Table of Content

25 October 2017, Volume 50 Issue 10

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Special Contribution

Application and Development of Intelligent Inspection Robot System in Thermal Power Plant

ZHANG Yandong, TIAN Lei, LI Maoqing, LIANG Dongxing, CHEN Jianchao, HU Da, WANG Mingjian

2017, 50(10):  1-7.  DOI: 10.11930/j.issn.1004-9649.201706125

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In order to alleviate the situation of frequent occurrence of accidents in thermal power industry and shortage of front-line workers in recent years, an intelligent inspection robot is discussed in detail. With development and integration of intelligent detection technologies, the robot has functions of video image recognition, infrared temperature measurement, laser vibration and voice pickup, drip detection of water, acid, alkali, gas and steam, expert system of data collection, recording statistics and analysis, mobile phone APP remote online monitoring, which can satisfy daily patrol needs of thermal power plant. Demonstration application in thermal power plant shows proposed robot can achieve desired objectives with all designed functions. The testing provides practical experience and optimization direction for further large-scale application and demonstrates feasibility intelligent inspection robot application in thermal power industry.

Telecommunications Technology for Electric Power System

Secure Power Communication Network Architecture Driven by Quantum Key Distribution

CAO Yuan, ZHAO Yongli, YU Xiaosong, ZHANG Jie

2017, 50(10):  8-11.  DOI: 10.11930/j.issn.1004-9649.201708037

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Research on Quantum Encryption of WAN for Power Production Business

WANG Zhenzhen, LU Lifeng, SUN Zhongwei

2017, 50(10):  12-17.  DOI: 10.11930/j.issn.1004-9649.201703014

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Based on the communication characteristics and security requirements of the power production business, a space-ground quantum encryption scheme based on quantum satellite is proposed, and a Faraday-Michelson quantum key distribution system (QKD) independent of line polarization is established for the problem of long distance quantum communication of the terrestrial link in the overhead power transmission environment. The feasibility of the scheme in the overhead power transmission environment is proved by experiments. Finally, the phase compensation technique in the overhead power transmission environment is analyzed.

SDN Control Strategy for Delay Tolerance of Power Communication Service

LIU Chuan, LI Binglin, LI Bozhong, ZANG Liwei

2017, 50(10):  18-21.  DOI: 10.11930/j.issn.1004-9649.201707203

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The balance between real-time and flexibility is one of the key points for application of SDN technology in power communication networks. Delay calculation of transmission network and data network under traditional architecture as well as the influence of two flow table release mode on control delay under SDN architecture are described in the article. In simulation and test environment, through comparative analysis, hop control strategy and hybrid mode flow table release strategy are proposed based on end-to-end service time delay of power communication. It is concluded that 1) the additional control delay introduced by SDN can be controlled by hop controlling to meet the delay tolerance, 2) the hybrid mode flow table strategy can dynamically balance real-time and flexibility under the premise of satisfying the delay tolerance.

Indicator System for Operation Quality of Electric Power Communication Network

XIE Yingjun, WANG Yuting, LI Wei, DING Huixia, WANG Zhihui, ZHANG Shixian, ZHOU Ruankun

2017, 50(10):  22-27.  DOI: 10.11930/j.issn.1004-9649.201707171

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The power communication network is an important infrastructure of the power system, and establishing a correct operation quality evaluation indicator system is very significant for the planning, construction and operation of electric power communication. Since the evaluation factors of existing operation quality evaluation methods are not comprehensive and poor in stability, an operation quality evaluation indicator system of communication network is proposed. Firstly, the system theory is used to analyze and summarize the operation management and decision-making system of electric power enterprises. Secondly, a key indicator system is constructed considering the requirements of vertical and horizontal comparison of the indicators, and then the objective function of the evaluation indicators is designed. Finally, the actual data provided by a power company is taken as an example to evaluate the quality of its communication network, which proves that the method has good feasibility.

