Table of Content

20 May 2017, Volume 50 Issue 5

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Security Column

Study on Fast Assessment of Shafting Fatigue Damage Based on Turbo-Generator Torque

LU Luyi, WANG Kun, LI Wangfan, SUN Qing, XUE Chenyong

2017, 50(5):  1-6.  DOI: 10.11930/j.issn.1004-9649.2017.05.001.06

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Based on the full-scale model analysis coupled with the basic torsional vibration analysis, a method to assess the shafting torsional vibration fatigue damage is proposed and validated by using the transient numerical analysis. The method can evaluate the damage directly by using the generator’s electromagnetic torque instead of the speed measurement gear and the torsional vibration sensor. The results are consistent with those evaluated by the method adopting turbine-end torsion angle data. This method can improve the precision and accuracy of the torsional vibration fatigue damage assessment.

Study on the Cause of High-Temperature Corrosion of Water Wall Tubes in a 660-MW Supercritical Opposed Firing Boiler

LIU Xinchang, YAN Xiaozhong, JING Pei, LI Pei, ZHANG Yiman, WU Aijun, CHEN Shaolong

2017, 50(5):  7-12.  DOI: 10.11930/j.issn.1004-9649.2017.05.007.06

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In order to explore the causes and the mechanism of frequent high-temperature corrosion in the supercritical opposed firing boilers, the cause analysis is carried out for a 600-MW boiler through the coal quality analysis, the waterwall thickness measurement, the waterwall surrounding atmosphere testing, and the corrosion products analysis by using SEM, EDS and XRD. The study results show that the waterwall high-temperature corrosion occurs mainly in the high-temperature load areas of the burners at all levels on both sides and spreads unevenly. The unevenness is attributed to the high-temperature sulfurization and oxidation caused by the sulfide and the oxygen in the combustion. In addition, the reducing atmosphere formed in the lower part of the furnace leads to the increase of the H₂S concentration making the high-temperature corrosion at this part worse.

Accurate Diagnosis of Abnormal Vibration of High-Medium Pressure Rotor in a 300-MW Unit

ZHANG Xueyan, LI Shuwei, LIU An

2017, 50(5):  13-19.  DOI: 10.11930/j.issn.1004-9649.2017.05.013.07

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Aiming at the problem of vibration climbing of the high-medium pressure rotor during the operation of a 300-MW unit, this paper analyzes the abnormal situations such as the differences in vibration characteristics of the rotor between cold and hot(warm) states and the decrease in rotor bending and concludes that the vibration problems are caused by the cracks in the rotor, which lead to the decrease of the rotor stiffness in the hot state and the damage of the rotor balance. The rotor detection shows that there are severe cracks in the rotor shaft. The detection confirms the accuracy of the diagnosis. The timely shutdown and maintenance as well as the detection of the existence of the cracks, have prevented the unit from potential shaft break and collapse. Moreover, the producing process of the rotor cracks and the possible impacts of in-depth peaking load and flexible operation of thermal power units on the rotor safety are also studied in this paper.

Key Technologies and Their Applications of Power Units False Alarm Diagnosis in Integrated Smart Alarm

NING Jian, ZHANG Yong, ZHANG Zhe, WANG Yaoxin

2017, 50(5):  20-25.  DOI: 10.11930/j.issn.1004-9649.2017.05.020.06

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The integrated smart alarm is one of the core functions of real-time monitoring and early warning applications in the smart grid dispatching and control system. Aimed at the false alarm caused by integrated smart alarm which cannot effectively distinguish the tripping and manual halt of power units, and based on an analysis of the application of the integrated smart alarm in north China grid and an on-site investigations into some plants, a real-time acquisition technology of manual halt signals of coal-fired and pump storage units is proposed innovatively and the optimized false alarm diagnosis logic of power units is presented based on steady and dynamic(PMU) data. The technology is implemented in the operating system of North China grid and effectively decreased the false alarms. The result proves the reliability of the technology in addressing the false alarm problems.

