Table of Content

25 May 2015, Volume 48 Issue 5

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Security Column

Statistics and Analysis of Unplanned Outage of Thermal Power Generating Units in 2013

LI Jianfeng, ZHOU Hong, LU Junfu

2015, 48(5):  1-4.  DOI: 10.11930.2015.5.1

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The times and total duration of unplanned outages of thermal power units with the capacity of 100 MW grade and above in 2013 are counted and analyzed. The total times of unplanned outages of all the units are 920, and the total duration of unplanned outages is 53 443.5 hours. The times of unplanned outages caused by boilers and the boiler auxiliary equipment are more than 500, while the ones caused by turbine systems are more than 150. Through the analysis on the reasons for the unplanned outages caused by the boiler and turbine systems, the relative weak deficient parts that affect the unit reliabilities are figured out, which can provide the reference and basis for improving the routine maintenance and management of those deficient parts with poor reliabilities.

Inspection and Analysis of the Corrosion of 150-Meter Super High Reinforced Concrete Chimney and Flue

CUI Juanling, GUO Zhaosheng

2015, 48(5):  5-11.  DOI: 10.11930.2015.5.5

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Corrosion is more likely to happen in the chimney when thermal power plants are equipped with the wet limestone-gypsum FGD system but without the GGH system. Taking the 150-m super-high reinforced concrete chimney in a power plant for an example, the inspection and analysis of the chimney and flue surfaces, the concrete strength, the corrosion depth and the corrosion products are launched. The results show that the flue corrosion is more serious than the chimney corrosion, and most of the corrosion products are sulfates. In addition, it finds that the higher the chimney, the heavier the corrosion degree of the tube and the corrosion degree is distinctly different along the toroidal direction. The cause analysis concludes that preventing the neutralization reaction, improving the quality of chimney design and construction and strengthening the inspection and maintenance during operation are effective measures to prevent or alleviate the chimney corrosion.

Corrosion and Protection of Air-Cooled Condensers in Thermal Power Plant

DENG Yuqiang, LI Haiping, ZHANG Xiangjin, NI Ruitao, QI Dongdong, SONG Fei

2015, 48(5):  12-16.  DOI: 10.11930.2015.5.12

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The corrosion of air-cooled condensers (ACC) commonly exists in the operating units in China. Though the ferric concentration of feedwater can be made to meet the standards by installing deferrization facilities, the ACC corrosion is not solved thoroughly. In this paper, the causes of such corrosion are analyzed. The conclusion of the analysis is that it is the extra low partition coefficient of ammonia and high acidic anion in the initial condensate that makes the corrosion happen at low pH values. The test results show that the ACC corrosion can be controlled using the methods of either adding a few organic base to the exhaust steam or raising the ammonia concentration of the feedwater; while considering the corrosion control and operation safety, the former one is a better option, in order to control the corrosion and ensure the ACC operation safely, it is better to add a few organic base to the exhaust steam than others.

Pre-control Strategy and Case Study on Risks in Valve Test of Siemens 1 000-MW Steam Turbines

ZUO Shuai, ZHANG Zhiting, DAI Hongjun, CHEN Nianjun

2015, 48(5):  17-20.  DOI: 10.11930.2015.5.17

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Aiming at the possible risks in the process of valve test, this paper describes the actuation mechanism of valves and the valve test methods for Siemens 1 000-MW steam turbines. The risks in the valve test are analyzed. From analysis, it concludes that the abnormal reduction of EH oil pressure is the most serious risk and the steam turbine will trip when the EH oil pressure drops to a certain value. Considering the possible factors that cause the EH oil pressure to drop in the valve test, the pre-control strategy is established to optimize the control logics of the control valve and is applied on the four units of HPI Yuhuan Power Plant. A case study on the abnormal reduction of EH oil pressure in the course of the valve test of steam turbine shows that the pre-control strategy that has been applied in HPI Yuhuan Power Plant is reasonable and feasible.

