Table of Content

25 February 2015, Volume 48 Issue 2

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Generation Technology

Modeling, Simulation and Verification of Turbine Governing System Based on PSASP and Simulink

SHENG Kai, WEI Le, JIANG Xiaolong, XUN Xin

2015, 48(2):  1-6.  DOI: 10.11930.2015.2.1

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As the model of the steam turbine governing system is the basic data to analyze the stability of the power system, its accuracy determines the reliability of the power system analysis. Therefore, simulation and verification are necessary for the established model to ensure the model quality. In this paper, aiming at the difficulties in modeling, simulation and verification through the professional power system calculation program(such as PSASP) due to the complex coordinated control system in the steam turbine governing system of thermal power generating units, a joint modeling method is proposed based on flexible Simulink and professional PSASP to realize the modeling, simulation and verification of the governing system. The results of the simulation and verification indicate that an accurate model can be established with this method and meet the verification requirements.

Heat Transfer Characteristics Analysis and Design Optimization for Oxy-Fuel Boilers

LIAO Haiyan

2015, 48(2):  7-13.  DOI: 10.11930.2015.2.7

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In order to obtain the design principle of oxy-fuel boiler. The heat transfer of 200 MW boilers adopting oxy-fuel combustion is calculated and analyzed in this paper. The result shows that compared with air-firing, the radiant heat transfer of oxy-fuel combustion will be enhanced in high flue gas temperature zone due to the higher concentration of CO2 and H2O. While in the low flue gas temperature zone, the convective heat transfer will weaken due to the decrease of flue gas volume flow rate. Based on the analysis of heat transfer characteristics, the design optimization method on flue gas flow section and heat transfer areas for oxy-fuel combustion boiler is proposed. Under the condition of the oxygen concentration at 26%, the flow section area in oxy-fuel combustion boiler can be reduced by 15%~21% in dry cycles and 13%~24% in wet cycles. And at the same time, the heat transfer area can be decreased by 9%~32% in dry cycles and 7%~35% in wet cycles. In oxy-fuel combustion boilers, the flue gas flow velocity can soon meet the design requirements with the heat transfer consistent with air-firing boilers. This work is supported by Shenhua Group Technology Innoration Project No.[2011]368.

Steam Distribution Strategy Optimization for 600-MW Steam Turbine under Partial Admission Conditions

TANG Guiji, ZHANG Wende, LU Shengyang, MU Fahai, GAO Xiang

2015, 48(2):  14-20.  DOI: 10.11930.2015.2.14

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Aiming at the faults of large vibration amplitude and high bearing shell temperature in the inadequate valve management programs of 600-MW steam turbines, the frequency spectrum of the excitation force of one regulating stage blade is calculated with Matlab and compared with the natural frequency of the high-pressure rotor in different valve management programs. Then the bearing dynamic characteristics are calculated with Matlab programs in different valve management programs and input into Ansys. Finally, the stability indices of different valve management programs are obtained and the optimal valve management program is determined. Based on the above results, two improved regulating stage admission structures corresponding to fixed and unfixed peak regulation ranges are put forward, which provides a new thought for the design and manufacture of new units and for the flow path retrofit of the old ones.

Effects of Ash Deposition and Face Velocity on the Performance of a Direct Air-Cooling Power Unit

WANG Li, ZHANG Yijiang, GUO Minchen, JI Zhiqin

2015, 48(2):  21-26.  DOI: 10.11930.2015.2.21

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Ash deposition and face velocity reduction are the major factors which cause the backpressure increase of direct air-cooling power units. In this paper, the effects of ash deposition and face velocity on the backpressure and heat transfer coefficient are analyzed taking a 330-MW direct air-cooling power unit as a case and the preventive measures are proposed. The results show that as the ash thickness reaches 1.0 mm, the backpressure increases from the designated 34.0 kPa to 49.0 kPa , and the power output decreases 8.6 MW; when the face velocity drops from 2.2 m/s to 1.6 m/s, the backpressure increases from the designated 34.0 kPa to 50.1 kPa and the power output decreases 9.4 MW.