Impact of Multi-HVDC Commutation Failure on Weak AC Section and Its Countermeasures

HU Xiaofei, CHEN Dezhi, ZHANG Yin, TANG Wei, YANG Cheng, WANG Jingjing, YUAN Sen

2017, 50(5):  26-32.  DOI: 10.11930/j.issn.1004-9649.2017.05.026.07

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The transient imbalance energy accumulated by Multi-infeed HVDC (MIDC) commutation failure has impact on weak AC section and threaten power grid safety. It is necessary to study its characteristics and precautionary measures. In this paper, based on the typical grid structure in China, the impact characteristics of MIDC commutation failure on the weak AC section are simulated and analyzed with the characteristics of power fluctuation, continuity and simultaneity. From the view of safety control and planning, a series of countermeasures are put forward, such as pre-control measures of weak AC section and MIDC power, emergency control measures of taking initiative to HVDC pole blocking after a certain number of commutation failures and grid strengthening measures at weak AC cross-section. Simulation results verify validity of analysis and effectiveness of proposed measures. Research conclusions can provide reference for the actual operation of interconnected power network.

Analysis and Treatment of Abnormal AGC Orders Caused by a UHVDC Block Fault

SUN Wenduo, LU Min, XIANG Zhongming, NI Qiulong, LIU Junwei, GAO Qiang, JIN Xiaohu

2017, 50(5):  33-38.  DOI: 10.11930/j.issn.1004-9649.2017.05.033.06

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Based on analysis of AGC orders and feedback data during an UHVDC block fault accident treatment, abnormal conditions in automatic generation control system are discussed and rectification measures are proposed. Automatic generation control(AGC) strategies in Zhejiang power grid and accident treatment of one ±800 kV Yibin-Jinhua DC unipolar block fault performed by provincial dispatcher are introduced. System defects are found after reviewing data changes. Improvement measures in transmission mechanism of power importing data, control of low frequency and dynamic dead band optimization are proposed. These measures are already operated in actual power grid system operation which have instructive significance for UHVDC export/import power grid.

Research on United Adjustment Power Source System Single Phase Ground Fault Line Selection

WU Pengyue, JIAO Shangbin, ZHAO Feng, KOU Shuichao, SHI Yanjin

2017, 50(5):  39-45.  DOI: 10.11930/j.issn.1004-9649.2017.05.039.07

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The power plant auxiliary machine united adjustment power source system is non-utility frequency and small current grounding system. Conventional protection device cannot detect single phase grounding fault in the system correctly. Operating conditions of united adjustment power source system is analyzed, and minimum capacitive ground fault current value is calculated in single busbar low frequency operating condition. Based on calculation, technical requirements of non-utility frequency low current grounding fault line selection device is proposed. Then a high precision fault line selection device which adaptive to system frequency changes is developed. A special functionality simulation test circuit is also built to test developed device. The testing results show that proposed device satisfies design requirements, works well after commissioning and solves practical engineering problem.

Principle and Implementation of Adaptive Neutral Line Breaking Protection

CHEN Qianshen, LIU Chunfang, LIAO Weiwen, CHEN Yuan

2017, 50(5):  46-51.  DOI: 10.11930/j.issn.1004-9649.2017.05.046.06

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Neutral line breaking protection mainly uses load voltage and neutral point displacement voltage. The protection setting value needs to greater then maximum load voltage during normal operation, which leads to low protection sensitivity in long and imbalanced transmission lines. In order to solve this problem, an adaptive neutral line disconnection protection is presented. By introducing adaptive coefficient, the protection setting value is adjusted adaptively according to load imbalance during normal operation. The proposed method has good breaking effect during normal operation, and improve protection sensitivity during neutral line disconnection. The simulation model established by Matlab verifies feasibility of proposed protection.

The Identification and Diagnosis of Self-Blast Defects of Glass Insulators Based on Multi-Feature Fusion

JIANG Yuntu, HAN Jun, DING Jian, FU Hanning, WANG Yufu, CAO Wei

2017, 50(5):  52-58.  DOI: 10.11930/j.issn.1004-9649.2017.05.052.07

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In order to improve the recognition accuracy of insulators in UAV inspection and effectively reduce the influence of the background texture and illumination, a new insulator recognition method is proposed, which integrates the shape, color and texture of insulators. Aimed at the off-chip defects of glass insulators, a defect-detecting method is presented, which can sense the distance between gravity centers of insulator chips, and has an recognition accuracy of insulators higher than 90%. Based on testing with numerous UVA inspection images of transmission lines, it is proved that the proposed method can effectively recognize the insulators under various complicated background conditions, and detect the off-chip defects of glass insulators.

