01 August 2014, Volume 35 Issue 8

    

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  A Capacitor Voltage Dynamic Balancing Method for Multilevel Converters Based on Taking Power from Capacitors

  WEI Yingdong, ZHANG Chunpeng, YU Xinyu, JIANG Qirong

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 1-5. https://doi.org/10.3969/j.issn.1000-7229.2014.08.001

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  The capacitor voltage balancing problem of multilevel converters may result in the reduction of capacity utilization, the unstable operation and the deterioration of power quality. Based on taking power from capacitor, a dynamic resistance balancing device for multilevel converters and its control method were proposed, in which the dynamic equalizing resistance consisted of a low-voltage MOSFET and a resistance in series, and the power was taken from the capacitor through a DC-DC convertor with wide range voltage input. The turn on/off of low-voltage MOSFET was controlled by hysteresis comparison method or duty ratio control method, which could implement the dynamic balance control of multilevel converter's capacitor voltage. The increased cost of the device is very low, the control method is simple and easy to implement； it has strong universality and can be applied in all kinds of multilevel converters. Based on PSCAD/ EMTDC, the results show that the proposed dynamic resistance balancing device and control method can well realize the dynamic balancing control for the capacitor voltage of multilevel converter.
  
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  Control Strategy and Experimental Study of Hybrid HVDC Circuit Breaker

  DU Yi, JIANG Daozhuo, CHEN Ke, WANG Yufen, YIN Rui, ZHANG Chi

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 6-11. https://doi.org/10.3969/j.issn.1000-7229.2014.08.002

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  Existing HVDC circuit breakers are capable of interrupting HVDC currents within several tens of milliseconds, but this is too slow to fulfill the requirements of a reliable HVDC grid. HVDC breakers based on semiconductors can easily overcome the limitations of operating speed, but need large number of the series （parallel） connection of electronic switching devices； at the same time, it requires high technology and generates a lot of loss. To overcome these shortcomings, a topology of hybrid HVDC circuit breaker was introduced. Firstly, this paper described the principle of hybrid HVDC circuit breaker； then a control strategy of fault pretreatment was also proposed, that was the pre-action of the converter when fault occurred, in order to improve the breaking speed of the hybrid circuit breaker； at last the modeling and simulation were carried out on the hybrid HVDC circuit breaker by PSCAD, and unit prototype was made for the step-down experiments. The simulation and experimental results prove that: when a short circuit occurs, the hybrid HVDC circuit breaker can quickly break the short-circuit current| and the buffer circuit can be provided for the release of the stored energy circuit in DC circuit and load.
  
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  Evaluation Indices Set Construction of Security Requirement for Transmission Network

  HUANG Wenying, DENG Zhaoyun, DENG Yong, HE Guangyu, CHEN Rui, LIU Kaicheng

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 12-17. https://doi.org/10.3969/j.issn.1000-7229.2014.08.003

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  The core requirement of transmission network enterprise lies in the safe operation of transmission network. Failure in satisfying this requirement will result in disastrous loss on economic and social benefits. Hence, transmission network is expected to possess the capability of enduring possible disturbances in order to ensure the normal operation of grid and equipment, as well as avoid the power transmission interruptions. Through the analysis on the requirement satisfaction of transmission system stakeholders, the overall status of transmission network operation can be evaluated. Based on the stochastic characteristics of transmission network operation, this paper used a risk assessment method to construct evaluation indices set for the security requirement, and proposed the calculation model and method of security risk assessment indicators. Compared with the traditional researches on grid security, a scenario analysis approach was introduced. In detail, breakdown or normal operation of certain components under certain specific operating modes was modeled as a scenario, and a probabilistic model for the scenario was constructed with taking into consideration a variety of random factors. All kinds of security problems were studied in the specific scenarios. The security of the situations could be evaluated comprehensively according to the safety criterion indices； therefore a minimum expense of control could be adopted to measure the consequence of the disturbance on the transmission network operation. Through sampling method, the probability and consequence of each situation occurrence could be acquired； and with the assistance of calculating value at risk and conditional value-at-risk, the security risk of transmission network could be evaluated properly.
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  Implementation of Transmission Network Operation Evaluation System in Fujian Power Grid

  LIU Kaicheng, HE Guangyu, CHEN Rui, HUANG Wenying, DENG Zhaoyun, DENG Yong

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 18-23. https://doi.org/10.3969/j.issn.1000-7229.2014.08.004