Modification of Seal Ring Housing for M701F3 Gas Turbines

WANG Qingren

2015, 48(2):  27-30.  DOI: 10.11930.2015.2.27

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The high disc temperature(DCT) of M701F3 gas turbine which is caused by the wear and tear on the downstream side of seal ring housing threatens the security and economical efficiency of the unit operation. In this paper, the necessity and scheme for the technical retrofit are expounded with detailed key processing and constructing techniques. The technical difficulties encountered such as the accuracy of machine tools, and the innovation of computer numerical control, lathe and cutting tools, as well as drill stems and heads, are solved with the manufacturing technique and standards improved. In addition, the modifications of the seal ring housings from the second to fourth stages turn out to be a big breakthrough in local manufacturing techniques, which will have very promising prospects to popularize.

Analysis on Temperature Control for PG9171E Gas Turbines

FU Zhaolong, LIU Zhiyong, ZHANG Kunpeng, XIE Meifang

2015, 48(2):  31-37.  DOI: 10.11930.2015.2.31

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The inlet gas temperature of the gas turbine affects the turbine’s output power and its thermal efficiency, while the temperature control of the turbine is eventually realized through the inlet gas temperature control. In this paper, in consideration of the relationship between the inlet and exhaust gas temperatures, the exhaust gas temperature is measured to indirectly obtain the inlet gas temperature. The control logic is introduced to analyze the protections and control curves of the exhaust temperature. In addition, the impact of the external ambient conditions on the temperature control is studied, from which the adjustment instruction on the temperature control is presented based on practical operation data. The analysis indicates that in the gas turbines of PG9171E type, the accuracy of major measurement data and the changes of the ambient conditions have great effect on its temperature control.

A Method of Circulating Water Concentration Rate Stabilization and its Application

XU Zhen, JIANG Xiaoyan, SU Yan, MAO Jin, JIANG Qi, LI Yajuan

2015, 48(2):  38-40.  DOI: 10.11930.2015.2.38

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In order to solve the problem of wide fluctuations of circulating water concentration rate in some power plants, Huaneng Dezhou Power Plant is taken as an example to analyze the relationship between the concentration rate and the conductivity of the cooling water Based on the analysis and with the combination of the DCS control system, the control system for circulating water concentration rate stabilization is established. The application results indicate that the system conducts real-time monitoring accurately, is easy to operate, effectively buffers the considerable fluctuation of circulating water concentration rate caused by heavy blowdown and ensures the steady operation of circulating water with high concentration rate.

Study on Process of Slag Water Circulation System in Coal-Fired Power Plants

SU Yan, LEI Fangyu, JIANG Qi, XU Zhen, JiANG Xiaoyan

2015, 48(2):  41-44.  DOI: 10.11930.2015.2.41

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In this paper, the current operation state of the wet slag disposal system of four 300-MW units in a coal-fired power plant of Zhejiang is analyzed, and the study on flushing slag water reduction of the slag disposal system is carried out. The practical results indicate that the formation of calcium carbonate scale can be constrained effectively by adding an appropriate amount of scale inhibitors to the slag water circulating system, and the circulating flushing slag water can be cooled down by using a water cooler. By building the enclosed slag water circulating system, both the make-up and discharged wastewater are greatly reduced, which exhibits significant economic and environmental benefits.

Power System

A Short-Term Power Load Forecasting Method Based on Fuzzy Rough Sets and Support Vector Machine

ZHAO Huicai, CHEN Yuehui, CHEN Ruixian, PENG Ziyang

2015, 48(2):  45-48.  DOI: 10.11930.2015.2.45

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Aiming at the defects of long training time and slow speed due to redundant information and mass data in the support vector machine (SVM) based load forecasting and taking advantage of imprecise or incomplete knowledge and redundancy information handling by fuzzy rough sets (FRS), a short-term load forecasting model combining SVM and FRS is proposed, in which the attribute reduction algorithm of FRS is used to deal with the information bloat of the numerous power load affecting factors and eliminate the factors irrelevant to decision-making information; then, the simplified factors are input into SVM to conduct the forecasting. The simulation result shows that this forecasting model can ensure the prediction accuracy and speed up the calculation.

