Electric Power

Study of the Effect of Rectifier Side Control Modes on UHVDC Commutation Failure

CHEN Shilong, RONG Junxiang, BI Guihong, LI Xingwang, CAO Ruirui

2015, 48(7): 1-7. DOI: 10.11930.2015.7.1

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Commutation failure in UHVDC transmission system causes sudden change of DC voltage and current and operation stability problems. As core part of UHVDC transmission system, control modes of control system has huge impact on system output. Based on commutation failure analysis, different rectifier side control modes are introduced. The simulation model of Yunnan-Guangdong UHVDC transmission system is built in order to study impacts of constant current control and constant power control on commutation failure in Yunnan-Guangdong UHVDC transmission system. The simulation results show that when rectifier side is under current control mode, the critical voltage ratio of inverter transformer threshold is greater than that of constant power control mode. Also, when rectifier side is under current control mode, the critical resistance value threshold is smaller than that of constant power control mode when three-phase grounding fault, two-phase short circuit fault or single-phase ground fault happens at inverter side AC bus. In summarization, as far as control ability for commutation failure is concerned, constant current control in the rectifier side is better than constant power control.

The Corona Control Study of Field Partial Discharge Test of UHVDC Converter Transformer

XIE Qijia, PU Ziheng, WANG Tao, ZHANG Yadong, DU Zhiye

2015, 48(7): 8-12. DOI: 10.11930.2015.7.8

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In order to study the corona control of UHVDC converter transformer field partial discharge test, a 3D model is established according to the test arrangement. The highest test potential is applied on the model and electric field distribution as well as maximum electric field strength on different test equipment are obtained by finite element analysis. The corona onset value is verified according to empirical formula and grading ball test in valve hall. The calculation results show that equipment design size has enough safety margin under field test scheme and meets corona control requirements of partial discharge test.

Analysis of Abnormal Switching Control Mode in Yunnan-Guangdong UHVDC Transmission System

PAN Zijun, XU Panteng, LIU Maotao, ZHANG Zhichao

2015, 48(7): 13-16. DOI: 10.11930.2015.7.13

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As key technique in HVDC transmission system, control system is extremely important to guarantee the realization of basic control strategy. The influence of DC current reference value on basic control mode in UHVDC transmission system is analyzed. According to recorded fault data during operation of Yunnan-Guangdong UHVDC Project, group block resulted from abnormal switching of basic control mode is analyzed in detail. Some practical measures including DC control system logic modification are proposed to improve system operation condition. It provides valuable reference for future implementation of UHVDC power transmission projects in China.

On-site Detection and Location of Partial Discharge in Ultra-High Voltage Convert Transformer

CHEN Ling, LIU Rui, LIU Fan

2015, 48(7): 17-21. DOI: 10.11930.2015.7.17

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An effective method to detect and locate partial discharge(PD) in convert transformer accurately is important when PD exceeds standard after installation. Using comprehensive method combined traditional method with emerging technology, the partial discharge in LYB convert transformer which installed in polar I of YIBIN convert station is located successfully. The online location gives an effective instruction to the default treatment. The result shows that combination of traditional electrical method and emerging technology such as ultrasonic and ultraviolet can enhance detection and location accuracy for PD in convert transformer.

Design of Belo Monte UHVDC Transmission Project in Brazil

CHENG Gaihong, YIN Weiyang

2015, 48(7): 22-26. DOI: 10.11930.2015.7.22

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Brazil has developed HVDC technology for a long time and accumulated rich experience in construction and operation of HVDC transmission project. Based on the HVDC development status quo in Brazil and the technical requirements in the concession auction document of the Belo Monte 800 kV UHVDC transmission project which is planned to be put into operation in 2018, an analysis is made for the project in terms of reliability, overload capacity, system losses and reactive power compensation allocation. Through comparison of the technical requirements of HVDC project in Brazil and in China, the design characteristics of HVDC project in Brazil are summarized under the private mode of power industry. Some suggestions are given for formulating the technical specification of the Belo Monte 800 kV project, which can also be a reference for design of HVDC project in China.

Fault Analysis of 800 kV UHVDC Wall Entrance Bushing

XIE Chao, HE Ping

2015, 48(7): 27-30. DOI: 10.11930.2015.7.27

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800 kV wall entrance bushing failures occurr frequently in ±800 kV Yun-Guang UHVDC power transmission system. Overhaul of 3 bushings indicates that different failures are resulted from same screw thread abrasion of locking ring connecting bushing outdoor and indoor parts. Metal dust produced by abrasion attached to casing short tail causes dielectric loss increment and insulation decrease which lead to current breakdown and grounding discharge. Thread abrasion also causes indoor and outdoor bushing connection fastening force decrease which characterized by resistance increment. Improved design of positioning pin including increased radial locking on bushing structure is proposed. Action to add resistance test in bushing preventive test procedures is also suggested.