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  For the better application of the index system in the operation practice of power grid, the implementation method of online operational analysis and aided-decision system （OOAADS） was introduced in detail from three aspects: index selection, hardware architecture and software architecture, based on the index system for the transmission operational evaluation proposed by the authors and the actual condition of Fujian power grid. Firstly, combined with the actual requirements of Fujian power grid, the index that should be used in the OOAADS was chosen from aspects of results evaluation and reasons evaluation. Secondly, the hardware composition of system server and its function allocation, the software architecture and its key technologies were introduced. Lastly, this paper described the process of eliminating event of the OOAADS in two typical out-of-limit cases occurred in the practical operation of the transmission grid. The results show that the OOAADS is feasible and effective for evaluating the running state of power grid and providing aided-decision, which is helpful to guide the operation practice of power system.
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  Study on Power Grid Blackout Risk under Different Connection Modes

  LIU Zifa, GUO Huimeng, LI Mengyu

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 24-31. https://doi.org/10.3969/j.issn.1000-7229.2014.08.005

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  As the interconnection of our country's power system becomes more and more stronger, it is an important problem to make assessment of the reasonable grid construction scale. The purpose of this study is evaluating the construction scale of power grid by calculating the blackout risk under different scales of the grid. From the view of blackout risk, the risk assessment index system and risk assessment models about various wire connection were established in this study to evaluate the rationality of grid construction scale. And the IEEE-14 bus system was used to verify the validity of the model. In the last, the assessment theory and models were applied to a particular ultra high voltage （UHV） synchronous power grid to demonstrate its reasonable construction scale in the blackout risk perspective. Research shows that the number of the large transmission line and the length of the transmission line are in the reasonable range. This method has practical value in engineering.
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  Adaptability Evaluation Content and Indexes for Large Power Grid Construction

  LIU Lianguang, CHEN Yanwei, WANG Zhidong, MA Chenglian

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 32-37. https://doi.org/10.3969/j.issn.1000-7229.2014.08.006

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  With the deepening of electricity market reform and the development of community economy, as well as the increasing of grid scale, researching and establishing the adaptability evaluation theory and method of power grid construction not only are realistic demand, but also have great influence on improving the evaluation theory and method of power grid planning. The adaptability evaluation contents for large power grid construction consisted of the adaptability of the national economy, the adaptability of energy structure, the adaptability of grid structure and the adaptability of technology development. This paper also discussed the constructing theory and practice basis of the evaluation contents； put forward eighteen evaluation indexes, such as electricity balance coefficient, capacity-load ratio, etc.； and presented the calculation methods of the indexes.
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  Fault Characteristics and Recovery Strategy of Capacitor Commutated Converter （CCC） HVDC Transmission System

  LIU Yao, XIE Chenxi，LI Xinnian，WANG Jingfang，WANG Huawei

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 38-42. https://doi.org/10.3969/j.issn.1000-7229.2014.08.007

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  This paper studied the fault characteristics of the inverter side of capacitor commutated converter （CCC） and the strategy, principle and operation time of the follow-up fault after avoiding a short single-phase fault. Based on the series compensation technology of HV lines in AC system, the defect that it was difficult to be resolved after the inverter side fault of CCC in DC transmission system was resolved successfully, by using the strategy of 'bypass breakers' for the first time. The feasibility of the strategy was verified through the simulation. The research results have great significance for the improvement of the dynamic characteristics of CCC HVDC transmission system and its further development.
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  Comparation on Wind Power Collection Capacity of Meshed and Radial Grids

  LIU Lianguang, HAN Longyan, JIANG Zhihua, LIU Zifa

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 43-48. https://doi.org/10.3969/j.issn.1000-7229.2014.08.008

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  For great number of wind turbines and large wind power of centralized wind farms, 10 kV or 35 kV meshed grids were proposed to build power collection grids of wind farms, in order to improve the reliability of power collection grids. The topology of meshed power collection grid and its outage rate evaluation model were established, and the outage rate evaluation index of both meshed and radial power collection grids were calculated. The outage simulation models of the two power collection grids were built on MATLAB / Simulink software platform, and the current level and voltage level of collecting bus before and after the fault being cut off in the two grids were analyzed, and the power collection capacity of meshed power collection grid for wind farm was studied, and the cable investment and power income of the two grids were compared. The results show that the equivalent expected energy not supplied（EENS） of radial power collection grid is 4.6 times as much as that of meshed power collection grid, and the total income of meshed power collection grid is 0.612 million RMB more than that of radial power collection grid, and meshed power collection grid is better at collecting wind farm power and smoothly sending out wind farm power than radial power collection grid, and meshed power collection grid has good investment prospects.
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  Integration Platform of Power Network Planning and Design