Research on Application of P-OTN Technology in Electric Power Backbone Communication Network and Multi-Service Bearing Strategy

WANG Yudong, LIU Wei, LIU Jie, LI Wei, HUANG Xing, MENG Wei

2017, 50(10):  28-34.  DOI: 10.11930/j.issn.1004-9649.201708004

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At present, the IP of electric power communication has become a general trend. Although the tradtional time division multiplexing(TDM) business is small in quantity, its requirement for reliability and real-time are extremely high, which is very important for the security and stability of power grid. As a result, the coexistence of multi-service situation is inevitable in the future. The integration of the existing synchronous digital hierarchy(SDH) or packet transport network(PTN) with OTN network, which can satisfiy the network requirements for service quality and transmission reliability, is an important technical problem that needs to be studied. Based on an analysis of the new demand of electric power business and network models, the application prospect of packet-enhanced optical transport network(P-OTN） technology is explored, and the network model and business bearing strategy are proposed, which can unify business bearing and ensure the quality of TDM service.

Detection Method Against False Data Injection Attack Based on Extended Kalman Filter

HE Yao, ZHOU Cong, ZHENG Lingyue, ZHANG Weixi, XIE Yuxian

2017, 50(10):  35-40.  DOI: 10.11930/j.issn.1004-9649.201707188

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False data injection attacks can destroy the data integrity and availability in SCADA systems, so the detection method for data security and stable operation of smart grid is of great significance. The extended Kalman filter method uses the detected data to recursively obtain the real-time state of the system, so as to achieve the purpose of effectively detecting and checking whether or not there are false data injections in the power system. In addition, this method can not only evaluate the past operating states, but also predict the minute changes of future system. Furthermore, this method can effectively identify the false data injection attack under unknown conditions of the system. IEEE-14 node and 30-node models are used as the benchmarks for detecting false data injection attacks. The results show that the proposed method not only is superior to traditional state estimation methods that fail to detect false data injection attack, but also exhibits many advantages, such as small storage capacity and easy realization.

Application of Ultra-Long Span Optical Transmission Technology Combined with Second-Order Raman Amplify and First-Order ROPA in Ultra-High Voltage Project

ZENG Chang’an, YAO Qing, HUANG Liyan

2017, 50(10):  41-45.  DOI: 10.11930/j.issn.1004-9649.201707170

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With the construction of ultra-high voltage (UHV) transmission network, the ultra-long distance optical fiber communication technology has found increasing applications, and the 10 Gb/s ultra-long distance optical fiber communication has been applied in many UHV projects. According to the main factors that influence the 10 Gb/s transmission system and the application of available technologies in domestic and overseas ultra-long distance optical fiber communication, the paper proposes a construction scheme of experimental circuit for ultra-long distance optical fiber communication based on a multi-terminal HVDC project of China Southern Power Grid. The transmission distance reaches 470 km in the experimental circuit by using ultra-long span optical transmission technology combined with second-order Raman amplify and first-order ROPA. The equipment configuration and software calculation conclusions are presented in the paper. The experiment results will provide valuable experiences for similar projects in the future.

Power System

Onsite Measurement and Analysis of Transmission Line Electromagnetic Environment for UHV AC Demonstration Project

LIU Lina, TAO Jiaxiang, ZHANG Yemao, XIE Huichun, YU Jianqin, GONG Wenjia

2017, 50(10):  46-51.  DOI: 10.11930/j.issn.1004-9649.201607110

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In order to obtain the actual level of electromagnetic environment on 1 000 kV Jindongnan-Jingmen-Nanyang UHV AC transmission lines in the demonstration project, the indexes of electromagnetic environment along the transmission lines at the early stage of the operation were measured, which include 34 electromagnetic environment-sensitive targets, lines across roads and railways, macaques protection areas, angle towers, typical cross sections and so on. this study compared the measured data of the power frequency electric field, magnetic induction intensity, the level of audible noise and radio interference level with the control indexes. the results show that the level of electromagnetic environment around 1 000 kV Jindongnan-Jingmen-Nanyang lines is basically the similar level to those around 500 kV AC transmission lines which means the main index of electromagnetic environment has met the approval requirements of environmental protection.

