Table of Content

05 April 2018, Volume 51 Issue 4

Previous Issue    Next Issue

Design and Implementation of Distance Measuring and Warning Device for Live Working

HUANG Xiongfeng, XIAO Canran, ZHANG Yujiao

2018, 51(4):  1-6,14.  DOI: 10.11930/j.issn.1004-9649.201607085

Asbtract ( )   PDF (5848KB) ( )  

References | Related Articles | Metrics

During maintenance and repair work in power system operation, it is vital to keep certain distance between operation personnel and electrical power equipment, which is relying mainly on human observations unfortunately. Due to human errors such as misjudgment or negligence, equipment damage and human casualties may occur consequently. To meet the requirement of real-time safe working distance measurement, a distance measuring system based on high precision ultrasonic sensor, and using STM32 MCU as the core processor is designed for live working. Through wireless WiFi communications, the challenges of wiring with the device near high voltage charged equipment is solved successfully. Meanwhile this device is tested in Jingmen 1000 kV EHV Substation. The results show that the safety distance measuring system has effective safety protection functionality and it can timely alert the operator. It is of great significance for the safety of personnel and equipment.

Security Stability Analysis and Control Strategy of Sending-End Power Grid of ±800 kV Yan-Huai UHVDC

PAN Jie, ZHENG Huiping, ZHANG Hongli, WANG Chao, XUE Zhiwei, LIU Fusuo, WU Chenxi

2018, 51(4):  7-14.  DOI: 10.11930/j.issn.1004-9649.201707130

Asbtract ( )   PDF (3684KB) ( )  

References | Related Articles | Metrics

Security and stability characteristics of sending-end grid of Yan-Huai UHVDC is analyzed in detail. The UHVDC system is a wind-thermal-bundled system without support of thermal power generation. The influence of different connection methods on transient voltage of wind generator after one-time commutation failure of Yan-Huai UHVDC is analyzed. Generator tripping control strategy is proposed with consideration of power transfer and voltage stability in areas close to converter station and north Shanxi area. A deployment scheme of stability control devices is designed to realize cooperative control of tripping generators in different areas. Considering different spare levels of generators, pre-control operation powers of Yan-Huai UHVDC are proposed after analyzing coupling characteristic of stability control systems between sending-end system of Yan-Huai UHVDC and North Shanxi. Risk of generator tripping due to insufficient capacity is quantified after success operation of two sets of stability control device. Simulation results and analysis based on real-sized power grid in China prove rationality and effectiveness of proposed control strategies. The simulation and analysis result provides references for stability analysis and control strategy development of the similar sending-end system of UHVDC projects.

Real Time Assessment and Early Warning of Pollution Flashover and Wind Deflection Risk of UHV Transmission Lines Based on Meteorological Factors

ZHAO Chun, SONG Tunfang, PENG Bo, WU Dawei, TAO Hantao, DENG Yongqing

2018, 51(4):  15-21,66.  DOI: 10.11930/j.issn.1004-9649.201701044

Asbtract ( )   PDF (4962KB) ( )  

References | Related Articles | Metrics

Due to the fact that UHV transmission lines have long distance and can be easily influenced by different meteorological conditions, it is of great significance to have a real-time assessment and early warning of the electrical reliability of UHV transmission lines under different meteorological conditions in order to ensure the stable and reliable operation of power system.This paper analyzes the mechanism of transmission line pollution flashover and wind deflection flashover, and introduces the meteorological parameters into real-time assessment and early warning of the electrical reliability of UHV transmission lines. With consideration of the numerical weather forcasting results for the next 1-72 hours, a real-time assessment and early warning model of UHV transmission line flashover and wind deflection risks is established based on meteorological parameters, which can predict the pollution flashover and wind deflection flashover voltage of transmission lines under different meteorological conditions and give early warnings based on their risk levels, realize the risk assessment and warning.