  MIAO Peiqing, LI Yue, HUANG Wei, WANG Yu

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 49-53. https://doi.org/10.3969/j.issn.1000-7229.2014.08.009

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  In order to realize the efficiency and scientificity of power network planning and design, a unified data center for power network planning and design should be established. Based on the electricity information management system, supervisory control and data acquisition, power production management information system, the data of power grid GIS and the visualization technology of CAD, unified planning platform of State Grid were fused, as well as the existing simulation analysis tools of power network was integrated. The visual and guided integration platform with planning research, engineering feasibility study, technological assessment and economic analysis was developed for power network planning and design, which could realize automatic power grid planning, schedule automatic sorting, preparation and evaluation system of planning and design. It can realize the efficiency and scientificity of power network planning and design, and improve the unified management and utilization efficiency of planning results.
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  Application of 220 kV Directly Step-down to 10 kV Power Supply Mode in Liaoning Power Grid

  NING Liaoyi, WU Zhuohang, QUAN Chenghao, SHEN Fang, LIU Jian, HU Dalong, SONG Yingwei, LIU Yan

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 54-61. https://doi.org/10.3969/j.issn.1000-7229.2014.08.010

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  In order to solve the difficulty land requisition and high land cost problems for substation and line corridor in high load density regions, this paper put forward a scheme of 220 kV directly step-down to 10 kV to reduce the construction land of power facilities and save the cost of construction. According to the actual situations of power grid in Liaoning, this paper built two kinds of power supply models for 220/10 kV and 220/66/10 kV voltage sequences, and analyzed the technical and economic indicators, including the construction scale, the occupied area, the power supply cost of unit load and the terminal voltage deviation rate of 10 kV line. The results show that the 220/10 kV directly step-down to 10 kV scheme used in urban load center with load density higher than 15MW/km2 can attain better economic benefit. It is suggested that the area selection for directly step-down substation should think over four aspects: the capacity requirements of main transformer, easily 220 kV power supply, no requirement for 66 kV network, and high demand for 10 kV network.
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  Numerical Simulation Analysis of Load Cable for Cargo Cableway of Overhead Line

  NIU Yonghua, WANG Zhihua, XIA Shunjun

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 62-66. https://doi.org/10.3969/j.issn.1000-7229.2014.08.011

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  The cargo cableway for overhead transmission line is usually used in high mountains and region with great topographic relief. So the parameters and tensions of load cable sections are usually quite complicated and changeable during the installation of cargo cableway. The calculation of the parameters and tensions of load cable with load has important significance to the improvement of the safety and economy of cargo cableway. When the span of the load cable was large enough, the continuous load cable could be simplified to multi-span catenary equations set, and the fulcrum friction coefficient of load cable of cargo cableway could be assumed as zero. Then the level tensions and loading point elevations in every span was set as adjustable cells with using the Programming Function of Microsoft Excel. Based on the constraint conditions: tension-balance in each span fulcrum, line length balance with load and non-load, balance between vertical component of bearing cable tension and total load in loading point, the changes of the parameters and tensions of load cable sections were calculated rapidly. The model, whose calculation results are identical with the actual measured data, can be applied for practical constructions.
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  New Double-Column Transposition Tower for 1 000 kV UHVAC Power Transmission Line

  PAN Shaocheng, FANG Xiaoming, LIU Zhaokang, LI Zeng

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 67-71. https://doi.org/10.3969/j.issn.1000-7229.2014.08.012

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  As the transposition design of 1 000 kV UHVAC double-circuit transmission line was complicated, the advantages and disadvantages of three-column transposition tower were analyzed. According to the disadvantages of three-column transposition tower, which were more occupied land, complicated jumpers and high construction requirements, a new type of tower named double-column transposition tower was researched. The jumpers' arrangement, electromagnetic environment, lightning protection level, jumper fitting strings' design of double-column transposition tower were introduced. Compared with the three-column transposition tower in corridor area, tower weight and other comprehensive economic indicators, it shows that double-column transposition tower has more superiority and practicability.
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  Accurate Calculation Method for Neutral Reactor of EHV Double-Circuit Line

  ZHANG Jiankang, LIN Jingyun, LIN Jun

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 72-76. https://doi.org/10.3969/j.issn.1000-7229.2014.08.013