Development and Application of Multi-channel Lightning Current On-line Monitoring System

DUANMU Linnan, YU Zhanqing, PENG Long, CHENG Yi, ZHAO Yuan, LI Yu

2015, 48(2):  49-51.  DOI: 10.11930.2015.2.49

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Measurement of lightning current characteristic parameters are very important for study of lightning process and protection. An on-line monitoring system for multi-channel lightning current is developed in this paper. A flexible Rogowski coil lightning current sensor is designed to convert high lightning flow to low voltage signal by electromagnetic coupling. A high-speed data acquisition and processing unit is used to acquire voltage signal to ensure the integrity and accuracy of the signal. The wireless data transmission is based on GPRS. The expert analysis system, which is remotely controlled on the purpose of stable operation, is used for analysis and processing of the received lightning current waveform signal. The system has been implemented in the 500 kV Shenbao Ⅰ-Ⅱ and Taishan Ⅰ-Ⅱ transmission lines, in which a lightning current waveform was successfully caught on June 25, 2013 and its characteristic parameters were monitored and the lightning current waveform data were recorded, which can provide the basic data for lightning current comparison and simulation inversion.

Research on Lightning Invasion Wave Overvoltage in Flexible DC Converter Station

LI Tianwei, LIU Dapeng, LEI Yuanyuan, ZHAO Yuming

2015, 48(2):  55-58.  DOI: 10.11930.2015.2.55

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To confirm the lightning insulation level of the equipment in DC yard and the cable in converter station, a electromagnetic transient simulation model is built for flexible DC transmission project, which consists of a 1~2 km long DC transmission line in the entrance segment and a converter station. The lightning stroke current is calculated based on the electrical and structural parameters of tower-insulator-conductor. The lightning current wave is simulated by applying dual-exponential function. The tower gap flashover criterion is determined according to intersection method. The lightning invasion wave overvoltage caused by main equipment and cable in DC yard is calculated with the overhead transmission line suffering lightning. The insulation level is determined through simulation for the main equipment and cable in DC yard. In addition, the simulation shows that the DC reactor plays a certain role in controlling lightning invasion overvoltage.

Analysis on Characteristic Data Stability and Fault Mechanism of Circuit Breaker Mechanical Characteristics

LI Bin, HAO Jiancheng, LIU Yitao, YU Zaiming

2015, 48(2):  59-65.  DOI: 10.11930.2015.2.59

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In order to study the reliability of the characteristic data and the change features of the fault characteristic data in diagnosis and assessment of high voltage circuit breakers, a data acquisition platform is constructed for such three signals as the circuit breaker contact trip signal, the operating mechanism current signal and the mechanical vibration signal, and an acquisition method is also proposed to obtain the eigenvalue of above 3 signals. Under the condition of different time and same state of circuit breaker, the stability of the characteristics data of each signal has been investigated. A study is made on the change features of the characteristic data of above three signals under three different operating states as resistance increases of operating mechanism control loop, single taking off of the opening spring and jam fault of the operating and transmission mechanism. The reliability of the data acquisition system and the feasibility of the data feature extraction method have been tested in this study, and the change features of the characteristic data of each single are obtained under different states of circuit breaker mechanical characteristics, which can provide an data support for diagnosis and assessment of high voltage circuit breakers.

Improved Method for Shielding Failure Trip-Out Rate Calculation for EHV/UHV Power Transmission Lines

PAN Wenxia, HUANG Tao, ZHOU Wei, HE Huiwen

2015, 48(2):  66-69.  DOI: 10.11930.2015.2.66

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In this paper, based on the structural characteristics of extra and ultra high voltage towers, the traditional electrical geometric model (EGM) is upgraded with the concept of striking distance correction factor being presented, which can make the model accord with the extra and ultra high voltage towers better. The improved electrical distance calculation method for solving the maximum striking distance of EGM is proposed from the perspective of geometry and is applied to the calculation of shielding failure trip-out rate for extra and ultra high voltage lines. The calculation results indicate that the improved calculation method is more accurate and reliable than the traditional one.