Solution for Heat-Failure of Drainage Plate of ±800 kV UHV DC Transmission Line

LEI Dongyun, SHI Kai, NIU Jie, REN Chengxian, ZOU Dehua, MEI Wenjian, ZENG Wenyuan

2015, 48(7): 31-34. DOI: 10.11930.2015.7.31

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In order to eliminate the defect of the front #4 drainage plate of the ±800 kV Binjin transmission line’s #0585 pole I, live-line working safety are analyzed and working procedures are established. Soft ladder is used to enter strong electric field in order to fix defect on drainage plate. This is the first UHVDC live-line working in China.

Improvement Proposal of Converter Transformer Tap-Changer Control Circuit in Yunnan-Guangdong UHVDC Project

LIU Maotao, ZHANG Zhichao, YU Rongxing, XU Panteng

2015, 48(7): 35-38. DOI: 10.11930.2015.7.35

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Based on tripping incident caused by tap-changer control soource failure during commission of Yunnan-Guangdong HVDC project, control logic and impact of converter source failure are analyzed. The imbalance operationg risk of dual valve groups on same pole caused by incorrect tap changer operation is presented. A decoupled method is proposed to transmit different control signal seperately and to ensure reliable block or allow tap-changer adjustement. The proposed improvement is applied in Nuozhadu UHVDC project and reduced imbalance operation risk.

Analysis of Bipolar Block Caused by DC Line Fault and Flaw of Fault Recovery Logic in Chuxiong-Suidong UHVDC

WU Qianjin, ZHANG Nan, CAI Yongliang, WANG Xuezhi

2015, 48(7): 39-43. DOI: 10.11930.2015.7.39

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At AC/DC normal connected operation mode, there are two transmission line fault protection events on pole 1 and one event on pole 2 sequentially, which resulted to bipolar block. The protection operation rules on 87DCLL, WFPDL and DC line fault recovery monitoring function are investigated in order to reveal the reason of block. Electromagnetic coupling and bipolar grounding faults are analyzed with EMTDC simulation. Logic flaws in fault recovery monitoring function are revealed. Finally, suggestions are proposed to avoid unnecessary HVDC system block under fault condition.

Optimization and Function Test of Feed Water RB Control Strategy for a 600-MW Supercritical CFB Unit

LEI Xiujian, WU Yuping, CHEN Feng, GAO Mingming

2015, 48(7): 44-47. DOI: 10.11930.2015.7.44

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This paper analyzes the dynamic characteristics and control of feed water run back(RB) of a 600-MW supercritical CFB once- through boiler and proposes the optimal RB control strategy for this boiler. In addition, it presents the scheme and process of the RB functional test. The results will provide reference for the reliable use of feed water RB function on supercritical CFB boilers.

Remote Monitoring and Diagnosis Platform of Power Generating Equipment for Power Grid Security and Stability

LUO Jia, ZHOU Yi, WANG Jianjun, XIAO Xiaoqing, SONG Weiqiao

2015, 48(7): 48-53. DOI: 10.11930.2015.7.48

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The remote monitoring and diagnosing of power generating equipment can be carried out in time by experts through the real-time transmission of operation information from power generation enterprises to power research institutes. In this paper, the overall technical solution is presented for constructing a remote monitoring and diagnosis platform system for power generation equipment in the group company coverage. The system functions consist of data integration, online monitoring and diagnostic analysis. The mass remote data is transferred with encryption and compression technologies. The system architecture adopting hierarchical components and modularized applications is built based on the SOA standard, and the problem of using mass heterogeneous data is solved by a data adapter interface built with the common information modeling technology. Therefore, the remote monitoring and diagnosis of power generating equipment such as boilers, turbines and generators, are accomplished through soft measurement and diagnosis technologies based on the working mechanism of the equipment and intelligent real-time data mining technologies. The application of the demonstration project indicates that the overall technical solution and the system architecture presented in this paper are correct and reasonable, and they are helpful in improving the security and stability of power grid operation.