Research on Safety Protective Measures for Effective Connection Between Design and Construction in UHV Substation Projects

XIONG Zhiming, LIU Jiannan, NI Xiangping, DAI Qiejun, LI Yingying, WANG Xiaosong, ZHANG Da

2017, 50(10):  52-56.  DOI: 10.11930/j.issn.1004-9649.20160209

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At present, UHV projects have already entered large-scale construction stage. UHV substation projects have difficult construction process and high security risks. In order to ensure construction personnel and equipment safety, it is necessary to fully consider feasibility and safety of construction process in engineering project design stage. Two typical kinds of forced regulation violation, caused by disconnection in safety between design and construction stage, are discussed in detail. The two violation cases are “misuse safety ropes in heighted work” and “rule violation of fixing cable wind ropes and traction cable”. Targeted safety protection measures, which consider conditions in engineering design stage for the implementation of relevant safety management rules in construction process, are put forward. Proposed safety protection measures have already been applied in Huainan-Nanjing-Shanghai UHV transmission and transformation project with anticipated effect.

Analysis on Power Receiving Capability of Hunan Power Grid During the Initial Operation of UHVDC Project from Jiuquan to Hunan

GUO Hu, DANG Jie, XI Jianghui, JIANG Wenli, ZHANG Wenchao, LI Chenkun, CHEN Daojun

2017, 50(10):  57-63.  DOI: 10.11930/j.issn.1004-9649.201609061

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Based on current power receiving capability of Hunan power grid, difference between UHVDC and conventional unit is analyzed. Change of power receiving capability of Hunan power grid is calculated according to the latest network and load level during initial operation of UHVDC project from Jiuquan to Hunan. Impacts of different factors on power receiving capability of receiving-end power grid are compared, including load model, synchronous condenser, network modeling mode, power start-up mode, total load level, spinning reserve ratio and important sections power. The impacts on transmission capability of UHVDC project from Jiuquan to Hunan are discussed in detail. From the analysis, load model, synchronous condenser, network modeling mode and power start-up mode have larger impact than total load level, spinning reserve ratio and important sections power. The results offer references for testing and operation mode arrangement of UHVDC project from Jiuquan to Hunan.

Study on Application of HVDC Frequency Limit Control (FLC) in Asynchronously Interconnected Yunnan Grid

MEI Yong, ZHOU Jian, LV Yaotang, XIE Huifan

2017, 50(10):  64-70.  DOI: 10.11930/j.issn.1004-9649.201701069

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Asynchronous interconnection between Yunnan province power grid and China southern main grid increases system frequency stability risk. The Frequency limit control (FLC) of HVDC realizes quick and large range power modulation, and is very helpful to maintain system frequency stability. Based on actual operating conditions in Yunnan, some problems of FLC application in provincial area power grid are analyzed comprehensively, including principle of function configuration, regulation range, dead band configuration, HVDC overload. FLC dynamic response characteristics are analyzed with case study. A field implementation plan is also proposed. The successful experience of FLC application in Yunnan provincial grid provides valuable reference and guidance for follow-up project.

Joint Distribution Calculation with Probabilistic Power Flow Considering Dependencies Among Multiple Wind Power Generations

TIAN Bei, YU Zhen, LI Xutao, LI Hongqiang, SHEN Chen

2017, 50(10):  71-77.  DOI: 10.11930/j.issn.1004-9649.201702093

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With large-scale wind power connected to power grid, wind generation fluctuation brings more uncertainties to power grid operation and seriously threatens power system static security. A joint distribution calculation method of probabilistic power flow considering dependencies among multiple wind power generations is proposed, which can be used to evaluate influence of wind generation on power system static security. Firstly, the Gaussian mixture model is used to characterize joint probability distribution of multiple wind power generations accurately. Then, based on excellent property of the Gaussian mixture model and approximate linear relationship between system state variables and wind power generations assumption, analytical expressions of joint probability distribution of system state variables are obtained. This method is applied to probability assessment of static security in Ningxia power grid. Compared with Monte Carlo simulation method, the proposed method has higher accuracy and faster computation speed.