A Variable Weights Transmission Equipment Condition Evaluation Method Based on Combined Weight Theory

WANG Qi, CHANG An, SONG Yunhai, SHEN Wen, LIU Yadong, SHENG Gehao

2015, 48(5):  21-26.  DOI: 10.11930.2015.5.21

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A fuzzy combined evaluation method for power transmission equipment condition is proposed. Based on combined weight theory, the proposed method adjusts weights based on the current status of different components in the transmission equipment. A systematic equipment status evaluation system is built through analysis of multiple system status information. By combining variable weight comprehensive theory, AHP method and entropy weight method, the complete weighting coefficients for all status information on the system are obtained. With full consideration of balance between evaluation factors and weighting coefficients change, the proposed fuzzy evaluation method can be used to assess overall transmission equipment operation status and predict system development trends. Finally, the validity of proposed method is verified by evaluation of a practical power transmission equipment condition.

Short-time Maintenance Schedule of HVDC Transmission Systems Based on Probabilistic Risk Assessment

WANG Tao, GUAN Lin

2015, 48(5):  27-30.  DOI: 10.11930.2015.5.27

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A novel risk evaluation method is proposed in this paper for planned maintenance of HVDC transmission systems by using probabilistic method, which can quantitatively evaluate the risk of HVDC transmission system maintenance on power grid reliability. Two major indices, including the loss of load probability(LOLP) and severity index(SI), are chosen to construct the power grid operation risk indices. Based on the calculation of historical operation data and advices of dispatching department, a risk threshold criterion is proposed for evaluating planned maintenance of HVDC transmission system, below which the planned maintenance can be approved. The methodology provides an effective analysis tool for scheduling department to choose the appropriate time to arrange maintenance. Finally, by taking the China Southern Power Grid as an example, a case study is carried out, which has demonstrated the high efficiency of the proposed method.

Development and Application of Transformer Fault Diagnosis Expert System

SHI Jiayan, ZHAO Xiaomin, SHI Yuansu, ZHANG Bing

2015, 48(5):  31-35.  DOI: 10.11930.2015.5.31

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This paper first introduces the establishment of a transformer fault diagnosis model, and then describes the overall design, main functions and business applications of a transformer fault diagnosis expert system. The advanced fault diagnosis techniques exploited in this paper follow practical use habits, and has no missing or wrong judgment during diagnosis process. It can provide rational and realistic maintenance decision based on property, severity and status of the fault. This system provides a good software platform for accurate fault diagnosis and maintenance of transformer equipment, and an effective method to reduce power generation and transmission cost.

Study on Solutions to Steam Flow Excited Vibration of a 1 000-MW Steam Turbine

LI Zhilong, LI Yanchao, YU Haidong, YE Shaoyi, LIU Shi

2015, 48(5):  36-40.  DOI: 10.11930.2015.5.36

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In this paper, the problem of steam flow excited vibration occurred in the debugging process of a 1 000-MW steam turbine is analyzed and the treatment procedure is summarized. Moreover, the vibration characteristics are also expounded. The online solutions to the steam flow excited vibration are thereafter put forward for large turbines with high parameters. The operation cases exhibit satisfactory results from online operational control measures.

Fault Diagnosis Method for Power Transformer Based on LS-SVM Probability Output of Bayesian Framework

QIN Peng, ZHAO Feng

2015, 48(5):  41-45.  DOI: 10.11930.2015.5.41

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In order to remedy the randomness and uncertainty in selection process, the parameters of the least squares support vector machines (LS-SVM) classifier are optimally selected by the Bayesian inference with three levels hierarchy which can significantly improves modeling efficiency. Combined with probability outputs of multiclass LS-SVMS, the Bayesian inference LS-SVM classification method is applied to diagnose the power transformer fault diagnosis. The experimental simulation results show that the proposed approach can identify faults successfully. Both the diagnosis accuracy and modeling efficiency are better than traditional LS-SVM method.

Location Analysis of GIS Circuit Resistance Defection

JIA Zhijie, ZHANG Bin

2015, 48(5):  46-50.  DOI: 10.11930.2015.5.46

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Circuit resistance measurement is one of the main items during hand-over test and routine test of GIS. The objective of the test is to check electrical equipment installation quality and loop circuit integrity. With consideration of common GIS inner conductor connection model, influencing factors of main loop resistance and shortcomings of circuit resistance measurement, a qualitative location analysis method is proposed to detect defective circuit resistance of 500 kV GIS. The method uses three steps to narrow search area, locate the defect and find out defective reason which includes diagnostic test, circuit breaker gas chamber check and disassembling inspection of TA gas chamber and grounding switch.