Comprehensive Analysis on Abnormal Defects of Leakage Current on 1 000 kV UHV Surge Arrester

GAO Ran, SHU Chang, PU Daojie, YIN Jianjun, ZHU Yuchen, HUANG Daojun, WU Dasheng

2017, 50(5):  59-64.  DOI: 10.11930/j.issn.1004-9649.2017.05.059.06

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According to the operation of the high voltage side lightning arrester of main transformer in a 1 000 kV UHV transformer substation, a comprehensive analysis was made on the abnormal leakage current in terms of the radial discharge of arrester porcelain insulator contamination, the interference of surface leakage current, the influence of voltage harmonics and the damp of valve elements. And effective measures were used to diagnose the fault. Finally, corresponding check and return treatment was made according to the diagnosis results, which proves the correctness of the diagnosis. The analysis and diagnosis in this paper can provide a reference for the service of UHV arresters.

Research of Transmission Line Icing Wide-Area Monitoring Based on OPGW

WU Nian, WANG Haitao, ZHANG Zongfeng, GUO Weihong, LU Enze, ZHOU Zandong

2017, 50(5):  65-70.  DOI: 10.11930/j.issn.1004-9649.2017.05.065.06

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Transmission lines are erected on the field, affected by natural disasters in larger range and deeper degree, while the icing disasters caused economic losses particularly severe. Based on the analysis of the existing icing monitoring device, we propose the method of transmission line icing wide-area monitoring based on OPGW. The method is based on the OPGW cable inner optical fiber as sensor and optical fiber Brillouin scattering technique, to analyze the relationship between the ice and the cable temperature variation which combines with the ice cover wide-area monitoring principle model. In this paper, the thermodynamic simulation of the cable temperature changes on the OPGW ice and no ice state is established by using the finite element analysis software. To verify the performance of this method, a field test is carried out on a transmission line tower of the icing experimental base. Results show that, transmission line icing monitoring based on OPGW can accurately locate and identify the ice coating section and not iced section, which can realize icing wide-area monitoring.

Enlightenment on the Security of Cyber Information System Under Smart Grid from Ukraine Blackout

LI Baojie, LIU Yan, LI Hongjie, HE Weisheng, ZENG Xiangfeng, CHEN Shuo

2017, 50(5):  71-77.  DOI: 10.11930/j.issn.1004-9649.2017.05.071.07

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On December 23, 2015 and December 16, 2016, the Ukrainian power grid suffered twice serious power outages originated from the malicious code. The first outage was considered as the first public cyber-attack against grid infrastructures in the world. The blackout process, techniques and effects of the 2015 cyber-attack accident are reproduced in the paper, and a general attack framework is then summarized. Considering the critical threats and challenges faced by the cyber information system of China power grid, this paper proposes some ponders and suggestions based on the overall objective of the preliminary construction of Chinese Smart Grid in 2020. The ponders include raising the attention level of cyber security from information war aspect, reassessing the physical isolation method and coordinating cyber security with information open. The suggestions on construction of a strong cyber information security defense system include conducting effective security exercises, promoting localization of core equipment system and others.

Non-Intrusive Fault Detecting and Locating Method in Low-Voltage Distribution Network

WANG Wei, YU Jiancheng, YAO Cheng, HUO Xianxu, Tian Na, LIU Jianyu, YAO Xun

2017, 50(5):  78-83.  DOI: 10.11930/j.issn.1004-9649.2017.05.078.06

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Non-intrusive load monitoring(NILM) is an advanced measuring technology which does not require intrusive construction into users and complicated communication channel. In this paper, the NILM technology is innovatively applied into short-circuit-fault detection and location. Firstly, based on the results of experimental and theoretical analysis, the criterion and the relevant setting process for short-circuit fault with the breaker protection is proposed. Secondly, the fault location algorithms under NILM architecture are presented, which contains three steps: primary locating method for distribution level, primary locating method for important branch based on power drop model, and accurate location method by reusing sub-metering data. Totally four single-phase short-circuit accidents are detected and located during the experiments, which effectively improves the safety level of power users and reduces the construction cost of monitoring system.