Pilot Experiments on Large-Scale Low Temperature Multi-Effect Distillation Desalination

ZHANG Zhongmei, ZHANG Jianli, LI Yanbing, DING Tao, YANG Qingwei

2015, 48(7): 54-58. DOI: 10.11930.2015.7.54

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In order to provide technical instructions on the structure design and technical process optimization of large desalination equipment, based on the pilot experiments of large-scale low temperature multi-effect distillation desalination(LT-MED), the effects of different parameters on the performance of the desalination equipment are studied, such as the motive steam and suction steam pressure of thermal vapor compressor (TVC), the evaporating temperature, the flow rate of seawater spray and the steam preheater. The results show that the TVC suction flow rate increases linearly with the growth of suction steam pressure. Also the gained output ratio(GOR) and freshwater production can be improved by increasing the evaporation temperature and proper seawater spray density as well as adopting steam preheaters.

Cause Analysis and Treatment of Sulfur Corrosion in Transformer Oil in a Power Plant

WANG Juan, WANG Xiaowei, YANG Jinxing, SHAO Wei

2015, 48(7): 59-62. DOI: 10.11930.2015.7.59

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The breakdown voltages of transformer oil in Main Transformers 1 and 2 are low and their total hydrocarbon contents are continuously increasing. Therefore, a series of tests are performed to figure out the reasons. The tests include SEM, elemental analysis, X-ray diffraction analysis and corrosive sulfur tests. The results show that the total sulfur and corrosive sulfur contents in the oil are high, which causes sulfur corrosion, and a reaction of the sulfur-containing substance with winding material takes place, producing the Cu2S and Cu4SO4(OH)6, which affects the transformer’s insulating function and leads to the increasing of g the hydrocarbon contents. Recycling treatment and passivator adding to the oil can reduce the contents of total and corrosive sulfur and alleviate copper corrosion by sulfur.

Experimental Study on Flue Gas Water Recovery Performance Using Composite Membranes in Thermal Power Plants

CHEN Haiping, ZHONG Yajuan, ZHOU Yanan, LAN Junjie, DU Wentao

2015, 48(7): 63-67. DOI: 10.11930.2015.7.63

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Water recovery by composite membranes from flue gas is expected to be an effective technology for water saving in thermal power plants. In this study, the SPEEK-PES hollow fiber composite membrane is made by using polyether sulfone (PES) as the hollow fiber membrane support layer material and sulfonated polyether ether ketone (SPEEK) as the coating material for the hollow fiber membrane; the effect of different sulfonation degrees of SPEEK coating, purge gas flow rate and flue gas temperature on the water capture performance of hollow fiber composite membrane is studied with the simulated flue gas(H2O/N2). The experimental results show that higher sulfonation degree of SPEEK of the composite membrane does not mean better; the purge gas flow rate also has an optimal value; in the range of experimental temperatures(40~70 ℃), with the temperature increasing, the water capture performance of the composite membrane improves.

Restoration of Main Valve Seat of HP Bypass in a Coal-Fired USC Power Unit

TANG Bin, LU Ya’an, LU Yaowei, CAI Baogen

2015, 48(7): 68-71. DOI: 10.11930.2015.7.68

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In this paper, the restoration of main valve seat of HP bypass pipes in a 1 000-MW coal-fired USC power unit is introduced in detail. Through implementing strict restoration procedure and adopting hot-wire arc welding and nickel-base superalloy as transition material, as well as the flexible robotic welding arms with six-aixs simultaneous motion the problem of surfacing in tight spaces, such as the main valve chamber of HP bypass pipes under high-temperature harsh environmental conditions is tackled, which ensures the quality of surfacing layer to meet the performance requirements of valve seat sealing surface. Meanwhile, the defects such as cracking and blowing loss on the steam valve seat of HP bypass pipes which is built with SA184-F91/F92 are solved completely. Therefore, the reliability and economic efficiency of the power unit are guaranteed. This restoration can provide ideas and methods for solving steam valve leakage under high steam temperature and pressure in coal-fired USC power units.

Retrofit Design and Control of 600-MW Unit Heating System

XU Ruifeng, ZHAO Junying, ZHANG Donghai

2015, 48(7): 72-75. DOI: 10.11930.2015.7.72

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In order to eliminate the potential safety problems which may endanger system operation of conventional thermal power units after heating system retrofit, by taking the heating system retrofit of a 600-MW unit of a power plant for example, the design characteristics such as the medium-pressure section exhaust steam and low-temperature reheat pipe extraction and the condenser water inlet system are presented. Through the analysis on the design principle of the thermal system and its heating operation mode, it is concluded that problems, such as over-current, over-voltage and overheating of blades, turbine overspeed and condenser water replenishment tend to arise after heating system retrofit. Therefore, the factors affecting the equipment safety are clarified. In addition, the effective control and protective measures are also put forward to avoid heating system accidents, ensure the safe operation of the unit, and achieve heat and power cogeneration.