Analysis and Discussion on an Action of Optical Fiber Differential Protection

WANG Yuqiang, BAI Feng, MENG Lei, WANG Zhongquan

2015, 48(5):  51-55.  DOI: 10.11930.2015.5.51

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With the advantages of rapid action and strong anti-interference, the optical fiber current differential protection has been widely used as the main protection for the transmission lines in power systems and is used in the form of double protection for 220-kV transmission lines in a real power system. However, it is happened recently that the operation of the double protection is inconsistent with each other, which needs the technicians to draw their attention. In this paper, the in-depth analysis on this case is conducted from the aspects of protection principle, fault waveforms and TA selection to explore the features and causes of the protection action and find the preventive measures. The results indicate that this case is quite typical and can be regarded as the factor for type selection with TA. The corresponding preventive measurements can be provided for operators and maintainers to deal with the similar cases quickly and easily.

Power System Reliability Evaluation Based on Improved Sampling Method

ZHANG Weifeng, CHE Yanbo, LIN Jikeng, HU Shijun, LIU Hui, WEI Wenhui, LIN Changnian

2015, 48(5):  56-63.  DOI: 10.11930.2015.5.56

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In the case of random simulation of small probability events of component faults in power system, the traditional non sequential Monte Carlo simulation method for power system reliability evaluation has such defects as needing large sampling number and long simulation time. By combining antithetic variable sampling method with cross entropy importance sampling method, an improved sampling method, which is suitable for power system reliability evaluation, is therefore proposed. An approximate function with zero variance probability, whose optimal parameters of component are obtained using cross entropy importance sampling density function of component, is constructed first. Then the variances of reliability indices are further reduced through antithetic variable sampling according to the obtained optimal parameters. The sampling efficiency is thus improved and advantages of the two aforementioned methods are complemented. The proposed method, the traditional random sampling method, the antithetic variable sampling method and the cross entropy importance sampling method are respectively applied to reliability evaluation of IEEE-RTS and modified IEEE-RTS test system. A comparison of the results shows that, compared with the other three methods, the proposed method has higher sampling efficiency is improved, and its advantage is more obvious in rarer events.

Research on Protection Schemes for Distribution Network Considering Wind Power Supply Uncertainty

QIAN Lihong, WANG Wei, WEI Hua, HE Hao

2015, 48(5):  64-67.  DOI: 10.11930.2015.5.64

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The distribution network topology varies significantly with continuous improvement of wind power interconnection. The traditional protection scheme for the distribution network is severely affected with reduced protection reliability, sensitivity and failure of selectivity. Furthermore, the operational characteristics of wind power are susceptible to uncertain wind speed and directions, which add more complexity to protections. A sub-regional protection method with consideration of wind power supply uncertainty is proposed. The novel method is based on the analysis of wind power operational characteristics and reluctant to the wind power generation uncertainty. The simulation result verifies validity and effectiveness of proposed protection method.

Risk Group Evaluation Based on Cloud Model and Grey Incidence Decision-Making for Important Power Consumers

LI Cunbin, GAO Po

2015, 48(5):  68-74.  DOI: 10.11930.2015.5.68

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In order to reduce uncertainty caused by expert subjective perception and experience level during construction of important power consumer risk evaluation system, a risk group evaluation method based on cloud model and grey incidence decision-making analysis is proposed. The method converts fuzzy subjective evaluation to interval values using cloud rules in normal Cloud model, and then the risk was evaluated by gray incidence decision-making analysis method. Result comparison with other evaluation method in a specific case shows the validity of proposed method. The research showed that the method could evaluate the important power consumer risk more effectively and objectively.

Secure Access of Electric Power Mobile Terminal Using SM2-Crypto-system-Based SD Card

WANG Zhihe, LUO Zhao, XIE Jihua,, GU Wei, CHEN Haichao, XU Chao, ZHOU Liang

2015, 48(5):  75-80.  DOI: 10.11930.2015.5.75

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With the wide application of mobile terminals into smart grid, it is urgent on the agenda to ensure the more secure access of mobile terminal to power information network. In view of the situation that the mostly used public key algorithms of encrypted SD card is RSA, a new secure access solution of electric power mobile terminal is proposed by using SM2-crypto-system-based SD card. An analysis is made on the SM2-crypto-system-based SD card, the network and application framework of the proposed solution. Meanwhile, the proxy function and the SD card secure application function are tested by using the Android mobile phone as the electrical power mobile terminal, which validates the feasibility and safety of the proposed solution. The SD card has been piloted in a provincial power grid, and the result proves that the proposed solution can be used as a reference for improving the active defense ability of mobile terminals and promoting the localization of electrical power information security products.