Insulation Condition Assessment of Transformer Bushing Based on Fuzzy Comprehensive Evaluation

LI Zhichao, LI Weiguo, XIA Yu, ZHANG Shuqi, TANG Hao, JIA Pengfei, CHEN Shaojun

2018, 51(4):  22-26,60.  DOI: 10.11930/j.issn.1004-9649.20160400

Asbtract ( )   PDF (4683KB) ( )  

References | Related Articles | Metrics

To solve the problem that overall assessment of transformer is too general, a fuzzy comprehensive evaluation model is constructed for transformer bushing insulation condition assessment. Due to the fact that constant weight may cause distorted evaluation, the variable weight is introduced to make the evaluation results close to the actual condition of transformer bushing, and the semi-trapezoid distribution function is adopted as a membership function to determine the fuzzy matrix. The ranking eigenvalue is used as a comprehensive rank to determine the condition level of transformer bushing. The case study verifies that the fuzzy comprehensive evaluation is reliable and practical for transformer bushing condition assessment.

Research on Power Grid Fault Judgment Model Based on Gray Experience Fusion

LV Xiaohong, ZHANG Min, CAO Wenzhong, XIONG Laihong

2018, 51(4):  27-32.  DOI: 10.11930/j.issn.1004-9649.20160024

Asbtract ( )   PDF (3402KB) ( )  

References | Related Articles | Metrics

In order to deal with the difference between power grid fault judgment experience and field data, a novel model is proposed for power grid fault judgment based on gray experience fusion, and its frameworks, processing flow and main algorithms are presented. The model utilizes the gray information fusion method to integrate the expert experience and field data. Then the cluster matching method is used to extract the expert experience that is highly similar to the field data and to realize the judgment of present faults. In the end, the expertise database is optimized through integration of the final judgment results, disposal schemes and field data. Comparative experiment illustrates that the model has high fault judgment accuracy, comprehensive fault coverage and better time effectiveness.

Impact of Wind Centralized Access on System Short Circuit Current

LI Yuanyuan, SUN Zian, ZHANG Zhigang, ZHANG Shiqiang, ZHANG Lingkang, JIA Honggang, ZHANG Xin

2018, 51(4):  33-38,88.  DOI: 10.11930/j.issn.1004-9649.201705123

Asbtract ( )   PDF (5384KB) ( )  

References | Related Articles | Metrics

With centralized integration of large-scale wind farms, the influence of wind power on short circuit current has become an important concern in power planning and operation. Short circuit characteristics of various wind turbines are analyzed in detail. Bus short circuit currents are simulated with practical examples under different access form, wind turbine type and installed capacity. The influence of wind power on short circuit current of near area is revealed from different aspects. Considering limiting factors of short circuit current, certain wind farm access forms and wind turbine types are recommended. The results have important reference for planning and construction work of large scale wind power.

Study on Lighting Protection Situation and Device of 10 kV Distribution Lines

QIN Ruyi, LIU Zongliang, CHEN Zhou, XU Chongyou, WU Jun

2018, 51(4):  39-44,95.  DOI: 10.11930/j.issn.1004-9649.201708146

Asbtract ( )   PDF (6437KB) ( )  

References | Related Articles | Metrics

Lightning-caused line break became more and more serious with application of 10 kV Insulation-covered distribution lines. According to statistic, 49% of lightning stroke tripping happen on distribution lines. It is necessary to develop lighting protection device to reduce lightning-caused break probability and improve power supply reliability. By taking typical 10 kV distribution lines as example, the situation and tripping scenarios are analyzed in detail. An arrester with two cascade gaps are adopted and improved. The spherical electrode and main gap parameters are determined by experiments. The volt-second characteristic of lightning impulse and current cut-down ability are also tested. The lighting protection ability of arrester with two cascade gaps are both verified by engineering application.

Analysis on the Interfacial Issues of Running Composite Insulators

WANG Kang, ZHU Yazhou, ZHOU Xinnan, WU Zhaoguo, HU Yuanxiang

2018, 51(4):  45-52.  DOI: 10.11930/j.issn.1004-9649.201702040

Asbtract ( )   PDF (4445KB) ( )  

References | Related Articles | Metrics

In order to study the interface problems of running composite insulator, 37, 68 and 38 composite insulators with different operating years are selected respectively from Guangdong, Guangxi and Hebei areas to test the performance of the interfaces between the core and sheds, between fittings, cores and sheds material, and between the housing and sheds. It is discovered by using the statistical analysis method that 50% of the early composite insulators have poor bondings between the housing and the core; the end fittings and sealants become invalid in various extents; 83.8% of samples from Guangdong area become invalid in the seal between the inside of fittings and tope of the core; 78% of the samples from Hebei and Guangxi areas are degraded. The composite insulators made by compression technology is poor in bonding between the housings and sheds and can be stripped easily by hand. Aimed at the poor sensitivity of the method defined in the standard to detect the interface performance, a new method is proposed to test the interface performance through detecting the variation of DC leakage current of samples before and after boiling.