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  To solve the accurate calculation problem of secondary arc current and recovery voltage in non-complete-phase operation after single-phase grounding fault of double-circuit line with shunt reactor and neutral reactor, this paper used eigen-model decomposition method to decouple zero sequence parameter in double-circuit line, and proposed the formula for non-complete-phase operation of double-circuit line based on its measured parameters: positive/negative sequence impedance, electrical susceptance, zero sequence self-impedance and mutual impedance, zero sequence self-susceptance and mutual susceptance. The results show that the calculation result of secondary arc current and recovery voltage at fault point can provide a reliable basis for the parameter determination of neutral reactor in double-circuit line, which is valuable to engineering application.
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  Electromagnetic Compatibility Influence of Low Voltage Power Line Carrier Communication and Motor-Driven Household Appliances

  XU Zhongpu, WANG Xuewei, LI Jianqi, TIAN Haiting

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 77-83. https://doi.org/10.3969/j.issn.1000-7229.2014.08.014

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  To solve the problems of household appliances being affected by low voltage power line carrier communication （LV-PLC）, through the combine of mechanism analysis and experimental verification, this paper carried out the study on the electromagnetic compatibility influence of carrier communication and motor-driven household appliances for the first time. Firstly, the send and receive model of LV-PLC signal were established； secondly, the carrier model of single-phase asynchronous motor was proposed and the influence of carrier on its performance was analyzed. Then, the common-mode and differential-mode experimental systems and methods for the influence of LV-PLC on the electromagnetic compatibility of motor-driven household appliances in the laboratory were designed, and four typical household appliances were selected and tested. It is concluded that: the line's voltage, current, output power, power factor and other parameters will be impacted to some extent by high-frequency carrier signal, when the motor-driven household appliances access the line, but these influences will not result in electrical performance degradation or loss of function. Finally, the influence analysis was carried out on the reliability of motor-driven household appliances to LV-PLC.
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  Energy-Saving Grounding Technology for Overhead Ground Wire of Power Transmission Line

  PENG Xiangyang, MAO Xianyin, HU Wei, WANG Yu, WANG Jianguo

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 84-90. https://doi.org/10.3969/j.issn.1000-7229.2014.08.015

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  Becaused of the electromagnetic induction between overhead ground wires and conductors, there is a huge power loss of overhead ground wires. Systematic study was carried out on the energy-saving grounding technology for overhead ground wires. The control principle of induced voltage of overhead ground wires was proposed, and different energy-saving grounding modes and calculation formula of segmented distance for overhead ground wires were presented according to single-circuit or double-circuit. Then, this paper proposed the selection requirements of ground wire insulator and its parallel gaps, and also introduced in detail how to choose the gap distance under standard atmospheric pressure, as well as different altitude, temperature and humidity conditions. For ground wire insulators in the icing area, this paper also proposed technical requirements of insulation configuration and DC ice melting. Finally, this paper suggested a variety of energy-saving splicing schemes of OPGW, and also introduced the common OPGW fittings. The proposed energy-saving grounding technology of overhead ground wires has been applied in Guangdong Power Grid, including overhead transmission lines in icing zone and non-icing zone.
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  Characteristics of Power Frequency Magnetic Field for AC Cable Circuits Laying in Tunnels

  LIU Ying, LI Wenpei, CAO Xiaolong, HAN Xiaopeng

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 91-96. https://doi.org/10.3969/j.issn.1000-7229.2014.08.016

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  In recent years, the electro-magnetic effect of underground power cables in cities on the environment and the public has caused widespread concern. The 2-D finite element analysis on magnetic field was used to set up simulation models for typical cable tunnels and to calculate the power frequency magnetic field inside and outside the tunnel, and the space distribution law and influence factors were discussed. It is found that the more the circuit number is, the denser cables are laid, or the higher the current is transmitted, the stronger the power frequency magnetic field inside and outside the tunnel will be. The distance from the cables is the key factor to determine the magnitude of the power frequency magnetic field. Magnetic cable brackets will cause the accumulation of magnetic field, so as to reduce the economy and safety of cable lines. In-site measurements of power frequency magnetic field were carried out in several cable tunnels, and the test data were in good agreement with the calculated values. The magnetic field strength levels at the pavement and ground surface of the cable tunnels discussed are lower than the exposure limits recommended by current standards.
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  Nonlinear Finite Element Static Analysis of Holding Pole with Double Flat Arms

  XU Chengcheng, YE Jianyun, ZHOU Huanlin

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 97-100. https://doi.org/10.3969/j.issn.1000-7229.2014.08.017