Optimization on High Speed Avalanche Test Model for Multiple IEC 61850 Server Simulation

FANG Fang, WU Dongqi, SHU Peng, LIU Zhanpeng, LI Peng, LI Jianbo

2017, 50(10):  78-82.  DOI: 10.11930/j.issn.1004-9649.20160017

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Regarding the functional testing and stress testing for the substation level host and tele-control devices, such as avalanche concurrent test and MMS link capacity test involving several hundreds of devices, it is very time and effort consuming to build the actual test environment. Therefore the software simulation turns out to be the only way to perform the testing. In this paper, the authors first elaborated the principle and structure of the device server simulation of MMS. Then based on virtual machine technology and the time slice rotation principle in multi-server simulation system, the high speed avalanche test model is optimized, which is capable of sending 1 200 reporting service data for 300 devices successfully within the tens of milliseconds range. The research accomplishments can shorten the time spent on the establishment of the test environment at the client end, optimize the speed of the avalanche concurrent test, and hence effectively verify the client database and the real-time processing capability.

Development and Application for an AC Withstand Voltage Equipment Without Power Outage of GIS

GU Qiang, JIN Xin, YUAN Ting, ZHENG Deguo, LI Guanhua

2017, 50(10):  83-88.  DOI: 10.11930/j.issn.1004-9649.20160039

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Alternating Current (AC) withstand voltage test is indispensable in hand-over test procedures for switch apparatus, which must be done under the condition of power outages. To explore the way for the AC withstand voltage test without any power outage, the method using synchronized frequency and phase for AC withstand voltage was proposed, and a test device was designed based on the corresponding principle. The results demonstrated that this method is applicable to the substation without any power outage. The designed test device has passed the testing and assessment under different abnormal working conditions in the laboratory and then applied successfully for onsite testing such that its effectiveness is verified.

Experimental Study on Seismic Performance and Structural Characteristics of ±800 kV Composite Post Insulators

CHENG Yongfeng, LIU Zhenlin, LU Zhicheng, ZHU Zhubing, LI Sheng, LIU Hailong

2017, 50(10):  89-96.  DOI: 10.11930/j.issn.1004-9649.201702052

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In order to analyze the structural characteristics and seismic performance of composite electrical equipment, a seismic shake table test is conducted on two types of ±800 kV composite post insulators used in the electric power projects, i.e., post structure with support and post structure without structure. The displacement, strain and acceleration responses of the key parts of the equipment are measured through white noise and seismic test. A comparative analysis is made of the seismic responses of the composite post insulators with/without support. The experimental results show: 1) the support slightly reduces the first order frequency while increasing the damping ratio of the test equipment, but has less influence on the damping ratio of the flexible equipment; 2) the stress and displacement responses are basically linear under the seismic excitation of 0.1 g to 0.4 g; 3) the support dynamic amplification coefficients of stress, displacement, acceleration and spectral acceleration are all less than 1.30 with the amplification coefficient of peak acceleration being the largest; 3) the support amplifies the spectrum of seismic waves in the part of high frequency, and 4) the structural frequency distribution of equipment on the seismic wave spectrum curve is positively related to the amplification factor of the support stress, and the support slightly enlarges the equipment displacement.

Generation Technology

Cause Analysis on and Solution to Abnormal Reheat Steam Temperature of Boilers

ZHAO Zhenning

2017, 50(10):  97-103.  DOI: 10.11930/j.issn.1004-9649.201701084

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Abnormal outlet reheat steam temperature is a common problem for boilers. Facing the issues of low pressure and low specific heat capacity of reheat steam, its temperature-sensitiveness to changes of absorbed heat and the evident negetive effect on the total unit efficiency due to the desuperheater water amount reduction, the reasons why the arrangement of lean-margin reheating heat exchange area and the flue-gas-side temperature adjustment on the reheat steam temperature are adopted in the boiler design are anlyzed. They are also found to be the root causes of why the reheat steam temperature is so easily disturbed by the minor operation changes such as coal type, the boiler combustion mode, the exhausting steam temperature of turbine high pressure cylinder. Targeting at these factors, the phenomena, laws, judgment methods and the corresponding measures to solve theabnormal reheat temperature problem are discussed and summarized. to It is emphasized that the right order to solve this problem should be comprehensive analysis, combustion adjustment, and reheater retrofit. The advantages and disadvantages of three methods-adding serial radiant reheater, adding serial convectional reheater and adding parallel convectional reheater, are discussed in order to meet the strict demands of reheater retrofitting. By comparison, it is concluded that the method of adding parallel convectional reheater works better than the other two. The study result may provide references for sovling the abnormal reheat temperature problemes.