Research on Transmission Network Planning Model Based on Risk Cost under Market Environment

LOU Suhua, WANG Yajuan, LU Siyu, WU Yaowu

2015, 48(7): 76-81. DOI: 10.11930.2015.7.76

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Under the market economy, more attention is paid to the economic efficiency of power grid investment by the power utility company. In this paper, a novel transmission network planning model is proposed with consideration of the risk cost, in which the equivalent annual value of investment, the operating cost and the minimum overload risk of system operation are taken as the objective functions. The imperative constraint condition, which is represented by “N-1” constraint in conventional model, is replaced by the overload risk cost of power system. Accordingly, the transmission company can make a compromise between the reliability and economics. In order to obtain the overload risk cost, an overload risk evaluation formula is given by calculating the minimal the economic cost of load shedding in case of the single failure of transmission network. Case studies on a Garve 6-bus system demonstrate the effectiveness of the proposed model.

Correlation Analysis and Forecast on Industrial Electricity Demands Based on Seasonal Divisions

MA Rui, PENG Zhou, JIANG Shiyao, XU Huiming, WANG Xiliang

2015, 48(7): 82-88. DOI: 10.11930.2015.7.82

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The forecasting of industrial electricity demand has a vital significance for realizing the refined power consumption management and reducing the cost of electric power enterprises operation and planning. However, the conventional forecasting methods, which forecast the electricity demands in the medium-term under the division of industrial structure, can’t provide satisfied results. In this paper, the correlative relationship between industrial electricity demands and forecasting methods is analyzed according to different seasons, and the external influence of temperature is discussed. In addition, on the basis of the aforementioned analysis and the econometrics theory, an error correction model is established in seasonal divisions for forecasting electricity demand. Finally, the monthly electricity demands of one province in the central China is forecasted and analyzed by using the correction model, and the results proves the feasibility of the method and shows the promised accuracy.

ind Power Feed-in Tariff Pricing Mechanism Based on Wind Power Cost and Thermal Power Profit

LIU Jizhen, LIU Tao, CUI Chao

2015, 48(7): 89-94. DOI: 10.11930.2015.7.89

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The current sub-regional fixed feed-in tariff system of wind power does not reflect the cost change of wind power, which causes the waste of state finance funds. Furthermore, the specific accounting process of wind power cost and reasonable profit is not given by the system, and the fixed feed-in tariff is not so rational. So a wind power feed-in tariff mechanism based on wind power cost and thermal power profit is put forward. Then the implementation process of the pricing mechanism is introduced through the case study of a thermal power plant and a wind power farm and the rationality of the pricing mechanism is testified.

Economic Analysis of Optimal Allocation of Fast Cut Back Thermal Power Units

LIU Haoming, NING Jian, WU Jianchao, LU En

2015, 48(7): 95-100. DOI: 10.11930.2015.7.95

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Fast Cut Back (FCB) thermal power units can be used as blackstart units to boot up power system restoration. The key technology for realizing FCB function is discussed in the paper. Besides, the related costs, in terms of the cost of achieving FCB function and the cost of using FCB function, are also estimated. With consideration of the reduced outage cost brought by FCB units, an economic indicator function is built to calculate the economically-optimum allocation of FCB units, and an economic analysis is carried out through case study of an IEEE-118 power system and a power grid in Guangdong province. The result can provide a reference for reasonable allocation of FCB units in the practical power grids.

Study on CCS Investment Decision-making Based on Real Options for Coal-fired Power Plant

WANG Xiping, DU Lei

2015, 48(7): 101-107. DOI: 10.11930.2015.7.101

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Based on the theory of real options, this paper establishes a quad-tree model that can be used to evaluate the CCS investment of coal-fired power plant. The proposed model considers four uncertain factors, including carbon prices, fossil fuel prices, investment cost and government subsidies. The solving steps of the proposed model are illustrated with an example in the paper. The results validate the preciseness of the real options approach compared with the conventional NPV method. Then, the influence of different government subsidy coefficients on decision-making is analyzed, and the critical carbon price under different government subsidies for CCS investment is calculated. The results show that the government subsidies affect the value of investment option and the optimal investment timing. It is suggested that the coal-fired power plant should ignore the subsides in current market conditions and not be invested before 2021. The conclusion provides a theoretical foundation for the CCS investment of coal-fired power plant.

