China’s new electricity market reform pilot, and the top strategic design for pilot is proposed. The order operation system for China’s new electricity market reform pilot includes such market rules as market access requirements and trading varieties. A system is established for assessing the effectiveness of pilot dividend and risk. Finally, some solution measures are proposed to such problems arising in the process of pilot as market power and transmission congestion. The study results can provide a reference for formulating implementation schemes and detailed rules of reform pilot, guarantee continuous release of reform dividend in the process of pilot, and accumulate experience for establishing a unified, open, competitive and orderly national electricity market in the future.

International Experience and Enlightenment of Regulatory Investment in Pre-pricing of Transmission and Distribution

LI Chengren, GAO Xiao, YOU Peipei, BU Yinhe

2017, 50(4):  23-27.  DOI: 10.11930/j.issn.1004-9649.2017.04.023.05

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It is necessary to establish a standardized investment review system for setting up a regulatory mechanism of pre-pricing investment review. And the core of the system is to set up the basis and method for scientific investment review, the incentive mechanism for investment cost saving and adjustment mechanism for investment deviation. The paper studies the problems in China in power grid investment regulatory policies and the international experience of investment review in such countries as Britain, Australia and the United States. Some reflections are proposed based on the existing reform conditions in China, such as continuous improvement of the regulatory investment policies through practice and establishment of a complete investment audit system, objective and fair regulatory policies, and practical and effective regulatory methods.

Clean Energy Generation and Dispatch in Reformed Wholesale Electricity Markets:Experience in the United States

David Hurlbut, MA Li, Ella Chou, ZHANG Fan, FAN Menghua, LI Jing, QU Haoyuan

2017, 50(4):  28-34.  DOI: 10.11930/j.issn.1004-9649.2017.04.028.07

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In recent years, the US electricity market has undergone several stages of reform, and gradually formed the market where the wholesale electricity price is determined by the supply and demand. The US electricity market also changes along with the rapid development of clean energy, forming a number of the market mechanisms that is specifically developed for clean energy power generation characteristics. On the basis of discussing the pricing mechanism of US electricity market, this paper analyzes the experience and practice of encouraging renewable energy development policy and clean energy dispatch from the angle of market mechanism and dispatching decision, and puts forward the reference for clean energy dispatching in China.

2016 Annual Report on Power Trading

HU Weidong, GU Yugui, XU Liang, LI Zengbin

2017, 50(4):  35-38.  DOI: 10.11930/j.issn.1004-9649.2017.04.035.04

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In order to standardize the electricity transaction data and analyze the problems existing in current electricity trading, the electricity transaction data of 2016 are published and an analysis is made of the electricity transaction quantity and the developing tendency of electricity market trading, cleaning energy consumption and direct transaction in recent years. It is pointed out that despite of the rapid increase of market trading electricity in 2016, a lot of problems exist in the operation of electricity trading, such as inadequate market mechanism, difficult clean energy consumption and irregular direct transaction. Some suggestions are proposed to enlarge market electricity trading, including accelerating promulgation of power trading rules, innovating trading varieties, strengthening the construction of market entity credit system, and regulating direct electricity transaction.

Research and Application of Trans-Province Trading Modes of Renewable Energy

LI Guodong, LI Gengyin, YAN Yu, ZHOU Ming, PANG Bo, LI Zhu

2017, 50(4):  39-44.  DOI: 10.11930/j.issn.1004-9649.2017.04.039.06

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Wind power and solar energy have big potential and mature technical conditions for development, and their development has become an important direction for the world’s power development. However, the consumption problems of the renewable energy are also becoming increasingly prominent. The paper introduces the status quo of China’s renewable energy consumption and analyzes its principal problems, including unreasonable planning, incompatible power market mechanism, limited trans-province transmission capacities, and incompatibility between power sources structure and renewable energy consumption. A study is carried out on improving the trans-province capacities for renewable energy consumption, and it is proposed from the angle of electricity trading to establish a new mechanism for increasing interprovincial renewable energy replacement, opening the direct trading between electricity users and renewable energy suppliers, establishing short-term interprovincial trading and trans-region ancillary services compensation of renewable energy. An analysis is made of the application prospect of proposed mechanism in China. In the end, the paper introduces the practical application of some trans-province trading mode in some provinces, which fully proves the effectiveness of above mentioned measures in enhancing trans-region consumption capacities in China.