Analytical Method of GIS Faults Based on Ultrasonic Diagnosis

ZHOU Dianbo, DING Dengwei, GAI Shicheng, JIA Zhijie, WANG Jie, MA Xiaomin, YAO Chenguo

2018, 51(4):  53-60.  DOI: 10.11930/j.issn.1004-9649.20160145

Asbtract ( )   PDF (4870KB) ( )  

References | Related Articles | Metrics

To improve on-site detection efficiency of partial discharge of gas insulated switchgear (GIS), a study is made in this paper on the analytical methods of GIS fault based on ultrasonic diagnosis. According to plenty of data collected on site, the time domain and phase distribution features of ultrasonic signals of typical GIS partial discharge are analyzed, and the differences in time domain features and frequency domain distribution between partial discharge signals and mechanical vibration signals are identified. The paper also studies the application of the joint ultrasonic and electromagnetic wave localization method, the ultrasonic time-delay localization method, and the ultrasonic wavelet time-frequency localization method in on-site GIS partial discharge detection. The detecting results indicate that the proposed methods are reliable in accuracy and correctness.

Analysis of the Impact of Microbial Degradation on the Insulation System of the Offline Capacitive Voltage Transformer

WANG Jie, SU Changhua, WU Xiaohui, ZHANG Li, HU Shihong, LAN Xinsheng

2018, 51(4):  61-66.  DOI: 10.11930/j.issn.1004-9649.201611028

Asbtract ( )   PDF (3714KB) ( )  

References | Related Articles | Metrics

To improve the safety of the capacitor voltage transformer (CVT) operation, it is necessary to study why the amount of the gas contents such as CH₄, H₂ and CO₂ in the oil-paper insulation system of the offline CVT increases. The microorganism growing experiment in the oil-paper insulation system of the CVT is conducted by using the methods of natural inoculation, artificial inoculation and high-temperature sterilization. The microbial degradation products and their amounts are determined with the gas chromatograph, the micro water detector and some other equipments. The microorganism species are identified with the molecular biological method, and the degradation characteristics of the insulation system are analyzed. The results show that the H₂O, acids, CH₄, H₂, and CO₂ are produced during the microbial degradation in the oil-paper insulation system and the components are the same as those found in in the insulating oil of the offline CVT Also, an inflection point of decrease is observed in the gas component increasing process. Four spherical anaerobic microorganism species are detected by microscopic observation and biological identification. It is concluded that the bio-degradation of the oil-paper insulation system of the CVT has two stages, the multi-microbial degradation and anaerobic methane fermentation. The CH₄, H₂ and CO₂ are the characteristic gas produced from the degradation.

Analysis on Ammonium Sulfate Deposition in Tail Flue of a 1 000-MW Ultra-supercritical Coal-Fired Unit

XIAO Jiafan, TAN Houzhang, LIU Hexin, WANG Yibin, DONG Kun

2018, 51(4):  67-74.  DOI: 10.11930/j.issn.1004-9649.201708250

Asbtract ( )   PDF (6125KB) ( )  