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  The strength and stability of the holding pole with double flat arms were analyzed. Based on the actual situation of holding pole, the typical numerical analysis load cases were selected with fully considering operation parameters of the holding pole. The static analysis of the holding pole subjected to the self-weight, lifting weight and wind load had been conducted by using the non-linear finite element method. The analysis results have played a guiding role on the construction scheme. The corresponding solving measures were proposed for load cases out of control conditions. Conclusions and suggestions can provide references for similar engineering design and construction.
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  Thermodynamic Ice-Melting Technology for AC/DC Transmission Lines

  XIANG Wang, TAN Yanjun, LU Jiazheng, HUA Yu, WEN Jinyu

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 101-107. https://doi.org/10.3969/j.issn.1000-7229.2014.08.018

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  According to the problem that the ice-coating of overhead transmission lines was harmful to the reliability of power transmission, this paper discussed various thermodynamic ice-melting technologies. The basic theory of the thermodynamic de-icing technology was introduced, especially the AC and DC de-icing method, as well as the status quo of AC de-icing schemes and DC de-icing device in China. Through the comparison of the characteristics of various AC de-icing methods and DC de-icing devices applied in AC/DC transmission lines, the application scopes of several de-icing methods were divided, and the future development of the DC de-icing devices was discussed.
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  Application of High Conductivity Aluminum-Clad Steel Reinforced Conductors in Transmission Line

  YE Hongsheng, MAO Qingchuan, WANG Bin

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 108-112. https://doi.org/10.3969/j.issn.1000-7229.2014.08.019

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  Aluminum-clad steel wire has the advantages of the good tensile strength of steel and the good conductivity of aluminum, and has much better anti-corrosion performance than zinc-coated steel wire, as well as the good thermal resistance. By replacing zinc-coated steel wire with 20.3% IACS aluminum-clad steel wire, and using high conductivity aluminum conductors, the composite energy-saving conductor has better mechanical performance, better sag characteristics, and better anti-corrosion performance than the zinc-coated steel reinforced cable, while keeps the same corona and electromagnetic environment characteristics. It is especially suitable for coastal or heavy polluted area. With using ACSR of 7%, 9%, 13% steel ratio, the resistivity of cable is reduced by 1.2%, 1.6%, 2.3%, respectively. Taking 500 kV transmission line as typical example, the saved energy loss can cover the extra conductor cost in 4 years, and give good financial benefit in following years. The aluminum-clad steel reinforced cable is worth popularizing.
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  Research and Application of Training Simulation System for UHVDC Converter Station

  GE Xianjun, PU Tianjiao, XU Zhengqing, LIU Kewen, CUI Shuang

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 113-118. https://doi.org/10.3969/j.issn.1000-7229.2014.08.020

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  Relying on ±800 kV Fufeng UHVDC project, the first set of training simulation system for UHVDC transmission system （UHVDC TS） was developed and implemented. This system can not only completely simulate the primary and secondary equipments, control-protection system in ±800 kV converter station, but also deeply simulate the monitoring system in converter station, as well as the UHV AC/DC hybrid power grid, which can achieve their integrated simulation. In addition, this system can achieve the overall scale and whole scene simulation for ±800 kV UHVDC, which can meet the training need of related personnel in UHVDC. This system has been successfully put into operation, and has obtained the good effect of training.
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  Physical Mechanism of Rotational Fourier Spectrum for Wind Turbine

  HE Guangling, TONG Hui

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 119-124. https://doi.org/10.3969/j.issn.1000-7229.2014.08.021

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  Conventional wind turbulent speed spectra are difficult to accurately predict the extreme loads and fatigue loads of wind turbines. To predict those loads accurately, based on a clear physical mechanism of blade rotational effect, a relationship between Fourier spectra and the cross-correlation function of samples was derived, and a rotational Fourier wind spectrum model was proposed. To comprehensively grasp the physical essence of rotational Fourier spectra, the main influencing parameters of rotational Fourier spectra were explored, including calculating radius, blade rotational speed, mean wind speed, surface roughness, etc. And then the analysis of corresponding parameter was carried out. The research results show that the rotational Fourier spectra have more physical meaning and engineering value compared with conventional wind turbulent speed spectra.
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  Tower Vibration Fault Diagnosis and Monitoring for Wind Turbines Based on RPCA

  ZHOU Jin, FANG Ning, GUO Peng

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 125-129. https://doi.org/10.3969/j.issn.1000-7229.2014.08.022