Research on Cooperative Game of Electricity Providers under the Market Environment

TAN Zhongfu, WANG Guan, LI Peng, YU Xiaobao, LI Qiuyan, WANG Lili

2017, 50(4):  45-51.  DOI: 10.11930/j.issn.1004-9649.2017.04.045.07

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With the open of electricity sales business, electricity sales market is gradually forming, and more and more electricity sales companies are being established as a result of the entry of social capital. A study is made on the market cooperation between electricity suppliers in the early stage of electricity market. By introducing the game theory, a game model of the market behavior of electricity suppliers is constructed under different scenarios to explore the cooperation feasibility between different electricity suppliers. The simulation results show that electricity suppliers can increase their profits through cooperation, and the greater the electricity forecasting deviation is, the higher the sensitivity of the unit transaction cost is.

Power System

Node Ordering in Power Flow Calculation Based on Graph Partitioning Algorithm

TANG Can, GUO Rui, GU Liqiang, DONG Shufeng

2017, 50(4):  52-58.  DOI: 10.11930/j.issn.1004-9649.2017.04.052.07

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With the development of society, the topology of power grid is becoming more and more complex, and the dimension of power flow calculation is growing accordingly. Against this background, appropriate node ordering is needed to effectively accelerate the power flow calculation. As a scale-free network, the power system network can be abstracted into a graph to represent the topological relations between the various nodes. To solve the problem of node ordering, this paper presents a method based on dissection ordering algorithms to optimize node number, which can accelerate the speed of node ordering and power flow calculation of large scale system. Based on an example of IEEE 14-bus system, the process of the proposed method is described. The simulation results show that the speed and effectiveness of the proposed algorithm can satisfy online computing requirements.

Probabilistic Harmonic Power Flow Based on Latin Hypercube Sampling Applied to Different Random Variable for Active Distribution Network

YANG Wenhai, HUANG Lingyu, CHENG Huaxin, LI Ruihuan, WANG Jingmin

2017, 50(4):  59-65.  DOI: 10.11930/j.issn.1004-9649.2017.04.059.07

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With the increase of large amount of distributed generations connecting to power grid, it is inevitable that a lot of harmonic waves would be brought to the active distribution network, and it is of great significance to study characteristic of the harmonic spectrum and its distribution in active distribution network. A probabilistic power flow based on improved Latin hypercube sampling for active distribution network is created. The loop-analysis-based power flow algorithm is introduced for weakly meshed distribution network while a strict method to process PV nodes is also proposed. On that basis, with regard to independent random variables, dependent random variables and discrete data, an improved Latin hypercube sampling is proposed to describe uncertainty of harmonic spectrum. Various numerical test results on a 14-bus distribution network demonstrate validity of the proposed method.

Low-Carbon Active Distribution Network Planning based on Two Bionic Algorithms

LI Yujia, DONG Chuan

2017, 50(4):  66-70.  DOI: 10.11930/j.issn.1004-9649.2017.04.066.05

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Distributed generation(DG) brings many new challenges to future distribution network planning. Based on the traditional distribution network planning, a new planning is made for active distribution networks with related standards taken into account. In the process of network planning, the power grids that are in operation and the output of distributed generation are selected as optimization variables while the environmental cost caused by power network carbon emission is set as evaluation criteria. By taking the 14-bus system as an example, the genetic algorithm (GA) and cuckoo search (CS) algorithm are combined and improved according to the actual situation of power network. Finally, in the MATLAB environment, the MATPOWER is used as a flow calculation tool to achieve the low-carbon planning of active distribution network. The results of case study show that the proposed planning method is simple and effective, which can provide a reference to the active distribution network planning for low-carbon economy.