Study on Connection Performance of D-Shaped Composite Tube

XING Haijun, YUE Ping, WANG Cancan, JIANG Wendong, WANG Jiajia, ZHANG Yingjie

2015, 48(2):  70-75.  DOI: 10.11930.2015.2.70

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The D-shaped composite tube which is mechanically connected by steel bolts is applied to the lattice composite tower. However, there is still lack of enough studies on the impacts of machining hole and bolt pre-tightening force on the rod bearing capacity and the bearing properties are still unclear in the current field. In order to understand the connection performance of D-shaped composite tube, the node test on the inter-node model of the tower with D-shaped composite tube is carried out, which concludes that the damage type on top of the connection hole of the composite rod is mainly slipping off and shearing. Then, the analysis on the impact of bolt pre-tightening force on the connection performance of D-shaped composite tube is conducted with the finite element model. The analysis result indicates that the value of pre-tightening torque of the shear bolts for D-shaped composite tower should be 220 Nom.

Study on Manufacturing Process and Quality Control of Extra High Strength Steel Reinforced Aluminum-Alloy Conductors in the Yellow River Long-Span Section of Hazheng Transmission Project

JIN Rong, LI Yan, YOU Weiren, FENG Aijun, LIU Lei, MIAO Xiaolin, GU Sunwang

2015, 48(2):  76-80.  DOI: 10.11930.2015.2.76

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The 900-mm2 large-section high strength steel reinforced aluminum-alloy cable is firstly applied in the Yellow River large-span section of Hazheng 800-kV UHVDC transmission project. In this paper, the key points of the conductor manufacturing process are analyzed with the difficulties of quality control being summarized. Then, the analysis on the quality of the traditional manufacturing method is conducted and the improving measurements are put forward according to the related technical requirements, which solves the problem of quality control of 900-mm2 large-section high strength steel reinforced aluminum-alloy cable manufacturing. Through the improvement of manufacturing process, the conductivity is stabilized at 53%IACS and the strength of single wire is increased to 310 MPa. Meanwhile, the hydrogen and impurity contents are largely reduced by more than 60% and 70%, respectively. Therefore, both the energy economy and the supply security of transmission lines are obtained.

Research of power network model integration under integrated maintenance mode of EMS

CAO Wei, WANG Yanchu, GU Quan, YU Xiaomin

2015, 48(2):  81-84.  DOI: 10.11930.2015.2.81

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Currently, classified maintenance and model splicing are widely used in power dispatching system, that is, the subordinate grids establish their own models and graphics within their coverage and adopt equivalent treatment for the outside system; while the superior grid establish the network model by splicing the models and graphs of the subordinate grids. However, in real cases, model distortion and inconsistent graphic-model usually make the superior grid difficult to obtain a complete and accurate grid model, and the spliced model is often inconsistent with the graphics. In this paper, a new method of power network model integration is described. By the modification to the maintenance tools of the dispatching system, a panoramic model is maintained by power staffs at all levels, and different information sections and graphical display can be obtained through the view. In the responsibility area of access control, maintenance staffs at all levels are limited to the models and graphics within their coverage and can no longer adopt equivalent treatment for the outside system. The model integrity and consistency can be then solved in the maintenance phase. Finally, the application of the method in the new OCS system of Guangxi in China Southern Power Grid is introduced, which verifies the practicality of the method.