References | Related Articles | Metrics

The ultra-low emission technology can effectively reduce pollutant emissions from coal-fired units and improve the air quality. In order to explore the mechanism of fouling in the tail flue of ultra-low emission units, this paper takes the fouling ash on the induced draft fan and the second stage low temperature economizer (LTE) of a 1000-MW unit with ultra-low emission as the research object. The ash samples are examined by using the elemental analyzer, the X-ray fluorescence spectrometer, the X-ray diffraction and the scanning electron microscopy. Then, the major factors contributing to the formation of the crystalline mineral phase of the ash and the ash deposition occurrence at different locations are analyzed and discussed in details. The results show that the ashes on the blades of the induced draft fan and the second stage LTE are mainly comprised of (NH₄)Al(SO₄)₂·12H₂O, (NH₄)₃H(SO₄)₂, CaSO₄ and SiO₂. Among them (NH₄)₃H(SO₄)₂ covering on the surface of the ash particles is the immediate cause of the severe ash deposition on the induced draft fan and LTE, while, the root cause is determined as the ammonia escape from the SCR. At last, this paper suggests that the temperature drop of the flue gas at the first and second stage economizers should be properly distributed considering the sulfur contents of the coal, the ammonia emissions and the ash concentrations, so as to prevent the ESP being operated out of low-low temperature conditions and avoid drastic flue gas temperature drop at the second stage LTE which may cause the rapid condensing of sulfuric acid mist.

Peak Capacity Analysis for Coal Power Development in China

YAN Xiaoqing, TAN Xue

2018, 51(4):  75-80.  DOI: 10.11930/j.issn.1004-9649.201708055

Asbtract ( )   PDF (3245KB) ( )  

References | Related Articles | Metrics

The "13th Five-Year" is the critical period for the energy reform in the power industry of China. One of the issues that requires urgent solutions is the structural oversupply of electricity power, especially the coal power. In order to ease the excessive coal power supply, policies have been introduced by the National Energy Board to control the scale of the coal power generation capacity strictly. The reasonable level of the coal power development, its scientific layout and the construction timing are becoming more and more important. In this study, the comprehensive effects of the coal power reduction policies on the power industry development and the operation of the power system are analyzed. A full-life cycle cost model of the coal power is established and integrated into the whole process of the power planning and the production simulation analysis. The pattern of electric power development in the "13th Five-Year" and the mid-long term in China are optimized by using the proposed model. The results show that the peak capacity of coal power in China should be between 1.15~1.2 billion kW around 2025. The research result is expected to be helpful to the power industry in the "14th and 15th five-year" periods, enhancing the efficiency and safety of the power system.

Experimental Study on Thermodynamic Characteristics of Optimized 1 000 MW Steam Turbines with Variable Back Pressure

BAO Jinsong, QIN Pan, LOU Kewei, ZHU Meifang, WU Ruikang, LI Jun

2018, 51(4):  81-88.  DOI: 10.11930/j.issn.1004-9649.201711159

Asbtract ( )   PDF (4460KB) ( )  

References | Related Articles | Metrics

The variations of steam turbine operating back pressure will impact not only the thermal performance, but also the operation efficiency of the LP casing greatly because of the change of the exhaust volume flow. Through the back pressure variation test under different loads, the thermodynamic characteristics subject to the back pressure changes are studied for the Dongfang optimized 1000-MW steam turbine, from which the influencing formulas of the back pressure on the output and the heat rate are obtained as well as the relationship curve between the LP casing efficiency and the exhaust volume flow. The operating characteristics of the LP casings are analyzed, and the operation back pressure limits of the turbine are estimated. At last, suggestions are put forward on improving the operation efficiency of the LP casings. The test results and analysis show that the turbine equipped with 1 200-mm last stage blade has higher efficiency and better working characteristics of the LP casings in the back pressure variation, while the economic performance of the unit will be deteriorated due to the deviation between the actual working characteristics and the design expectations of the LP casings.

Research and Application of Flow Path Retrofit Upgrade of the Subcritical 600 MW Turbine in Ninghai Power Plant

ZHANG Lei, ZHANG Junjie, FENG Liguo, QIAO Jiafei, XU Yatao

2018, 51(4):  89-95.  DOI: 10.11930/j.issn.1004-9649.201612028

Asbtract ( )   PDF (4314KB) ( )  

References | Related Articles | Metrics

In this paper, the research and application of flow path retrofit upgrade of the subcritical 600MW turbine in Ninghai Power Plant are introduced. Firstly, the performance and the existing problems of the subcritical 600 MW unit are analyzed, and the output status of the turbine before the upgrade is determined. Secondly, the achievements of the 300 MW steam turbine flow path retrofit upgrade projects in China and the guaranteed performance data from the manufacturers are studied; the thermal checking caluclation is conducted to get the expected performance index of the subcritical 600 MW steam turbine after the upgrade. Finally, the optimized design schemes, such as the cold end optimization and the final stage blade selection, are proposed after considering the upgrade schemes provided by the manufacturer to determinethe final scheme. With the flow path retrofit, the specific heat consumptionof the steam turbine is reduced by 332 kJ/(kW·h), and the economic benefit is remarkable.