Contingency Screening and Ranking for Voltage Stability Based on Grey Correlation Analysis Method

DANG Jie, ZHANG Wenchao, WANG Shaobo, XI Jianghui, XU Youping, LU Yong, GU Xueping, PAN Yan

2017, 50(4):  71-76.  DOI: 10.11930/j.issn.1004-9649.2017.04.071.06

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Contingency screening and ranking is an important part of power system voltage stability assessment. In view of the unicity of the existing power flow-based contingency screening method, a new contingency screening and ranking method is proposed in this paper. Firstly, a contingency screening index system is built by considering the characteristics of induction motor, load capacity, power support and transmission lines. Secondly, in view of the limits of single index in reflecting the severity of contingency, the grey correlation analysis method is used to obtain the integrated index and to assess severity of contingency by integrating multiple factors. The proposed method is verified through the data of an actual power network which has voltage stability problems. The result shows that the voltage stability contingency screening and ranking method based on grey correlation analysis is reasonable and effective.

Research and Analysis of Electrode Line Breakage Fault of Yibin ±800 kV Converter Station

ZHANG Liuchun, KANG Peng, ZHANG Cuixia

2017, 50(4):  77-80.  DOI: 10.11930/j.issn.1004-9649.2017.04.077.04

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After fault occurred on ±800 kV DC wall bushing of pole II in Jinhua converter station, the grounding line also has breakage fault. By using ATP-EMTP, response of grounding electrode conductor and shielding wire is simulated with 5 970 A and 5 215 A fault current. The results are compared with recorded fault waveform. According to calculation results, the breakage reasons of insulator string and shielding wire are analyzed in detail. The recommended grounding line insulation configuration is also introduced.

Real Power Flow Tracing Optimal Modeling and Its Application

HONG Shaoyun, CHENG Haozhong, HUANG Lina, JIN Yanming, LIU Lu

2017, 50(4):  81-86.  DOI: 10.11930/j.issn.1004-9649.2017.04.081.06

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Conventional power flow tracing uses proportional sharing assumption in calculating nodal sharing, and its models are generally algebra equations. In order to promote the application of power flow tracing, a real power flow tracing optimal modeling is established in this paper based on a real power network flow. This model establishes attributive constrains and decision-making objectives from mathematical optimization perspective. The attributive constrains make the power flow tracing satisfy the real power balance of network, and the decision-making objective can be established according to the real application. The method for establishing the decision-making objective is demonstrated through two application examples, including load nodal power price and power price competitions. When applied to calculation of load nodal power price, the model can better reflect the fair sharing principles of transmission networks. When applied to calculation of power price competitions, the model can give the maximum and minimum power price competition result of power flow tracing.

Research on Energy-Saving Reform Decision-Making of Medium-Voltage Distribution Lines Considering Line Loss Evaluation Index

PENG Xiangang, LIN Zhuoqiong, LIU Yi

2017, 50(4):  87-93.  DOI: 10.11930/j.issn.1004-9649.2017.04.087.07

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Reformation of distribution lines is one of the core tasks of energy planning. However, power supply departments are prone to focus only on aspect of problem in practical work and failed to achieve global optimization. A new decision method of medium-voltage distribution lines reform is proposed with consideration of line loss evaluation index. The line loss evaluation system including line structure, technical equipment and line economic operation indicator is developed based on comprehensive weights and fuzzy theory. In view of main factors influencing assessment, a fuzzy evaluation matrix is established through the up half trapezoidal membership function. Meanwhile, an integrated weight is derived by combing interval analytic hierarchy process and effect risk entropy-weight. Proposed route is assessed by using five kinds of evaluation methods for emergency order. Finally the established model is applied to line loss evaluation of medium voltage distribution power system, which could be the guidance for energy saving reconstruction and loss reduction.