Development of Distributed Cogeneration System in Japan and the Revelation to China

REN Hongbo, WU Qiong, YANG Xiu, GAO Weijun

2015, 48(7): 108-119. DOI: 10.11930.2015.7.108

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The development history of cogeneration system in Japan and measures adopted during different development stages are discussed in detail. In addition, current situation and development trend of cogeneration related software and hardware technologies are analyzed. Furthermore, the subsidies and preferential policies for encouraging cogeneration system in Japan are summarized. Finally, with consideration of China’s actual conditions, some ideas and suggestions are proposed from technical, financial and political viewpoints for application and expansion of cogeneration system in China.

Test Study on pH Value and Liquid Level of Absorption Tower in Desulfurization Efficiency Improvement

LAN Minxing

2015, 48(7): 115-123. DOI: 10.11930.2015.7.115

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In order to study the contribution of pH value and liquid level to the desulfurization efficiency in the bubbling absorption tower, tests have been conducted on Unit 4 in Taishan Power Plant. The tests on pH value conclude that under the condition of 600-MW load and with the liquid level being stabilized at about 220 mm, the desulfurization efficiency is improved from 93.78% to 96.78% with the pH value increasing from 4.6 to 5.6, while the SO2 emission concentration reduces from 119 mg/m3(dry, 6%O2) to 31 mg/m3(dry, 6%O2), showing a significant effect on desulfurization improvement. Besides, the tests on the liquid level conclude that when the load is maintained over 600 MW and the pH value is stabilized at about 4.6, the desulfurization efficiency is raised from 94.41% to 96.81% with the liquid level increasing from 210 mm to 330 mm, and at the same time, the SO2 emission concentration drops from 87 mg/m3 to 44 mg/m3. The results of these tests exhibit that the contribution of pH value is greater than that of the liquid level to the desulfurization efficiency improvement

Retrofit of Flue Gas Monitoring and Denitration Automatic Control Systems in a Power Plant

WANG Qiwei

2015, 48(7): 120-114. DOI: 10.11930.2015.7.120

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Taking the 600 MW domestically-made supercritical unit of a power plant as an example, the common existing faults in the continuous monitoring system for the desulfurization and denitriation equipments is analyzed and the corresponding preventive measures are put forward. The implementation of these preventive measures has effectively improved the accuracy of SO2, NOx, gas dust and gas flow measurement. In addition, the numerical simulation is carried out on the unevenness of the exit sectional NOx concentration during the denitration process to optimize the original design. Based on the simulation result, the ammonia injection control system is modified such that, the denitration efficiency is improved and the NH3 escape rate is now under control.

Operating Characteristics of Mist Eliminator in Desulfurization Spray Tower

HE Yangpeng, TAO Ming, SHI Zhenjing, GUO Haoran, HE Yudong

2015, 48(7): 124-128. DOI: 10.11930.2015.7.124

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The performance of mist eliminator(ME) is of great significance for stable desulfurization system operation, flue corrosion and gas emissions. Therefore, it is necessary to study the ME performance under different empty tower gas velocities and other combinations. In this paper, a test spray tower similar to actual projects is established to explore the effects of gas velocity, the space between the spraying layer and ME, and atomizing nozzle on the droplet contents of ME outlet and droplet size distribution, as well as the performance of pipe-type ME. The result shows that the gas velocity has great influence on the droplet contents of the first ME outlet and some effects on that of the second ME outlet. The droplet size decreases with the gas velocity increasing. The droplet contents of the first ME outlet increase significantly when the spray particle turns small, and they are greatly influenced by the space between the spraying layer and ME. The pipe-type ME has little effect on the outlet droplet contents.

Simulation Analysis of Desulfurization and Denitration based on the Method of Ozone Combined with Wet Calcium Based Scrubbing

ZHANG Xiang, YANG Li, JIANG Hong, WANG Zhihua, ZHOU Junhu

2015, 48(7): 129-133. DOI: 10.11930.2015.7.129

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To explore the removal effect of high nitrogen oxides on wet calcium based desulfurization system, the reaction mechanism and absorption properties of NO2 and SO2 simultaneous absorption by CaSO3 is conducted based on the point of thermodynamics and kinetics. The computing approach of absorption reaction is established and the effect of pH value on mass transfer rate is analyzed. By adopting this approach, the critical ratio of absorbed gas volume to solution volume is calculated, and the mass transfer rate is simulated in Na2SO3 and CaSO3 solutions with different NO2 gas partial pressures. The simulation results are verified against the testing results, which exhibit great consistency. According to the computing and testing results, the absorption rate of NO2 in Na2SO3 solution declines with the decrease of pH value, while no obvious change in CaSO3 solution is observed. These results can provide reference for the development and industrial application of ozone method combined with wet calcium based scrubbing.