Combustion Tuning Practice of DLN 2.0+ System for Heavy Duty Gas Turbine

HUANG Suhua, JING Di, ZHUANG Jie, FAN Hongwu

2018, 51(4):  96-100.  DOI: 10.11930/j.issn.1004-9649.201704039

Asbtract ( )   PDF (4215KB) ( )  

References | Related Articles | Metrics

In order to improve the operation and maintenance quality of the gas turbine, and master the regularity of its DLN combustion tuning, in this paper, the tuning rules are summarized through the practice with DLN 2.0+ system of the gas turbine. The study shows that the dynamic pressure fluctuation in each frequency band and the NO_x emission can be balanced by the adjustment of purge air quantity and the PM1 fuel ratio. When the content of NO₂ in the exhaust gas exceeds a certain concentration level during the gas turbine start-up, the visible "yellow plume" will appear. Through switching to the piloted premix mode as early as possible, and minimizing the fuel ratio of D5 and PM1, the impact of "yellow plume" during the gas turbine starting up process can be alleviated.

Study on the Influence of the Intervention of Wind Power on Steam Turbine Rotor Life

WANG Zhanzhou, CAO Lihua, WEI Honggang, YANG Ming

2018, 51(4):  101-107.  DOI: 10.11930/j.issn.1004-9649.201611094

Asbtract ( )   PDF (5281KB) ( )  

References | Related Articles | Metrics

In order to achieve the safe operation of wind and thermal power, this paper adopts the finite element method to analyze the load change of the thermal power unit, the temperature field and the stress field of the steam turbine rotor before and after wind power intervention. The dangerous position of the rotor is determined as well. Then the Mises Von stress curve of the rotor is plotted, and the total life loss of the steam turbine rotor is calculated based on the rain-flow counting method and the linear fatigue cumulative damage theory.The results show that whether the wind power is involved or not, the maximum value of Mises Von stress is always at the root of IP first stage impeller, and the temperature field also has severe change at the same location as well. When wind power is involved, the numbers of the stress cycle will increase so that, the life loss of the steam turbine rotor increasing from 0.000 653 9% to 0.001 408% and the life loss speed increasing 2.15 times as the original one., The study shows that wind power has significant influence on the rotor life.

Study on Off-Design Performance of Indirect Air-Cooling Steam Turbine Unit

LIU Xueliang, CHEN Shengli, WAN Chao, LI Gaochao

2018, 51(4):  108-114.  DOI: 10.11930/j.issn.1004-9649.201711151

Asbtract ( )   PDF (4587KB) ( )  

References | Related Articles | Metrics

Taking a 600-MW indirect air-cooling steam turbine unit for example, the calculation model of steam turbine, condenser and air-cooling tower is established on the basis of EBSILON software. Characteristics regarding to a variety of operation conditions are studied through the orthogonal test method, such that the variations of back pressure with respect to heat rate under the conditions of different ambient temperatures, circulating water flows and steam turbine loadings are obtained. The results show that, with constant circulating water flow and steam turbine load, as the ambient temperature goes up, the back pressure and the heat rate will keep rising. In particular the increasing rate in the high-temperature section is apparently higher than that in the low-temperature section. If the steam turbine load remains constant, the higher the ambient temperature, the higher the changing rate of the back pressure and the heat consumption rate under the same cyclic water flow. In the case of constant ambient temperature and the circulating water flow, with the raise of steam turbine load, the back pressure will increase while the heat rate will drop down. In the case of constant steam turbine load and circulating water flow, the rising rate of the outlet water temperature for the air-cooling tower is greater than that of the ambient temperature rise. Specifically, the former will be 1.11-1.15 times of the latter if the circulating water flow reaches full volume limit, which will lead to the rapid increase of the inlet water temperature at the condenser and the decline of the system economy performance.