Research on Polyester Fiber for Low Frequency Sound Absorption

ZHANG Bin, PEI Chunming, ZHANG Jiangong, ZHOU Bing

2017, 50(4):  94-99.  DOI: 10.11930/j.issn.1004-9649.2017.04.094.06

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In view of the problems of low frequency noises in substation, the polyester fiber impedance tube is chosen to study the low frequency sound absorption properties of polyester fiber. The influences of bulk density, material thickness, air cavity on the low frequency sound absorption properties are discussed with composite structure of polyester fiber and Helmholtz resonator. The results show that the bulk density of polyester fiber has an optimum range for sound absorption performance. The low frequency sound absorption coefficient of polyester can be improved by increasing the thickness of both the polyester fiber and air cavity while it is still low at 100 Hz; The sound absorption coefficient of composite structure of polyester fiber and Helmholtz resonator can reach up to 0.9 at 100 Hz while their average sound absorption coefficient is also high.

Power Plants

Parameter Estimation Method for Torsional Vibration Model of Turbine-Generator Shafts

JIN Tiezheng, ZHANG Lei, XU Yatao, ZHANG Junjie, CUI Yahui, GU Yujiong

2017, 50(4):  100-105.  DOI: 10.11930/j.issn.1004-9649.2017.04.100.06

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The precision of the torsional stress analysis for torsional vibration online monitoring and protection depends on the similarity of the inherent torsional vibration characteristics between the torsional vibration model and the actual turbine-generator shafts. However, errors are often produced in the stiffness parameters during the modeling process, which affects the precision of the torsional vibration analysis. In order to estimate the stiffness parameters of the model and eliminate the error of the inherent torsional vibration characteristics, a parameter estimation method for obtaining the adjustment of the stiffness parameters is proposed by establishing the relational equation between the micro-increment of the stiffness parameters and the changes of the inherent characteristics. Through repeated iteration, the inherent characteristics of the adjusted model can be very close to the torsional vibration test results, and thus ensures the precision of the torsional vibration stress analysis.

Research and Optimization on Primary Frequency Regulation Characteristics with Large Frequency Deviation for Coal-Fired Power Plants

GUI Yishu, SHEN Congqi, CHEN Huanle, CHENG Jiyun, WANG Nianlong, TANG Longsheng, LIU Gang, CHEN Yuanliang

2017, 50(4):  106-112.  DOI: 10.11930/j.issn.1004-9649.2017.04.106.07

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Through the analysis on two DC power transmission line faults, it is discovered that the characteristics of the dynamic response of coal-fired power plants to primary frequency regulation are generally poor, and the dynamic characteristics of large frequency deviation are completely different from those of small or medium frequency deviation of the power grid. Based on the identification of large frequency deviation model, the primary frequency regulation strategy is optimized, and the experiments of large frequency deviation are conducted with the results being analyzed to estimate the risks of the loading conditions and evaluate the performance of the primary frequency regulation with large frequency deviation for coal-fired power plants so as to effectively improve the primary frequency regulation performance on the premise of ensuring the unit safe operation, which benefits both the power grid and the generating units.

Study on Optimization of Lubricating Oil System of 1 000-MW Ultra Supercritical Steam Turbines

YE Pengzhen, LIU Changsheng, LI Jianhe, WANG Guangling, HONG Jianhua

2017, 50(4):  113-117.  DOI: 10.11930/j.issn.1004-9649.2017.04.113.05

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The lubricating oil system of the turbine generator unit relies on the DC oil pump significantly in case of turbine unit accidents, if it is not equipped with an independent main oil pump and its electrical connection is weak Once an abnormal event occurs, the DC oil pump cannot be started in time, which will directly lead to the severe accidents of steam turbine shaft break and bearing pad overheated damage. Based on the comparative analysis of the pump starting up test, the upgrade on the electrical and interlock circuit of the lubricating oil system is carried out. Thus the potential risks in the DC oil pump starting process are solved, and the risks of shaft break and bearing pad overheating are lowered. The study results are helpful for the steam turbines of the same type.