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  Vibration signal is one kind of important variables in supervisory control and data acquisition system （SCADA） for wind turbines. Based on SCADA data and wind turbine operating theory, this paper firstly analyzed the factors that had great influence on tower vibration. Then relative principal components analysis （RPCA） was used to model the tower vibration during the normal work of wind turbine combined with the SCADA data of a wind turbine between March and May 2011. Two statistic variables Hotelling T2 and SPE （squared prediction error） were calculated. The RPCA tower vibration model then was used to accurately detect the blade angle asymmetry fault, which could prove the effectiveness of this method.
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  Double-Fed Wind Generator Control Strategy in Three-Phase Symmetrical Fault

  XU Minghui, LI Zetao, TAO Jin

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 130-133. https://doi.org/10.3969/j.issn.1000-7229.2014.08.023

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  With the growing popularity of wind power generation system, double-fed wind generator （DFWG） as one of the most commonly used wind turbines, its problems are gradually revealed. Since wind energy has the characteristics of multiple uncontrollable factors and poor stability, it has brought many uncertainties for the grid control. To study the fault protection technology of double-fed wind power generation system in a three-phase symmetrical fault, firstly, this paper used the method of mathematical analysis to construct double-fed wind generator （DFWG） model, and analyzed the running state of the generator in three-phase symmetrical fault. Then Crowbar protection circuit was built； and voltage sag was simulated by a voltage sag generator in the experimental platform for testing. Finally, the verification was carried out through simulation. The experiment and simulation results show that the Crowbar circuit has significantly inhibition effect on current surge on the rotor side. So, the method of adding the Crowbar circuit to achieve low voltage ride through（LVRT ） in three-phase symmetrical fault is feasible.
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  Methane and Coal-Fired Combined Cycle Power Generation

  LI Jianfeng, LENG Jie, ZHAO Ming, CHAI Xiaojun, HUANG Haitao

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 134-139. https://doi.org/10.3969/j.issn.1000-7229.2014.08.024

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  Several existing modes of biomass power generation were summarized, and the method of combined cycle power generation of methane and coal was proposed. With this kind of power generation, the capacity choose of methane power generation can be flexibility according to the biomass resources around the plant, and the methane residue can be sold to local farmers as organic fertilizer. The combined cycle power generation has higher power generation efficiency compared with the pure biomass combustion power generation, and can obtain national high electrical price subsidies compared with co-firing power generation. So the combined cycle power generation has more obvious comprehensive advantages. Meanwhile, the methane produced in the fermentation of biomass can replace the oil consumption of ignition and combustion supporting, which can further improve the economic benefits of plant.
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  Evaluation Index Selection Method of Electric Power Inspection Benefits

  ZHANG Caiqing, LI Qi

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 140-144. https://doi.org/10.3969/j.issn.1000-7229.2014.08.025

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  The scientific evaluation of electric power inspection benefits can improve its effective development. The evaluation index system of electric power inspection benefits was initially established, including economic benefits and social benefits, based on its basic work programs and impacts on various aspects of power enterprises. The economic benefits were divided into direct economic benefits and indirect economic benefits； the social benefits included the contributions of the aspects which were the promotion of regional economic development, people's living standards, social stability, electricity order guarantee, environmental benefits and others. Based on the combination of traditional AHP and interval estimation method, a comprehensive index selection model was constructed including qualitative analysis and quantitative calculation. The evaluation index system of electric power inspection benefits was selected by using the model. The results show that the model has stronger operability and higher application value.
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  Evaluation Index System on Grid Physical Assets

  LI Peidong, HONG Menglin, SHANG Sang

  ELECTRIC POWER CONSTRUCTION. 2014, 35(8): 145-150. https://doi.org/10.3969/j.issn.1000-7229.2014.08.026

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  An important issue facing power grid enterprises is how to standardize grid physical assets management, maintain its healthy and integrity, optimize its allocation, dynamically monitor its distribution and operating conditions, predict the investment scales of its operation, maintenance and technological transformation. According to the core issue of assets evaluation in asset management strategy, this paper built the evaluation index system for grid physical assets from four dimensions: scale structural analysis, health level analysis, efficiency utilization analysis and retirement analysis, combined with life cycle asset management theory and asset wall model, based on the characteristics of grid physical assets management. The research results can provide references for deepening life cycle asset management, predicting the risks of operation, maintenance and technological transformation, and realizing economic and reliable operation of grid.