Development and Application Overview of Electrostatic Precipitation Technology for Coal-fired Power Plant in China

AN Liansuo, WANG Jinping, LI Jianguo, YANG Haofeng, LIU Weiping, LIU Hanxiao, LI Zaishi, DU Yiqian

2018, 51(4):  115-123.  DOI: 10.11930/j.issn.1004-9649.201802039

Asbtract ( )   PDF (2317KB) ( )  

References | Related Articles | Metrics

The evolution of emission requirements and emission characteristics of dust from coal-fired power plants in China is described, the development history of electrostatic precipitation technology in coal-fired power plant is reviewed, the application of electrostatic precipitation technology is introduced, and its development trend is prospected. Since the independent research of electrostatic precipitation technology began in 1 960 s, China has already became one of the most dominating countries in the world after more than fifty years of development through the technology, digestion, absorption and re-innovation. The Ultra-low dust emission of coal-fired power plant and the main technology to fulfill the Ultra-low emission has attracted worldwide attention. The electrostatic precipitator has always been the main equipment for particle control in coal-fired power plants, which can meet the requirement of ultra-low emissionof 10 mg/m³ or 5 mg/m³. As for the high ash coal (A_ar>25%) unit, it is also possible and feasible to realize the concentration of particle emission lower than 5 mg/m³ through cooperating with wet desulfurization and dust precipitation. It is expected that the direction of dust precipitation technology will be energy saving, cooperative control, intelligence, standardization and internationalization in the future.

Diagnosis and Analysis on Ultra-low Emission Performance of Flue Gas Denitrification System for a 330 MW unit

MIAO Yongqi, LIU Haiqiu, ZHOU Kai, ZHUANG Ke, WU Bijun, JIN Dingqiang

2018, 51(4):  124-129.  DOI: 10.11930/j.issn.1004-9649.201707184

Asbtract ( )   PDF (8685KB) ( )  

References | Related Articles | Metrics

The anticipated target of NO_x emission control have not been reached in some power plants after the ultra-low emission retrofit project. To solve this problem, taking a 330 MW ultra-low emission unit as an example, onsite investigation was conducted and the operation data of a 15 500 h flue gas denitrification unit was collected. The operating catalyst was also sampled and tested. Besides, the causes of excessive NO_x emission were investigated individually. The research results show that the decline of denitrification efficiency is attributed to low design margin of SCR denitrification, low content of main active component V₂O₅ as well as the decrease of catalyst micropore number and active point number. In addition, the high NO_x concentration at the inlet of the reactor, the frequent load changes, and untimely ammonia spray response cause the NO_x emission at the outlet to exceed 50 mg/m³. In order to ensure that stable emission standards are met, it is suggested that the optimal operation of the boiler should be strengthened to avoid the large fluctuation of NO_x concentration and improve the response speed of ammonia injection. One extra layer of catalysts is also advised and the existing two layers of catalyst should be regenerated.

Theoretical Model for SO₃ Removal from Flue Gas Using Alkali Sorbent Injection Technology in Power Plant

YAO Xuan, YANG Jianhui, WANG Hongliang, DUAN Wei, SONG Peng, ZHANG Jun, LU Guangjie, ZHENG Peng

2018, 51(4):  130-135.  DOI: 10.11930/j.issn.1004-9649.201704102

Asbtract ( )   PDF (3242KB) ( )  

References | Related Articles | Metrics

Alkaline sorbent injection is a new technology to remove SO₃ from flue gas in power plant. In this paper, the technical features, system operation characteristics and principles of SO₃ removal using alkaline absorbent are introduced. Meanwhile, the theoretical model of SO₃ removal reaction is established and verified through practice. Moreover, the impact of alkaline sorbent on the activity of catalyst is examined. The results show that the terminal settling velocity of absorbent is 0.01~0.1m/s, which is far less than that of flue gas. By simplifying the gas-solid reaction model, the deviation of theoretical SO₃ removal efficiency from engineering measurement value is less than ±5%, and the SO₃ removal efficiency is related to the flue gas velocity, flue gas temperature, particle size, chemical equivalence ratio and so on. In the process of engineering design, in order to ensure the SO₃ removal efficiency above 80%, the stoichiometric ratio must be set higher than 1.5, and the particle size of absorbent must be smaller than 30 μm, while the retention time of absorbent particles should not be less than 4s. The side effects of sorbent sodium sulfite on denitration catalysts is negligible.