Analysis on Distribution Network Fault Repair Time Based on Statistical Data

LIU Zhuan, GUO Quanhui, LIU Juan, WAN Chang

2017, 50(5):  84-87.  DOI: 10.11930/j.issn.1004-9649.2017.05.084.04

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Analysis of the fault repair efficiency of distribution network can timely reflect the operation and management status of the distribution network. Fault repair time duration is a measure of the fault repair efficiency. According to the fact that the fault repair time of distribution network decreased substantially in a company in 2015, an analysis is made on the fault repair time based on statistical data in terms of monthly trend, regional distribution and fault types by cluster, trend and other analyzing methods, from which the existing problems in the operation and management of distribution network are identified. The results show that the company has several problems such as poor capability in lightning resist of distribution network equipment, weak tower structure of rural power grids, long repair time of low voltage faults and low automation degree of distribution lines. Finally, targeted suggestions are proposed, which may help the company to shorten the fault repair time of distribution network.

New Energy

Fuzzy Comprehensive Assessment of Wind Turbines Status Based on Optimal Weight and Membership Cloud

ZHAO Hongshan, ZHANG Jianping, LI Lang

2017, 50(5):  88-94.  DOI: 10.11930/j.issn.1004-9649.2017.05.088.07

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In order to overcome strong subjectivity of empowerment and membership evaluation of status assessment indices in fuzzy comprehensive assessment(FCA), a FCA wind turbine status assessment algorithm is proposed based on optimal weight and membership cloud. Firstly, status assessment indices system is established based on analytic hierarchy process (AHP). The relative deterioration degree is introduced to normalize assessment indices and divide condition levels. Then, entropy weight method and AHP are used to determine objective and subjective weights respectively to obtain optimal integrated weight by nonlinear programming. Next, by utilizing generation algorithm of normal membership cloud, the memberships of assessment indices are obtained to build evaluation matrix. Finally, comparing of simulation results with other assessment methods validates effectiveness of proposed method.

Recognition Method of Wind Curtailment Data Characteristics

YANG Mao, JIANG Bo

2017, 50(5):  95-100.  DOI: 10.11930/j.issn.1004-9649.2017.05.095.06

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In wind power production, wind power generation is limited by load demand variation. This usually leads to wind curtailment. It is very important to identify wind curtailment data because their existence has huge impact on wind power prediction and wind farm equivalency modeling. Characteristics of normal operation data and wind curtailment data are analyzed and compared. Based on standard wind turbine speed to power transfer curve, concept of viscosity range is proposed according to the mean and standard deviation of normal distribution. A wind curtailment data identification and elimination method is established. The application on one of wind farm in Northeast area validates the effectiveness of proposed method.

Research on Active Power Network Planning Model Based on Wind-Solar Complementation

CUI Yong, YANG Jufang, ZHANG Dong

2017, 50(5):  101-106.  DOI: 10.11930/j.issn.1004-9649.2017.05.101.06

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In view of the problems of capacity ratio, point selection of grid-connection and electricity market interest game, this paper, by taking the system power balance, physical constraints, dynamic reactive power support capability and the frequency and voltage characteristics as constraint conditions, uses the classical Newton-Raphson method and quadratic programming method to develop a multi-objective function which takes into account of power generation cost, grid loss, and the benefit of wind power and PV yield. By taking IEEE30, IEEE57 nodes as an example, the optimization planning scheme of wind-solar complementary is obtained by simulation. The calculation result proves the validity of the proposed model. It is proved that the balance of interests and the maximization of objective function can be achieved in the scenario of grid-connection at the large load node and wind-solar power ratio closing to its unit cost ratio.

Power System

Multi-Objective Stochastic Scheduling Optimization Model for Virtual Power Plant Considering Uncertainty of Wind and Photovoltaic Power