Numerical Simulation on the Operation Optimization of Tiny Oil Ignition Burner

HUANG Xiangbin, WANG Huajian, BAI Peng, YAN Xianglin

2017, 50(10):  104-109.  DOI: 10.11930/j.issn.1004-9649.201604158

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A precise physical model is developed for the tiny-oil ignition burner in a 330 MW tangentially-fired boiler, including the primary air, the surrounding air and the burner thick wall areas. The three dimensional numerical simulation on the fluid flow process, combustion and fluid-solid coupled heat transfer in these areas are conducted under the bituminous coal combustion conditions. The effects of oil gun flow rate on the ignition performance and the wall temperature are carefully analyzed for the oil flow rate optimization. The calculated temperature matches well with the measured value at the monitoring points. The calculated results show that appropriate oil flow rate reduction not only has little side effect on the ignition performance, but also can lower the wall temperature of the burner. Theoretically the oil flow rate should be kept at 70 kg/h as the minimum requirement for the coal type of the boiler. In practical operation it can be adjusted to 80 kg/h to ensure sufficient secure margin. According to the practical operation data, with the oil flow rate at 80 kg/h, although the maximum and average temperatures at the burner exit have all been somewhat decreased, the operation parameters and indices of the boiler still remain normal and meet all the requirements for successful ignition.

Analysis on High Temperature Corrosion of a 600 MW Boiler Furnace After Low NO_x Combustor Retrofitting

HE Guilin, ZHANG Xiaoyu

2017, 50(10):  110-115.  DOI: 10.11930/j.issn.1004-9649.201702103

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Aiming at the problem of corrosion occurred in the cold ash hopper area of a 600 MW coal-fired boiler after low NO_x combustor retrofitting, the cause analysis is conducted in this paper by adopting testing and numerical simulation. The test results show that the volume fractions of H₂S and CO have bigger promotion at the primary and reducing zones of the furnace after retrofitting. The temperature field and flow field are analyzed through numerical simulation and the causes of high temperature occurrence are concluded as follows. Due to the palm air volume decreasing, the combustion deteriorates in the burners of Layer A, and the pulverized coal tends to deposit and burn at the bottom of the furnace. Therefore, the high temperature zone is formed. At the same time, lack of oxygen at the bottom of the furnace, and the high volume fraction of gases such as H₂S, make it easy to cause high temperature corrosion.

Analysis on the Dynamic Vibration Absorption of Bearings of the Large Turbo Unit

WU Yajun, YANG Tianhai, JIANG Chaohui, YANG Jiangang, CAO Zhongxun

2017, 50(10):  116-119.  DOI: 10.11930/j.issn.1004-9649.201703019

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Aiming at the abnormal structural vibration occurred on the bearings of large turbo units, the dynamic model of the rotor-bearing-support system with flexible support is set up to analyze the abnormal structural vibration phenomenon using the dynamic vibration absorber theory. The result shows that the support stiffness of the bearings located on the exhaust cylinder is low. The natural frequencies of the bearings and the rotor system may be reduced from more than 50 Hz as being designed to less than 50 Hz. Once the natural frequencies of the bearings and the rotor system are superposed, the vibration absorbing phenomenon tends to occur. The shaft vibration transfers to the bearings, resulting in small shaft vibration and large bearing vibration. At this time, the system natural frequency is decomposed into two, which are distributed on both sides of the natural frequency. Consequently, a double resonance peak appears.