Study on Mechanism and Strategy of Cybersecurity in U.S. Electric Power Industry

ZHU Xiaoyan, FANG Quan

2015, 48(5):  81-88.  DOI: 10.11930.2015.5.81

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Cyber threats to electric power system have great impact on the national security, public safety and country economy. After years of researches and practices, the United States of America (US) has well formed a multi-party cooperative mechanism for the cybersecurity to safeguard the operation of electric power industry. The cybersecurity framework and strategy for electric power industry in US is presented first. The corresponding duty and its working status of related government agencies and organizations involved in the cybersecurity of the electric power industry is then introduced respectively. The study results and working conclusions of US research institutions and organizations are also briefed. Based on those information, the characteristics of cyber security mechanism in US are studied and analyzed from different points of view including cyber security standard, culture construction, risk management, collaboration and information sharing, and effective response to cyber-attacks. In order to sustain the cybersecurity and evolvement of power information security, not only the standard and specification are required to be continuously improved and actively implemented, but also the culture of security, the risk management, the collaboration and information sharing, the effective response to cyber-attacks are needed to be effectively coordinated and managed.

Energy Conservation and Environmental Protection

Research on the Technical Route and Industrial Application of Near-Zero Emission of Coal-Fired Power Plants Supplied with Shenhua Coal

ZHOU Hongguang, ZHAO Lei, CHEN Chuangshe, LI Min

2015, 48(5):  89-92.  DOI: 10.11930.2015.5.89

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Presently, the coal consumption of coal-fired power generation industry accounts for 50% of the total energy consumption in the country, which makes it the major root of air pollutants. In order to achieve the goal of near-zero emission for coal-fired power plants and alleviate environmental pollution, in this paper, the necessity of emission reduction and the concept of near-zero emission are introduced. In particular, regarding the characteristics of Shenhua coal, such as low ash, low sulfur, low nitrogen and low mercury contents, the study on coordinated dust removal, efficient desulphurization and low-NOx combustion integrated with SCR denitration is conducted, which formulates the technical route for near-zero emission of coal-fired power plants supplied with Shenhua coal. All the applications demonstrate that this technical route is of great significance for near-zero air pollutant emissions from coal-fired power plants.

Research and Practice on Dust Emission Reduction Technology in 350 MW Coal-Fired Generator Unit

SHI Xiaohong，, LI Guangbin, WEI Shuzhou, ZHAO Rui

2015, 48(5):  93-96.  DOI: 10.11930.2015.5.93

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In order to reduce the dust emission concentration as it is required in“Emission Standard of Air Pollutants for Thermal Power Plants (GB 13223-2011)”, the technical studies on dust emission reduction are carried out on a 350-MW unit of Sanhe Power Plant, which include a series of measures taken collaboratively, such as the installation of low-temperature economizer before the electrostatic precipitator, the comprehensive upgrading of the electrostatic precipitator, the retrofit of the demister in the desulfurization system and the installation of wet electrostatic precipitator behind the FGD system. After the improvements above, the monitoring result shows that the dust emission concentration of flue gas is limited between 2.74-3.62 mg/m3, lower than 5 mg/m3, which can fully satisfy the requirement of national emission standard.

Generation Technology

Combustion Optimization for a 1 000-MW Ultra Supercritical Boiler

GUO Jie, QIN Xichao

2015, 48(5):  97-102.  DOI: 10.11930.2015.5.97

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Aiming at the problem of uneven combustion in a 1 000-MW ultra supercritical boiler, the in-depth combustion optimization tests are conducted, including combustion air distribution optimization, primary air volume optimization, coal powder fineness adjustment and total combustion air distribution adjustment. Through the tests, the optimal operation curve is obtained. The combustion test under different load conditions exhibits that after the combustion optimization, the fan power consumption, the NOx emissions as well as the heat losses of exhaust flue gas and unburned carbon are all reduced. Hence the boiler efficiency is improved and the effectiveness of the combustion optimization is verified.