WANG Guan, LI Peng, JIAO Yang, HE Nan, ZHANG Wei, TAN Zhongfu

2017, 50(5):  107-113.  DOI: 10.11930/j.issn.1004-9649.2017.05.107.07

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In order to mitigate wind and photovoltaic power generation uncertainty on stable operation of virtual power plant, a multi- objective stochastic scheduling optimization model with consideration of uncertainty and demand response is proposed with robust stochastic optimization theory. Firstly, wind power, photovoltaic power generation, gas turbine(GT) power generation, energy storage systems (ESS) and demand response are integrated into a virtual power plant. Secondly, maximize operational benefits of virtual power plant and minimize system operating cost and abandoned energy costs are selected as objective functions. Then by application of robust stochastic optimization theory, a virtual power plant (VPP) scheduling optimization model is established. The proposed method is applied to distributed power demonstration project in Yunnan, China as an example. The results show that the proposed model can reduce system power shortage penalty cost. The introduction of dual Robust coefficients can provide flexible VPP scheduling decision tools for different risk attitudes of decision makers and respond to wind power and photovoltaic power generation stochastic characteristics effectively. ESS can replace GT unit to provide backup services for wind power and photovoltaic power generation because of its charge and discharge characteristics. It can also smooth VPP output power curve and promote grid connection between wind power and photovoltaic power generation. Demand response is incorporate into VPP to realize power generation side and power side linkage optimization, smooth electric load curve and improve overall operational effectiveness.

Saturated Electricity Demand Forecast Based on Amended Self-Adaptive Logistic Model

YANG Taihua, CHEN Yin

2017, 50(5):  114-120.  DOI: 10.11930/j.issn.1004-9649.2017.05.114.07

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Saturated electricity demand is a pivotal index in power grid development. It is of great significance for power system planning to research on saturation trend and to forecast electricity demand saturation time and scale. Firstly, process of electricity demand growth is divided into three stages. Secondly, an amended self-adaptive Logistic model is proposed. Finally, with the application results to electricity demand in East China, the accuracy and practicability of proposed model is verified.

Research on Performance Evaluation Technology of Anti-Galloping Fittings in Overhead Transmission Lines

SHANG Quanhong, ZHAO Bin

2017, 50(5):  121-125.  DOI: 10.11930/j.issn.1004-9649.2017.05.121.05

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In order to better understand effects of different anti-galloping fittings arrangements, the nonlinear vibration properties of Shuangxin 5465 line and anlong 5466 line are analyzed theoretically through galloping equations with curved beams and anti-galloping fittings arrangements. Performances of two fitting scheme, namely spacers only and double-spacer pendulum damper combination, are evaluated. Results show that both arrangements have ability to suppress line galloping. However, combination of two schemes are more effective.

Design and Implementation of Online Power Quality Monitoring System

LI Linhui, YANG Junfei, TAN Jun, WU Meng, YIN Chengcai

2017, 50(5):  126-131.  DOI: 10.11930/j.issn.1004-9649.2017.05.126.06

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The basic data of power quality online monitoring system comes from multiple business systems. Multiple business system vendors require complex integration. Under data sharing and business integration framework from State Grid Corporation of China, a unified integration specification is implement by using SG-CIM model. The business information of power quality is integrated efficiently in the platform to satisfy power frequency, voltage and reliability regulatory requirement. The platform targets on data standardization, practical evaluation criteria and improves power quality management efficiency.

Study on Standard Gases Measurement Model and Standard Oil Preparation for Calibration of Transformer Oil

XU Ting, YU Naihai, ZHAO Ruxiang, CHEN Suhong, QI Qiubo, ZHANG Xingmei, QI Guodong, LENG Shubo

2017, 50(5):  132-138.  DOI: 10.11930/j.issn.1004-9649.2017.05.132.08

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In order to test the accuracy of the on-line monitoring devices for dissolved gases in transformer oil, calibration with the standard oil has become the mainstream method. At present, there are mainly two standard oil preparation method, i.e., mixed standard gases method and single standard gas method. In this paper, precautions for application are proposed regarding the mathematical models related to the two methods,. From the comparison between the two preparation methods and the corresponding mathematical models, it is concluded that the single standard gas is more advantageous. Based on the mathematical model of single standard gas method, the automatic standard oil preparation device(automatic oil distribution instrument) is improved and tested through the preparation of the dissolved gases of transformer oil. The study results show that the improved automatic oil distribution instrument is of high accuracy with the oil preparation error of less than ±10%. The piston type stainless steel cylinder is proved to have better performance in oil storage. The concentration stability of the standard oil stored in this type of cylinder can completely meet the inspection requirements.