Effect of Low Frequency Oscillation of Power System on Operation Safety of Steam Turbine Unit

ZHANG Bao, FAN Yinlong, YIN Xuyang, HU Zhou, GU Zhenghao

2017, 50(10):  120-123.  DOI: 10.11930/j.issn.1004-9649.201703014

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The low frequency oscillation of the power system has occurred many times in China, which endangers the safe operation of the steam turbines. Based on the specific cases, the different reactions of the steam turbines during the low frequency oscillations of the power system are analyzed. It is pointed out that the low frequency oscillation of the power system is threatening the safe operation of the unit in two ways. One is the speed measurement and the other is the turbine valve opening fluctuation. Through the actual testing, it is observed that the control oil pressure of a unit declines continuously when the low frequency oscillation occurs. Taking China’s situations into account, it is suggested that measures should be taken to improve the anti-interference ability of the control oil system, and contingency plans should be made.

Study on Setting Value Tuning of PSS Automatic Power Action and Return for Coal-Fired Units

LU Haiqing, WU Kuayu, LU Cencen

2017, 50(10):  124-128.  DOI: 10.11930/j.issn.1004-9649.201608118

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This paper analyses the causes of the power system stabilizer (PSS) frequent act and return as well as long-term offline during the normal operation of the coal-fired units. Taking the logic of PSS power automatic action and return and the three factors affecting the operating condition of the coal-fired units into account, the paper proposes a method of setting value tuning that is suitable for coal-fired units’ PSS power automatic action and return. By using this method, the PSS action and return setting values of a 1 000 MW coal-fired unit are optimized. The optimization is able to eliminate the PSS frequent act and return and long-term offline. The result shows that the method is easy to practice and applicable in the industry.

Application of Constrained Predictive Control in Steam Temperature Control System of Low NO_x Combustion Power Unit

QIAN Hong, Chen Dan, YANG Zukui, ZHENG Pengyuan

2017, 50(10):  129-135.  DOI: 10.11930/j.issn.1004-9649.201605071

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In view of the problems of combustion delay and steam temperature heavy fluctuation in the generation process of a low NO_x combustion power plant, a predictive control algorithm with constrained optimization is proposed and applied to the superheated steam temperature control system of the power plant to construct a cascade compensation predictive control system, which is verified through simulation. The simulation results show that with the constraints of the superheated steam temperature cascade predictive control system, the controlled variable can be restrained effectively within the constraint range, and the system has the anti-jamming and robustness characteristics better than those of the conventional control system. Therefore, the superheated steam temperature control quality has been greatly improved.

Energy Conservation and Environmental Protection

Test and Study on Synergic Mercury Removal Performance of Environmental Protection Facilities at Ultra-Low Pollutants Emission

CUI Liming, HUANG Zhijie, MO Hua, ZHU Jie, JIANG An, HUANG Ru

2017, 50(10):  136-139.  DOI: 10.11930/j.issn.1004-9649.201707168

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The test on mercury emission and distribution is carried out synchronously at multi-points in some ultra-low pollutants emission power plants. It is discovered that the mercury removal efficiency by WFGD is about 22.2%~80.35% and that by WESP is about 0%~71.4%. The mercury removal efficiency by WFGD is correlative to the mercury morphology at the entrance of WFGD, the unit load and the gas-liquid mass. WESP shows limit effect on the mercury capture when the mercury concentration at the entrance of WESP is low.

Current Status of the SCR DeNO_x Catalyst Quality for Thermal Power Plants

ZHANG Jun, YAO Jie, ZHUANG Ke, WU Bijun, JIN Dingqiang

2017, 50(10):  140-143.  DOI: 10.11930/j.issn.1004-9649.201701030

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To standardize the quality supervision and management of deNO_x catalysts, sampling and spot checks for the newly-purchased SCR de-NO_x catalysts for thermal power units are made mandatory by all the power groups of China. The statistical results from a professional testing institute in 2016 show that a large number of newly-purchased catalysts have certain defects or drawbacks, of which 57.1% are of dimension deviation and 54.3% have appearance defects, 48.6% and 54.3% are of compressive strength and abrasion ratio below the standards respectively. There are also 8.6% of the catalysts whose activities and specific surface area are less than the standard limits, and 62.9% and 5.7% of which have less main component (WO₃) contents but higher contents of micro elements than what is specified in the technical protocols. From the results it is evident that the current situation of the quality of domestic SCR deNO_x catalyst supply is still severe, which urgently calls for more regulation and management.