System Optimization and Economical Operation of the Series Absorption Tower

YANG Yonglong, SU Qiufeng, ZHANG Yang, WANG Jianfeng, WANG Renlei, HU Da, ZHU Yue

2018, 51(4):  136-142,179.  DOI: 10.11930/j.issn.1004-9649.201609047

Asbtract ( )   PDF (4581KB) ( )  

References | Related Articles | Metrics

Optimization tests of the series absorption tower are conducted in the work. The effect of the series absorption tower on different operating conditions is analyzed based on the optimization test results, and the best operation condition is selected. The results show that the desulfurization efficiency can reach over 99.2% using the series absorption tower. The suitable operation condition should be chosen in different load conditions accordingly to save the operation cost greatly, and the desulfurization effect of the series absorption tower fully meets the requirement of ultra-low emission.

Application and Performance Evaluation of Condensed Mist Eliminator in Desulphurization System

WANG Fengji, YOU Liangzhou, ZHU Yue, HU Da

2018, 51(4):  143-148.  DOI: 10.11930/j.issn.1004-9649.201704099

Asbtract ( )   PDF (3518KB) ( )  

References | Related Articles | Metrics

In order to realize the ultra-low emissions, a 600 MW coal-fired unit is retrofitted by replacing the original demister in desulphurization tower (two-stage roof type demister plus one-stage tubular demister) with the condensed mist eliminator. The condensed mist eliminator consists of three-stage ridge-type high-efficiency demister and condensed wet layer. In addition, a cooling station outside the tower composed of a spray cooling water pump and a closed cooling equipment is provided. The droplet emissions as well as overall collaborative efficiency of dust collection and SO₃ desulfurization efficiency of whole desulfurization system were tested under 50% and 100% working conditions respectively by adjusting the operating mode of outside cooling tower of the condensing demister. The test results show that the thermal capacity of the cooling station has significant influence on the operation performance of the condensing mist eliminator. Enhancing the heat transfer at the cooling station is helpful to improve the removal efficiency of droplet, dust and SO₃.

Research on Scale Problem of Single Tower with Dual Loop Desulfurization System

DONG Ruifeng, CHEN Haojun, WANG Fengtao, WU Wenlong

2018, 51(4):  149-154.  DOI: 10.11930/j.issn.1004-9649.201706032

Asbtract ( )   PDF (4271KB) ( )  

References | Related Articles | Metrics

Single tower with dual loop desulfurization system has been widely used in the retrofit of ultra-low emission. However, severe scale problem has taken place in the top slurry spray layer under the slurry collecting bowl in some coal-fired power plants with some nozzle and branch pipe of slurry spray layer also blocked. In this paper, two coal-fired power plants denoted by A and B are taken as examples. Through the examination of the on-site equipment and system, the analysis on the composition of scale sample in laboratory, and the numerical simulation on the flow field distribution of the desulfurization tower using CFD software, it is concluded that the scale problems are related to the size of slurry collecting bowl, nearby flow distribution, the volume of the slurry tank and pH of the slurry. In order to avoid the scale problem, starting from desulfurization tower design, operation parameters control and equipment maintenance should be enforced strictly. In power plant B, the one-way nozzles of the top slurry spray layer under the slurry collecting bowl had been replaced with two-way nozzles and the operation parameters have been also improved. Eventually, the scale problem of power plant B was solved successfully.

Application of CIM/SVG Data Exchange Techniques in Power Grid Alarming and Outage Planning System

PAN Qi, WU Feng, WANG Liang, CAO Zhikun, DONG Shufeng

2018, 51(4):  155-160.  DOI: 10.11930/j.issn.1004-9649.201701025

Asbtract ( )   PDF (2190KB) ( )  

References | Related Articles | Metrics

Data exchange techniques based on Common Information Model (CIM) and Scalable Vector Graphics (SVG) is useful in power grid alarming and outage planning system. This technical solution uses Java programming language and Apache Batik Toolkit as software development tool. Based on IEC 61970 CIM standard, power system data is modeled. CIM data is then visualized and operated via SVG-based user interface. This solution has been applied to practical power grid alarming and outage planning system.