Operation Optimization of Circulating Pump in 1 000-MW Direct Seawater Cooling Generating Unit under Tidal Variations

LI Dacai

2015, 48(5):  103-108.  DOI: 10.11930.2015.5.103

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In order to further explore the economic operation modes of circulating water pump in direct seawater cooling units of large coastal thermal power plants , the mathematical model of the circulating water system under the influences of tides is established based on experimental studies and online optimization calculation method. Also by virtual of the data pool method, the circulation water pump operation mode is optimized step by step. The optimization objective is set to be the minimization of online coal consumption. In this way the model for the pump operation optimization is established, such that the optimal operation modes under different tide, seawater temperature and load conditions are obtained. Meanwhile, based on unit coal saving forecasts under different pump operation modes considering the loading conditions of the generation units, the optimal pump operation modes in future time intervals are obtained to provide guidance for the practical operation. The application of the online optimization method in Chaozhou Power Generation Company shows that the circulating water system has achieved very good energy-saving effects.

Research and Application of Speed-Control System Modeling of F-Class Gas Turbines

SHAN Yinglei，, LI Fuxing, LI Wenfeng, WANG Guanhong

2015, 48(5):  109-114.  DOI: 10.11930.2015.5.109

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Based on the tests on the load-frequency control strategies and static frequency characteristics of the speed-control system of a F-class heavy-duty gas turbine, the analysis of the adaptability of the governor and prime mover models provided by the PSD-BPA software, and from the security aspect of power grid frequency as well, a new model is established for the speed-control system of the domestic mainstream F-class gas turbines and the corresponding testing method is also proposed The comparison between the simulation results and the testing data shows that the new model can well describe the practical frequency control process. With the increasing of gas turbines, the real load-frequency characteristics can be better simulated with the new model, which is crucial to the perfection of the simulation database, the analysis of the power system transient stability, the study on the power grid control strategy and the formulation of security warning measures.

Economic Analysis on Waste Heat Recovery Technique Applied for Make-up Water Heating in the Absorption Heat Pumps of Thermal Power Units

HUO Peng, LI Qianjun, ZHENG Likun

2015, 48(5):  115-119.  DOI: 10.11930.2015.5.115

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Characterized by extracting high quality heat from low quality heat, the absorption-type heat pump can be used in retrofit project for energy-saving purposes. However, if the pump is applied in thermal power plants, the differences in thermal systems, driving heat sources and implementation locations of recovered waste heat will yield completely different results. In this paper, through the economic analysis on the waste heat recovery technique which is used to heat up the make-up water in two types of units, it is clarified that waste heat recovery may not achieve the goal of energy saving because of the cold end losses and the quality of the waste heat. When the waste heat recovered from the circulating water by heat pump is completely used to heat up the water of heat-supply network, the thermal efficiency of units can be improved, but when it is only used for the unit itself, it may not fulfill the objective of becoming more energy efficient.

Experimental Research on Temperature Transfer Characteristics of Coal Pile in Closed Coal Yard

WANG Huan, ZHOU Yonggang, LI Pei, WANG Binghui, ZHAO Hong

2015, 48(5):  120-124.  DOI: 10.11930.2015.5.120

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The closed coal yard has become the new style of coal storage in coal-fired power plants thanks to its advantages of less pollution to the environment and capabilities of maintaining coal yard safe operation during bad weathers, etc. In this paper, the coal heap of the closed coal yard is simulated to study the heat transfer characteristics. The experiment results show that on the upper side of the heat source point, the heat transfer is the strongest, and in the left and right side areas it is next to the upper side, while it is the weakest in the lower side area. Moreover, with the total moisture in the coal sample reduced, the impact of moisture on temperature transfer characteristics weakens. When the temperature of the heat source point is lowered, the unevenness of the temperature transfer around the heat source point is alleviated. Therefore, more thermometers should be installed below the high-temperature area, and the alarm temperature in the lower side area of the heat source should be set lower than that in the upper side area.

Power System

Study on VFTO Charaterstics of GIS in 750 kV Substation

WANG Lei

2015, 48(5):  125-132.  DOI: 10.11930.2015.5.125

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The current studies of very fast transient overvoltage(VFTO) in GIS are mostly concentrated in microcosmic aspects and some achievements have been gained. Consequently, it is significant to investigate VFTO characteristics of GIS from macro respect by using existing research results in microcosmic respects. In this paper, by taking the Shahu 750 kV substation in Ningxia as an example, a dynamic arcing model is built with the software ATP-EMTP, and a detailed analysis is made of the effect of operation modes and order on VFTO and the inhibitory effect of shunt resistance on VFTO is checked. The simulation results show that the amplitude of VFTO is not only related to the operation mode but also associated with the operation order. Therefore, the VFTO does not pose a serious threat to the insulation of internal GIS and transformer windings in view of amplitude. The study results can provide a useful reference and basis for 750 kV GIS equipment development and substation operation.