Control Method and Application of Novel Automatic Oxygen Injection Technology

GUO Jinping, WANG Zhao, ZHANG Xiaohong, WANG Ningfei

2017, 50(10):  144-147.  DOI: 10.11930/j.issn.1004-9649.201608114

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In order to ensure the constant concentration of dissolved oxygen during unit load fluctuations, a new automatic oxygen injection technology is proposed, i. e. liquid state constant value automatic oxygen injection technique. By taking the advantage of the characteristics of incompressibility of liquids, the technique mixes pure oxygen with salt water sufficiently after they are pressurized and then the mixture is injected into the water supply system through the oxygen injection pipeline. In this way, the defect of the compressibility of oxygen can be avoided such that rigid dosing of oxygen dissolving is implemented in the desalted water. This technique has been implemented in a number of thermal power units with oxygen injection. From the results of the practices it is evident that even with random changes of feed water volume, the dissolved oxygen fluctuation will still be maintained within ±3 ug/L by using this technique. Therefore, the inherent difficulty of repetitive fluctuation of dissolved oxygen following the unit load change with gaseous oxygen-injection is solved completely. this technology can provide a strong technical support for the continuous operation, energy conservation and emission reduction of the power units.

Determination of Dissolved Gases in Transformer Oil with Gas Chromatographic Helium Ionization Detector

DENG Xianqin, PENG Wei, LI Minxian, XIONG Mingxiang, PAN Rui, ZHUANG Hongtao, FANG Hua

2017, 50(10):  148-152.  DOI: 10.11930/j.issn.1004-9649.201610081

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Characterized by big volume and large o amount of oil in ultra high-voltage(UHV) transformers, the concentrations of the characteristic dissolved gases relating to malfunctions may become too low to be monitored normally by certain equipment if the detection limit of the testing method is not low enough. Thus a new testing method adopting gas chromatography (GC) with helium ionization detector (PDHID) is proposed, using the technology of helium ionization detector supplemented with ten-port valves, heart cutting and back flush to carry out the separation and analysis for 7 kinds of dissolved gases (H₂, CH₄, C₂H₆, C₂H₄, C₂H₂, CO and CO₂) in single injection within 7 minutes. The detection limit can reach 10-9 grade. Especially for C₂H₂ and H₂, the detection limit can reach 5×10^-9and 11×10^-9, respectively. The repeatability of the method is about 1% with the linearity correlation R² of all the components higher than 0.99. Compared with traditional GC, the new method of GC with PDHID is easier to operate, and the detector has much stronger peaking signal with the detection limit increased by 5-80 times. Moverover, hydrogen is no longer needed as the auxiliary gas such that the potential risk is reduced. Using the method to analyze the dissolved gases in the transformer oil is of great significance to discover the potential internal malfunctions of the UHV transformers in a timely way.

New Energy

Research on “Grid-Generation-Storage-Load”Coordinative Planning in High Renewable Energy Penetration Region-Case Analysis of Anhui Jinzhai

JIN Wei, LI Zong, GE Fei, CHEN Yi, MA Jing, XU Jiayin

2017, 50(10):  153-158.  DOI: 10.11930/j.issn.1004-9649.201608053

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To cope with rapid development of renewable energy, and meet requirement of “Energy-Internet” development, a research on “grid-generation-storage-load” coordinative planning is performed. Jinzhai, an area which has been planned to develop large scale renewable energy is investigated as example. Measures including energy storage devices, regulating hydro power and active load control, are adopted to fully utilize existing grid resources thus renewable energy can be accessed and consumed locally. Complementary characteristics of wind and solar power generation is studied. Renewable energy is also coordinated with optimal operation of bulk thermal power and pumped storage hydro plant to reduce power sent out volume.