Design of Remote Centralized Intelligent Monitoring System for Wind Farms

WU Tao, LIU Lihong, WANG Dailan

2018, 51(4):  161-167.  DOI: 10.11930/j.issn.1004-9649.201604141

Asbtract ( )   PDF (2333KB) ( )  

References | Related Articles | Metrics

To meet the operation requirement of unattended wind farms and to realize the integration of wind farms monitoring and management, a discussion is made on the design scheme of remote centralized intelligent monitoring system of wind farms. Based on the overall design requirements of the centralized monitoring system, a centralized monitoring system framework with open, layered and distributed architecture is proposed. A detail introduction is made to the data and voice communication between centralized monitoring systems and wind farms, wind power enterprise headquarters and power dispatch centers. The message-oriented middleware point-to-point transmission mode is used between centralized monitoring system and wind farms. Such function modules are designed as operation monitoring, intelligent analysis and diagnosis, and operation management. The advanced applications such as intelligent analysis and diagnosis are realized by using big data mining technology. The design scheme of centralized monitoring system can provide a good technical support for wind farm informatization and intelligence, and improve the operation, maintenance and management level of wind farms.

Selection Method Between Copper and Aluminum Power Cable by Life Cycle Cost

YOU Lei, ZHANG Xueying, WANG Pengyu, LI Feng, LIN Dong, LIU Gang

2018, 51(4):  168-174.  DOI: 10.11930/j.issn.1004-9649.201607043

Asbtract ( )   PDF (2231KB) ( )  

References | Related Articles | Metrics

Compared to copper power cable, purchase cost of aluminum power cable is much smaller, but technical performances are weaker in many aspects. In order to select between copper and aluminum power cable from long-term economic perspective, cable life cycle cost (LCC) model is established with consideration of time value of money. The model includes cost of purchase, installation, electricity loss, maintenance, failure loss and decommission. After calculation and comparison of LCC of two different cables, selection is made based on total LCC cost. Case study of cable line in Guangzhou urban area is performed. The results show that although purchase costs of aluminum cable are less than that of copper cable, the installation and operation costs of aluminum cable are much higher. Copper cable is better choice between two materials.

Direct-trading Modes of Large Consumers Participated by Charging Infrastructures Power Demand

FENG Yi, ZHANG Baoping, LIU Huiwen, YANG Lei

2018, 51(4):  175-179.  DOI: 10.11930/j.issn.1004-9649.201611023

Asbtract ( )   PDF (2145KB) ( )  

References | Related Articles | Metrics

With its rapid development, the electric vehicle charging business faces such problems as single profit mode and slow investment recovery. This paper discusses the feasibility of the power demand of charging facilities to participate in large consumers direct-trading and to accommodate the surplus renewable energies, such as wind power and photovoltaic power. And it also provides the ways and model for the power demand of charging facilities to participate in large consumers direct-trading, and estimates the profit space for the transaction. The provided model in this paper can not only reduce the electricity cost of electric vehicles, but also promote new energy utilization, subsequently realizing the coordinated development of energy industry and electric car industry.

Grid Enterprises Purchase Model Optimization Based on Integrated Cost

WANG Lei, XI Peiyu, SHI Shuhong, WANG Haining, WU Yujian

2018, 51(4):  180-184.  DOI: 10.11930/j.issn.1004-9649.201606003

Asbtract ( )   PDF (2052KB) ( )  

References | Related Articles | Metrics

The intensifies of greenhouse effect and environmental issues call for appropriate purchase strategies for power supply company to guarantee sustainable development of power industry. Negative environment effects caused by pollutant emissions during power production process are quantified as pollutant emission factors and governance cost. Those quantified indexes then converted to external environmental cost and integrated into purchase cost for purchase decision. A grid enterprises purchase optimization model based on integrated cost is established. Simulation results show that environmental protection effect is much higher than electricity purchasing cost increase with proposed model.