Research and Discussion on a Method for Topology Identification of Distribution System

LI Hong, ZHANG Zhanlong, GAO Yajing

2015, 48(5):  133-138.  DOI: 10.11930.2015.5.133

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The real-time measurements in distribution network are very limited, and it is a technical challenge to identify the topology of distribution network. In this paper, the concept of optimal matching loop power is proposed. Based on optimal matching loop power, an efficient iden-tification method is developed, which can find out several possible topologies. Then, the state es-timator is used to choose the most reasonable topology with the minimal measurement residuals. In the proposed method, the topology identification is converted to the problem of network recon-figuration whose objective is the minimal measurement residuals. Numerical tests prove that the proposed method is potentially applicable to the practice.

Corrosion Failure Analysis and Protection for Tower Foot of Hot Galvanized Transmission Tower

CHEN Tong, ZHUANG Jianhuang, HUANG Weilin, TAN Tian, ZHANG Junxi

2015, 48(5):  139-143.  DOI: 10.11930.2015.5.139

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The fastness of transmission tower is very important to transmission line operation safety. The simulation test for tower foot corrosion under special environment is performed; and the corrosion mechanism is investigated by using electrochemical measurement. Results show that the corrosion is caused by the dust cover which exposed to environment rich in water and oxygen. The protection measure is proposed based on the corrosion mechanism and applied in transmission line tower. The re-test shows the proposed protection measure has anticipated effect.

A New Approach to Damp SSR by Adjusting Equivalent Output Impedance of VSC

CHEN Jianguo, XU Meimei, XU Yutao, QIAO Yuchao, XU Zhenyu, GAO Ziqiang, ZHANG Xu, ZHENG Wei, LIANG Xinyan

2015, 48(5):  144-149.  DOI: 10.11930.2015.5.144

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Serious subsynchronous resonance(SSR) will threaten the operation of power system. An investigation and analysis is made in this paper of the effect of a voltage-source converter (VSC) on sub-synchronous resonance which is installed near the synchronous generator. The equivalent output impedance of VSC, which is made up of a series of circuit components, and its control parameters are the key factors for interactions with the grid. The effect of the equivalent output impedance of VSC on the damping of the system with the complex torque coefficient method is analyzed, and then, the VSC is further improved to increase the equivalent implanted damping resistance and to achieve the damping subsynchronous resonance. The time-domain simulation proves that the VSC impedance adjustment technology can damp the subsynchronous resonance to a certain extent.

Smart Grid

Study on Charging and Swapping System for Electric Vehicle in Hybrid AC/DC Micro-grid

ZHENG Rui，, HAN Xiaoqing, ZHANG Junliu, WANG Peng, ZHANG Peng

2015, 48(5):  150-155.  DOI: 10.11930.2015.5.150

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Against the background of the electric vehicles(EVs) development, energy saving and emission reduction, improving the charging efficiency of EVs has become researching focus. An EV charging and swapping energy management system and a bi-directional DC/DC converter control strategy, which can organically combine the EV charging and swapping electric devices with the energy storage devices of the hybrid AC/DC micro-grid, is designed in the paper. The simulation results show that the proposed system is not only effective on load shifting, energy saving, emission reduction and cost saving, but also useful to promote the development of EV technology.

Study on the Whole System Synchronization Testing Method in Smart Substation

ZHAO Yongsheng, LIU Haifeng, LIANG Wenwu, LI Hui

2015, 48(5):  156-160.  DOI: 10.11930.2015.5.156

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The whole system testing is a key item for checking the sampling synchronization of relay protection equipment and the wiring correctness of loop. The problems of whole system synchronization testing caused by distributed sampling in smart substation is firstly analyzed in this paper. And then the advantages, disadvantages and adaptability of the two conventional testing methods are compared and discussed. A new testing method and its function design are proposed based on the total station GPS synchronous signal extension device. The testing results show that this method has high precision and good adaptability.