Research and Application of the Automatic Determination of ppb-Level Total Iron in Water-Steam System of Power Plants

XING Chengxia, WANG Yinggao, LIU Liya, WANG Dan

2017, 50(4):  118-122.  DOI: 10.11930/j.issn.1004-9649.2017.04.118.05

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It is of great importance to quickly determine the trace total iron in the water-steam system to figure out the corrosion status of the thermal system in a timely manner. Unfortunately the procedures of conventional method are too complicated and inconvenient to perform field testing. The flow injection analysis (FIA)-TPTZ spectrophotometry is proposed in this paper as a quicker and simpler way to determine the trace total iron in the water. In order to further improve this method to detect the trace total iron below the lower limit, the in-depth study is carried out on the major factors affecting the sensitivities, such as the reagent and carrier pump speeds, the colour coil length and the pH values of buffer solution and samples. After such improvements, in the range of 0.5~100 μg/L, the liner regression coefficient is now above 0.999, the RSD less than 1.0%, and the detection limit is extended down to 0.5 μg/L from previous 22.7 μg/L, with the detection rate at 60 samples per hour. The relative error is less than 10% in comparison with the current standard method. Therefore, it is suitable for automatic detection of trace iron and easy to be applied for on-line monitoring.

The Starting up and Operation of Condensate Polishing Treatment System for Hongyanhe Nuclear Power Plant

ZHOU Guangji, XU Yan, ZHANG Lanhe

2017, 50(4):  123-129.  DOI: 10.11930/j.issn.1004-9649.2017.04.123.07

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The condensate polishing treatment system(ATE) and its good operating condition are vital to the operation security of nuclear power plants. Take the ATE system of the Unit 3 and 4 of Hongyanhe Nuclear Power Plant as the study case, the authors compare the ATE effluent concentration and water production under the scenario of the first-time start-up versus the normal start-up, then present the complete separation method using mixed bed resin, and put forward the major control processes of resin regeneration. Problems which occurred during commissioning are also analyzed and corresponding preventative measures are provided. After commissioning, the ATE systems of Hongyanhe Nuclear Power Plant Units 3 and 4 have been maintained in good operating condition. The ATE effluent hydrogen conductivity, Na⁺ mass concentration and SiO₂ mass concentration are respectively 0.08 μs/cm, 0.10 μg/L and 1.91 μg/L. And the water volume of cation bed and mixed bed are 1.2×10⁵ tons and 4.4×10⁵ tons respectively. The resin separation and regeneration performance is satisfactory with the volume fraction of the anion resin in the cation resin layer less than 0.08% and the volume fraction of the cationic resin in the anion resin layer less than 0.07%. During the operation process of ATE system, the concentrations of Na⁺, Cl^- and SO₄^2- in the steam generator sewage water have all met the requirements in the water chemistry specifications.

Detection of Chlorine Content in Phosphate Ester Fire-Resistant Fluids Using Energy Dispersive X-ray Fluorescence Spectrometry Method

MING Julan, LI Haiyan, YU Lujing, ZHOU Feimei, PAN Zhiying, SHEN Xiaoming

2017, 50(4):  130-134.  DOI: 10.11930/j.issn.1004-9649.2017.04.130.05

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For the sake of secure operation, it is of great importance for the power plant to detect chlorine content in the phosphate ester fire-resistant fluids in an accurate and efficient way. In this paper, in order to establish the industry standard called “Detection of Chlorine Content in the Phosphate Ester Fire-Resistant Fluids using Energy Dispersive X-ray Fluorescence Spectrometry Method”, the basic principles, operating conditions and testing methodology are studied. Furthermore, to evaluate the accuracy of the method, five samples are tested collaboratively in seven laboratories. The results show that the water and oil contents have no effects on the results while the helium atmosphere is beneficial for the measurement of chlorine content in the phosphate ester fire-resistant fluids. In terms of repeatability and reproducibility, detection limit, recovery rate and accuracy, the energy dispersive X-ray fluorescence spectrometry testing method for chlorine content in the phosphate ester fire-resistant fluids exhibits high precision and efficiency, and thus can be put into practice in the field of power industry.