Generation Technology

Experimental Research on the Performance Analysis Reference of Steam Turbine Flow Path and Its Energy-Consumption Sensitivity Calculation Model

SHAO Feng, TAN Rui, CAI Pei, HUANG Qilong

2017, 50(5):  139-143.  DOI: 10.11930/j.issn.1004-9649.2017.05.139.05

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Based on the equivalent enthalpy drop theory and the small deviation analysis model, a method is derived to calculate the corrections of the monitoring section parameters with other related parameters converted to unified boundary conditions (design parameters). The reference for the flow path performance variation analysis is also unified. The misunderstanding in judging the flow path performance by calculating the deviation between the monitored parameter and the designed value is discarded. By using the simplified Friuli Greig Formula and the reheat theory, a new method to calculate the energy-consumption sensitivity is proposed, which can avoid deeply nested iterative process and realize fast calculation. The method is proved by performance experiments. It is concluded that this method can figure out the main reasons of the flow path performance variation, and obtain the energy-consumption sensitivity of the efficiency of each cylinder and the energy-consumption sensitivity curve of various units.

New Primary Frequency Regulation Technologies for Steam Turbines under Economical Operation Mode

ZHU Jianfei, SHEN Congqi, YAO Jun, MA Jianhua, GUI Yishu, YU Haiyun

2017, 50(5):  144-150.  DOI: 10.11930/j.issn.1004-9649.2017.05.144.07

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Under economical operation mode of throttle admission steam turbines, the sliding pressure operation mode will be enabled with fully-opened high-pressure control valve. However, under this circumstance, the capability of increasing load for primary frequency regulation will be weakened, which makes it difficult to meet the requirement of quick load response to large power grid frequency deviation. Therefore, there exists big contradiction between the economic operation mode and the capability of primary frequency control. In this paper, the technologies of overload control valve adjustment, energy storage utilization in LP and HP regenerative systems, as well as in heat supply system are studied for primary frequency regulation. With the combination of these technologies, in the case of high-pressure control valve at full opening, the unit will increase the load fast when the power grid frequency is low. These technologies may also be used in the steam turbines adopting sequence valve admission to complement the original primary frequency regulation capacity at large frequency deviation.

Study on Boiler Combustion Optimization Model Based on New Temperature Field Measurement Techniques

WANG Ran, ZHANG Zhigang, AN Liansuo

2017, 50(5):  151-155.  DOI: 10.11930/j.issn.1004-9649.2017.05.151.05

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In order to improve the boiler efficiency and reduce the pollutant emissions, it is necessary to conduct the power plant boiler combustion optimization. The development of new temperature measurement techniques has improved the condition monitoring level of the boilers. By using the new temperature field measurement techniques, a boiler combustion optimization model, including temperature field measurements in furnace, is proposed and implemented in the numerical simulation of the furnace combustion process under different operating conditions in a 300-MW subcritical pressure boiler. The combustion optimization model is established and tested following the big data principles. The study results indicate that the model combines the temperature measurement techniques well with the combustion optimization, which is reliable in accurately predicting the effects of boiler operating parameter changes on the temperature field distribution in the furnace.

Experimental Study on Mechanical Properties of S30432 Steel Containing Martensitic Structure

SHI Zhigang, MA Hong, MEI Bao, HE Xiaodong, DONG Hongnian, ZHU Ruihua

2017, 50(5):  156-162.  DOI: 10.11930/j.issn.1004-9649.2017.05.156.07

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In order to evaluate the long-term service security of S30432 steel containing martensitic structure, the mechanical properties and fracture mechanism of S30432 steel are studied by using XRD, SEM, TEM, tensile testing machine, impact testing machine and Vickers hardness testing machine. The study results show that during the 19 000-hour service time, the martensite structure of S30432 steel has induced or exacerbated further increase of room-temperature tensile strength and hardness besides the precipitated phase enhancement as well as the room-temperature aging embrittlement. Affected by the martensite structure, the tensile impact fracture of S30432 steel at room-temperature is formed along the grain boundary regions close to the martensitic structure rather than along the grain boundary precipitated phase of the intergranular fracture toughness, while at high temperature, the fracture exhibits transgranular dimple fracture.