Study on the Influence of Flame Height on Gap Breakdown Characteristics of Transmission Lines

CHEN Xiaoming, WEI Han, RUAN Ling, HUANG Daochun, HUANG Junjie, LI Peng, XIONG Yu,RUAN Jiangjun, ZHANG Yafei, QIN Zhihang

2015, 48(7): 134-138. DOI: 10.11930.2015.7.134

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Forest fires can make the gap insulation strength of overhead transmission lines decrease significantly, which may cause transmission-line tripping and lead to serious power outage accidents. In recent years, frequent forest fires have brought a great threat to the safety of the power grid. In this paper, wood-chock fire is used to study the influence of flame height on the gap breakdown characteristics of transmission lines. The simulated results show that the flame height has a significant effect on the gap breakdown characteristics and the flame height and breakdown voltage have a relationship of quadratic function, which can provide an useful guidance for tripping prevention of transmission lines in case of forest fires.

Analysis on the Dynamic Responses of Tower-line System of 500 kV Transmission Line with Galloping Conductors

YANG Fengli, DANG Huixue, YANG Jingbo, LI Xinmin

2015, 48(7): 139-145. DOI: 10.11930.2015.7.139

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In this paper, a FEA model of continuous five-span tower-line system is established firstly. With different damping coefficients, the aerodynamic analysis method is applied to obtain several parameters of conductors, including conductor tensions, unbalanced tensions and galloping traces. The dynamic responses of the towers under galloping load are then analyzed. It shows that the dynamic responses calculated with the tower damping coefficient are higher than that with the conductor damping coefficient. With consideration of the tower-line coupling effect, the galloping amplitudes increase, and the conductor tensions as well as the unbalanced tensions decrease. The vertical motion of the galloping conductor changes from multi-order vibration of two-principal frequency to the first order vibration with one principal frequency. When analyzed with the tower coefficient, the unbalanced tension exceeds the designed broken tension and the stress of the diagonal member at the bottom plane of the cross arm is higher than the designed stress, which shows that the cross arm will be collapsed.

Characteristics of Airflow over Typical Micro-Terrain and Its Application to Design of Overhead Transmission and Distribution Lines

GAO Yan, YANG Jingbo

2015, 48(7): 146-152. DOI: 10.11930.2015.7.146

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Provisions are given on the calculation of wind speed over complex terrain in the load code of China. However, the actual micro-terrian varies significantly from place to place and a big difference appears sometimes between the actual wind speed and the design value, which leads to the broken of overhead transmission and distribution lines and towers from time to time. Thus, it is necessary to investigate the design method of the transmission line under micro-terrian conditions. A simulation analysis is conducted on airflow characters in different micro-terrian settings, namely hills, cliffs and saddle backs. A formula is deduced for calculating the wind speed correction coefficient under typical micro-terrain settings and its application conditions are also provided. Finally, a model of two-tower and a line is established to testify the influences of different micro-terrains on the overhead transmission lines under gale wind. The result shows that the obtained formula is applicable for the overhead transmission line design and checking.

Research on Parallel Gap Burn of Ground Wire Insulator for 500 kV Transmission Lines

FANG Yuqun, XU Feiming, GU Hao, LIANG Jiakai, SUN Guangxu, XING Zheming

2015, 48(7): 153-160. DOI: 10.11930.2015.7.153

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In view of the parallel gap burn problem of ground wire insulator for 500 kV transmission lines, a systematic analysis indicates that the wrong grounding mode of ground wire insulator, which leads to the complete insulation of the strain section, is the principal reason for the parallel gap burn, and the unreasonable structure of ground wire insulator gap is another important reason. In this paper, a quantitative study has been carried out on all the grounding modes of 500 kV transmission line under different operating conditions. The induced current, induced voltage and induced energy are simulated and calculated under different grounding modes of ground wire, and the reasons for the parallel gap burn problem are further quantitatively determined. Finally, based on the simulation results and engineering practices, an improved scheme is proposed for the parallel gap of ground wire insulators.

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