Light-Scattering-Based Online Monitoring on Governor Oil Particle Size for Power Plants

HU Bian, WAN Yuan, TANG Wei, SU Mingxu

2017, 50(4):  135-140.  DOI: 10.11930/j.issn.1004-9649.2017.04.135.06

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With the construction of intelligent power plant, the unit condition monitoring is getting more important. By adopting the light scattering mechanism, the particle size analyzer is developed independently in the laboratory and gets calibrated and verified. After it is applied in the governor oil system of Hongjiang Hydropower Plant Unit 2, a potential of oil pollution is discovered, indicating that the monitoring data can reflect the operating conditions of the unit. Through comparison, it is concluded that the analyzer online monitoring results are consistent with those of the particle counters of HACH 8011+ and PAMAS SBSS, which proves that the light scattering method is highly accurate and suitable for online monitoring the turbine oil particle sizes and can provide a support for the change of condition maintenance from planned maintenance. The analyzer developed also has the characteristics of low cost and good stabilities.

Condition Assessment and Residual Life Prediction for Gearbox Bearing of Wind Turbine

ZHAO Hongshan, ZHANG Jianping, GAO Duo, LI Lang

2017, 50(4):  141-145.  DOI: 10.11930/j.issn.1004-9649.2017.04.141.05

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In order to improve reliability and economy of wind turbine, a method based on Markov chain is proposed. It is used for assessing operating condition and predicting residual life of gearbox bearing of wind turbine. Firstly, the degradation process of bearing wear status is described by Gamma distribution whose parameters can be estimated by using maximum likelihood estimation method. Secondly, the wear status of gearbox bearing are divided into four levels, and the corresponding upper and lower bounds of each level are also determined. Then, state transition probabilities are calculated to construct the state transition matrix. Finally, the proposed method is applied in simulation of wind turbine gearbox bearing. The simulation result verifies the effectiveness of presented method in determining the wear state and residual life of gearbox bearing of wind turbine.

Study on the Impact of Reclaimed Water Reuse on Ultrafiltration System Operation

JIA Jianbo

2017, 50(4):  146-149.  DOI: 10.11930/j.issn.1004-9649.2017.04.146.04

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The influent water of the ultrafiltration (UF) system in a power plant has been changed from tap water to reclaimed water to realize the recycling and comprehensive utilization of reclaimed water. The changes of the key performance indicators of the UF system during the water source switching period are studied in this work. It is found that the change of reclaimed water has less effect on the influent and product water turbidity, while the operation mode of the UF system has a significant impact on the influent and product water turbidity. In comparison with that in continous operation, the influent turbidity is increased by 162.5% and the product water turbidity keeps unchanged when the UF system is in intermittent operation. In addition, there is a good linear relationship between the filtration efficiency and the influent water turbidity of the UF system, that is, the greater the influent turbidity is, the higher the filtration efficiency will be. After the reclaimed water is used, the trans-membrane pressure drop of the UF system is increased by 30%. The comprehensive analysis on the routine operation data of the UF system shows that the discontinuous operation and the influent water quality deterioration are the main reasons for the trans-membrane pressure drop increase of the UF system.