Research on Comprehensive Control Strategy of Distributed Energy Storage MMC

JI Yu, WANG Shengqiang, CAO Yang, XIE fei, XU Xiaoyi

2017, 50(10):  159-165.  DOI: 10.11930/j.issn.1004-9649.20160193

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Distributed energy Storage MMC is a derived structure of MMC where the energy storage unit is integrated in the submodule. Thus energy storage units are decentralized and modular. Meanwhile, Distributed energy Storage MMC has a lot of advantages including high voltage, large capacity, low THD and high fault tolerance. These advantages make it applicable in many fields, for instance, large-scale energy storage, motor drive, renewable energy generation. The working principle of converter is analyzed too. SOC control, energy management mechanism and battery energy storage circuit charging and discharging control are introduced, that realize comprehensive coordination control of system. Simulation results based on Matlab/Simulink and hardware experimental prove superiority and correctness of proposed control strategies.

Technology and Economics

Study on Multi-attribute Comprehensive Evaluation Method of Clean Coal Power Generation Technology

LIU Tong, ZHANG Huicong

2017, 50(10):  166-170.  DOI: 10.11930/j.issn.1004-9649.201703016

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In order to objectively evaluate the clean coal utilization technologies in the power industry and provide references for the elimination of small capacity units, the multi-attribute comprehensive evaluation method is used to construct an evaluation system of clean coal power generation technology for comprehensive assessment from the four aspects of technologies, resources consumption, pollutant emissions and cost-effectiveness. The evaluation results show that the integrated coal gasification combined cycle power generation technology has the best environmental performance, but its cost-effectiveness is the worst. The supercritical/ultra-supercritical pulverized coal furnace unit has even performance in all aspects. Compared with the supercritical pulverized coal furnace unit, the supercritical circulating fluidized bed unit is competitive in general performance, especially in environmental performance, while the former one performs better in cost effectiveness.

The Problems and Countermeasures About Abandoned Water in China Southwest Hydropower Station

SHUAI Wei

2017, 50(10):  171-175.  DOI: 10.11930/j.issn.1004-9649.20160012

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There are abundant hydropower resources in southwest China. The development and utilization of southwest hydropower has an important strategic significance for optimizing China’s energy structure and promoting the development of low carbon economy. Recently, the abandoned water in the southwest hydropower stations has attracted much more attentions and been widely concerned. This paper studies the present situation and problems, and puts forward some important countermeasures and suggestions for reasonable and efficient exploitation of hydropower in southwest China according to a number of factors in terms of the power system planning, power distribution network planning, environmental protection policies, market, and interest reallocation mechanism.

Research on Electricity Consumption Behaviors of the Capacity Expansion Users Based on Big Data Analysis

ZHOU Qi, YANG Jie, HAN Junjie, LUO Xin, ZHAO Ran

2017, 50(10):  176-180.  DOI: 10.11930/j.issn.1004-9649.201602019

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The capacity of business expansion has a close connection with the electricity consumption level. This paper analyses the relationship between the capacity and power consumption, and uses the big data method to study the periodic characteristics for various business expansion capacities to be changed into the electricity consumption levels of electricity users. Based on the mechanism of electricity consumption, the change of the electricity consumption with the business expansion is analyzed, which can provide a comprehensive information support for improving the forecast of electricity consumption.

Application of Data Mining Technology to Build the Anti-Stealing Management System

LIU Sheng, ZHU Cuiyan

2017, 50(10):  181-184.  DOI: 10.11930/j.issn.1004-9649.20150116

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The current anti-stealing management mode is unable to meet the needs of anti-stealing management under the new situation, and data mining is a powerful tool to meet the needs. Based on the accumulated various data source systems from power companies, extracting information using data mining techniques to build an anti-stealing management system, which shares resources and supports decisions, is proposed in this paper. The system design, data processing, modeling and technological realization are introduced, and the offset-degree of line-loss, difference degree of electricity, imbalance of voltage and current as well as other aspects are analyzed.