Energy Conservation and Environmental Protection

Application and Demonstration of IGCC-Based Pre-Combustion CO₂ Capture Technology

FAN Qiang, XU Shisen, LIU Yuan, LIU Kang, CHEN Xiong, LUO Lizhen, DONG Shaolong, TAO Jiye, CHEN Zhi, CHENG Jian, REN Yongqiang

2017, 50(5):  163-167.  DOI: 10.11930/j.issn.1004-9649.2017.05.163.05

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The IGCC-based pre-combustion CO₂ capture technology, an efficient and environmental technology which combines the IGCC and CCS together, has attracted extensive attention all over the world. This paper introduces the process flow of the first pre-combustion CO₂ capture system in China, and conducts the analysis on the energy consumption and cost of the capture. The results show that the capture capacity of the system is 94 600 tons/year with the capture rate over 88%. The unit energy consumption is 2.34 GJ/t, and the capture cost is 281.37 RMB/t. At the same time, the improvement direction for waste heat recycling and utilization is put forward. Compared with the conventional post-combustion CO₂ capture technology , the energy consumption and cost of the capture are greatly reduced, which means that it may become the key low cost CO₂ capture technology for fossil fuel combustion in the future.

Assessment of NO_x Distribution and Ammonia Escape Concentration at SCR Outlet after Ultra-Low Emission Retrofit

MA Dawei, ZHANG Qiliang, HUANG Qishun, ZHA Zhiming, HE Jun

2017, 50(5):  168-171.  DOI: 10.11930/j.issn.1004-9649.2017.05.168.04

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This paper takes a 660-MW ultra-supercritical unit for example to study the NO_x distribution and ammonia slip concentration at the SCR denitration outlets after the ultra-low emission retrofit project. The ammonia slip concentration, NO_x concentration, oxygen volume and temperature are measured and tested. It is observed that the NO_x distribution at the outlets is severely uneven, and the ammonia slip concentration is beyond the designed value. In addition, in the area where the ammonia slip concentration is high, the NO_x concentration is low and the denitration efficiency is high. Also at some sampling points, high ammonia slip and NO_x concentrations are observed due to the heavy damage of catalyst caused by the high flue gas flow speed. The test results indicate that after ultra-low emission retrofit, the ammonia injection needs to be optimized and the flue flow field simulation test shall be carried out to improve the operation effect and economic performance of SCR denitration devices.

Analysis and Suggestions on Sulfur Dioxide Emission Control for Coal-Fired Power Plants in China

GUAN Weizhu, CHEN Ou, ZHU Yeqing

2017, 50(5):  172-177.  DOI: 10.11930/j.issn.1004-9649.2017.05.172.06

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The construction, operation and management of flue gas desulphurization facilities have great influences on coal-fired power plants and China started working on the sulfur dioxide emission reduction in coal-fired power plants in a large scale during the 11th Five-Year period. This paper reviews the history of the sulfur dioxide pollution control in coal-fired power plants, makes the summary and analysis from the aspects of policies, regulations, standards, technologies, equipment installation and operation, efficiency improvement as well as emissions control, and puts forward suggestions on total amount calculation method, desulfurization equipment management and comprehensive utilization of sulfur resources. The analysis shows that considerable progress has been made in the control of sulfur dioxide pollution in coal-fired power plants and remarkable results have been achieved on the total emission reduction , but the environmental benefit from the ultra low emission is still low and the new technologies need more improvement. The focus in the next phase should be on the systematic research and the sulfur dioxide concentration control.

A Typical Calculation and Analysis of Carbon Emissions from Coal-Fired Power Plants

GAI Zhijie, WANG Penghui

2017, 50(5):  178-184.  DOI: 10.11930/j.issn.1004-9649.2017.05.178.07

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The United States and China jointly issued “Joint Statement on Climate Change” on September 25, 2015. According to the statement, China will launch the national carbon emissions trading scheme (ETS) in 2017 while the accurate counting of carbon emissions is essential to China’s ETS. In order to make enterprises understand the status of their own carbon emissions, broaden their knowledge reserves in the field of carbon emissions, and master the power industry carbon emissions calculation method, a power plant in Inner Mongolia is taken as an example to illustrate the process of data collection and calculation of carbon emissions in details. The fuel activity levels, fuel emissions factor and carbon emissions, etc. are obtained through calculation. The relationship between CO₂ emissions and power supply are studied quantitatively to evaluate the power plant’s carbon emissions.