Energy Conservation and Environmental Protection

Research on and Application of Comprehensive Ultra-Low Emission and Deep Energy Saving Technologies in a Coal-Fired Power Plant

WU Laigui, LIU Yuhai, XU Qingguo, LIU Xiaodong, LIANG Chengwu, MEI Kui, LIU Riwei, SHEN Jian, YONG Guosong

2017, 50(4):  150-156.  DOI: 10.11930/j.issn.1004-9649.2017.04.150.07

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In order to realize ultra-low emission and deep energy saving, a power plant is taken as an exampleto study and analyze a comprehensive technical route of ultra-low emission and deep energy-saving of the flue gas by using the system synergistic treatment method. The technical schemes, such as low-NO_x burner retrofit in the boiler, low-low temperature and pulsed power supply synergistic effect-raising for the electrostatic precipitator(ESP), ESP steam heating and hot air blowing, desulfurization tray and interactive spray synergistic effect-raising, wet ESP utilization and zero waste water discharge and MGGH and condensate water heater coupling energy-saving, are put forward. The study results show that the effect of the ultra-low emission retrofit with these technologies is better than the national ultra-low emission limit requirements, and at the same time the energy consumption of the units is reduced, the the flue gas waste heat is recycled and the adaptability of the units to coal types is improved. The study result may provide reference for similar projects.

Analysis on Operating Status of SCR Facilities in Active Coal-Fired Units

FENG Qianwei, ZHANG Yang, WANG Fengji, ZHU Yue

2017, 50(4):  157-161.  DOI: 10.11930/j.issn.1004-9649.2017.04.157.05

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In order to provide helpful reference for flue gas ultra-low emission retrofits, current operating status of the SCR flue gas denitration system are analyzed which have been installed on 61 generation units in 26 power plants. A variety of practical data are obtained including the denitration efficiency, inlet and outlet NO_x concentrations, ammonia molar ratio, SO₂/SO₃ conversion rate, ammonia escape rate, running flue gas temperature, system resistance, temperature drop, etc. Also the major functionalities of the SCR denitration system are acknowledged. From the study results the overall performance is satisfactory for most of the denitration systems. However there still exist some problems as follows. The SCR system inlet NO_x concentration deviates significantly from the original designed value due to the factors such as the furnace type, coal quality, combustion condition and design margin. The improper ammonia injection causes higher-than-normal ammonia molar ratio and consequentially the ammonia escape concentration exceeding the related standard. Low SCR system inlet flue gas temperature at low loadings and large system temperature drops are also noticed in some units. Therefore, suggestions and advice are put forward accordingly.

Experimental Study on Mercury Removal Effect and Mercury Emission Characteristics of Pollution Control Equipment in Coal-Fired Power Plants

LIU Fasheng, XIA Yongjun, XU Rui, WU Ying, WANG Qian, GUI Liangming

2017, 50(4):  162-166.  DOI: 10.11930/j.issn.1004-9649.2017.04.162.05

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In order to better understand the mechanism of mercury emission from coal-fired power plants and the effects of existing pollution control equipment on synergistic mercury removal, the test study on the mercury emission from four thermal power units in Jiangxi Province is carried out by using Ontario Hydro Method, thus the current mercury emission characteristics of power plants are obtained. The results show that the mercury removal efficiency of the units without mercury oxidant is between 69.01% and 75.63%, while that with mercury oxidant can reach as high as 89.69%. The SCR denitration does not seem to take significant impact on total mercury reduction. However it can promote the oxidation of Hg⁰ to Hg²⁺ and Hg_p. The oxidation ratio of Hg⁰ to Hg²⁺ can be increased drastically with the mercury oxidants being put into use. The electro-static precipitator(ESP) can remove almost all Hg_p, and its average total synergistic mercury removal efficiency is 24.37%. The removal efficiency of Hg²⁺ by wet flue gas desulphurization (WFGD) is 88.39%. After processed through SCR, ESP and WFGD, the mass concentration of mercury in the exhaust gas is limited within the range between 3.91 and 8.89 μg/m³, which is far below what is specified in the national emission standard.

Optimization and Adjustment of Ammonia Injection System and Improvement of Flue Gas Sampling Method for SCR Denitrification System of Thermal Power Plants

MAO Yisheng, WU Zhipeng, ZHANG Xiaotian

2017, 50(4):  167-171.  DOI: 10.11930/j.issn.1004-9649.2017.04.167.05

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Constrained by the boiler layout, the compact installation of the denitrification system causes the flue gas concentration field unevenly distributed. As a result, some problems such as incomplete catalytic reduction reaction and unrepresentative sampling of outlet flue gas have commonly existed. In this paper, through the analysis on the measurement of SCR outlet NO_x distribution, the ammonia concentration in the SCR reaction area is improved by using the ammonia injection valve to adjust the ammonia injection volume. In this way, the unevenness degree of NO_x density concentration at the Outlets A and B is decreased to 20% and the utilization ratio of the catalyst is enhanced. By taking advantage of gaseous pollutants sampling method and uniform ventilation design method, the SCR outlet gas sampling method is improved and the uniform NO_x sampling is achieved, which effectively lowers the measurement deviation between the outlets of SCR and flue gas discharge systems. The ratio of NO_x concentration at the two outlets is reduced from 1.42 to 0.98. The study results can ensure stable ammonia injection volume control.

Information and Communication

Estimation Model Simulation on the Loss-Reduction Effect of Smart Grid Based on Big Data Analysis

LV Shouxu

2017, 50(4):  172-175.  DOI: 10.11930/j.issn.1004-9649.2017.04.172.04

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In view of the large dynamic estimation error of loss-reduction effect of smart grid, a smart grid loss-reduction estimation model is proposed in this paper based on big data analysis, which applies the Map/Reduce model to process the big data of smart grid. According to the statistic and analytical results, the smart grid can be divided into different subnets, and different load forecasting models are applied to predict the loads of subnets. The estimated overall load of smart grid is corrected through fussing the predicted loads of subnets. By inputting the load predictions into the smart grid loss probability evaluation model, the smart grid loss-reduction analysis can be realized under the restriction of both single and combined factors, and a dynamic assessment can be made on the loss-reduction effect of the smart grid. The experimental results show that the proposed model is very effective for estimating the loads of smart grid on both weekdays and playdays.

Key Link and Technology of Secondary Information Standardization Platform of Smart Substation

LIU Qingquan, HAO Xiaoguang, HE Lei

2017, 50(4):  176-180.  DOI: 10.11930/j.issn.1004-9649.2017.04.176.05

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Due to management and technology irregularity, a series of problems exist in current smart substation construction, such as wrong configuration file and frequent requirement changes. Starting from secondary substation information system, the entire process of substation construction is analyzed in detail. A standardized platform for smart substation secondary system information is proposed, which analyzed every key link of the construction. The key technologies including ICD file detection and SCD file version control are also described. The platform standardizes substation secondary system and coordinates engineering construction. The proposed platform is applied in the whole construction process of pilot 500 kV Baodong project. The construction result demonstrates effectiveness and usefulness of proposed platform.

Study on the Method of Power Network Operation Early Warning Using Remote Sensor Monitoring and Locating of Satellites Based on Power Grid GIS

SUN Shijun, ZHANG Zhiqu, HAN Hong

2017, 50(4):  181-184.  DOI: 10.11930/j.issn.1004-9649.2017.04.181.04

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With rapid development of smart grid construction, the power grid forest fire monitoring and early warning capability becomes more and more important. Combined with polar orbiting satellite remote sensing fire point data, weather monitoring and forecasting data, grid geographic information and emergency resource data, power facilities which would be most heavily affected by the fires are analyzed. Based on meteorological monitoring and forecasting, fire trend is forecasted via professional standardized sign language and early warning strategies is established. Through research and development of early warning and release technology, the fire point, weather environment, affecting equipment, disposal strategies can be distributed to relevant staff. The ability of power grid disaster prevention, comprehensive monitoring and emergency response decision making is improved by using proposed method.