Design and Application of State Estimation Intelligent Analysis

NING Jian, WANG Yi, ZOU Dehu, LUO Yuchun

2015, 48(2):  85-89.  DOI: 10.11930.2015.2.85

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In this paper, a summary is made of the problems existing in measurement and model validation of the state estimation (SE) module of the North China Power Grid Smart Grid Operation Support System(SG-OSS), and the limitations of the existing SE are pointed out in operation of the real system. According to the defect that the existing SE can only provide the calculation functions but cannot make intelligent analysis of the real data, it is proposed to build the intelligent analysis function of SE to enhance the real project application effects of the SE. The intelligence analysis functions include such modules as measurement error check, intelligent analysis, problem location, result display and query, which can make the measurements error be located. The operation in the North China power grid SG-OSS shows that the intelligence analysis capabilities can accurately locate the data errors of power grid, which can improve the quality of basic data and the efficiency of automatic maintenance. The operation results indicate that the system can be widely applied.

Study on the Application of SVC in Load Centers of Guangdong Power Grid

YANG Fenyan, HUANG Hongyang, XU Zheng

2015, 48(2):  90-93.  DOI: 10.11930.2015.2.90

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With the rapid growth of loads and external electric power infeed, the voltage stability in the load centers of the Pearl River Delta of Guangdong power grid is becoming increasingly prominent. In this paper, the voltage stability in the load centers of Guangdong power grid is investigated from the aspects of both the static and transient voltage stabilities and it is concluded that the 220-kV substations are prone to voltage instability. Therefore, the preliminary SVC application scheme is proposed in combination with the practical construction conditions of these substations and the availability of the scheme is verified from the aspects of both the static and transient stabilities. The result shows that the proposed scheme can enhance the voltage support in the load centers of Guangdong power grid and benefit the transient voltage stability of the system significantly.

Application of Infrared Diagnosing Technology in Distribution Network

LI Xinxing, LU Hongbao, HE Liang, LIN Xuan

2015, 48(2):  94-97.  DOI: 10.11930.2015.2.94

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Based on a case study, the detection method and defect diagnosis of distribution network equipment are analyzed and discussed in the paper. The infrared diagnosing technology can be used to monitor the operation state of equipment and timely discover and remove the fault. In this way, the emergency accident can be greatly reduced and the power supply reliability can be improved.

Information and Communication

3D Visualization Technique of Transmission Line Corridors: System Design and Implementation

MAI Xiaoming, CHEN Chi，, PENG Xiangyang, ZHANG Boyu，, WANG Ke, YANG Bisheng，, WANG Rui

2015, 48(2):  98-103.  DOI: 10.11930.2015.2.98

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To fulfill the demand of transmission line inspection and maintenance, a transmission line corridor 3D visualization system is developed by 3D modeling of the corridors with the mass laser scanning data obtained by an unmanned helicopter equipped with multiple remote sensing sensors. With this system, the Laser point cloud and its derived topology is adopted as the basic geometry reference of the transmission line corridors to achieve a high accuracy reconstruction of the real corridors status, including the geometric modeling of surrounding topography, man-made objects, power line, tower and their multispectral representing. Besides, a 3D real-time visualization can be realized for the flight process of unmanned helicopter module. Experiment using UAV borne inspection data including LiDAR data and imagery has proved the feasibility and effectiveness of this system.

Application of Various Relay Modes for Transmission Line Inspection with Large-Size Unmanned Helicopters

WU Feilong, LIN Han, TANG Mingwen, ZHENG Xiaoli

2015, 48(2):  104-110.  DOI: 10.11930.2015.2.104

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Relay technology in communication data link is the bottleneck for large-size unmanned helicopters to perform long-distance, over-the-horizon transmission line inspection flight. In this paper, various relay modes and feasibility are analyzed and evaluated, and the application and field validation of various relay modes for large-size unmanned helicopter transmission line inspection is presented, including aerial relays using unmanned helicopters, ground fixed relays, vehicle mobile relays and OPGW optical fiber relays. The method and experience of setting up ground relay stations by using available resources according to real circumstances are introduced. In addition, some suggestions are provided about relay modes for unmanned helicopter inspection. It is also proposed to build up a database of relay resources for communication data link, so as to provide real-time communication technical support for practical unmanned helicopter inspection.

Cloud-Computing Based Power Big Data Analysis Technology and Its Application

WU Kaifeng, LIU Wantao, LI Yanhu, SU Yipeng, XIAO Zheng, PEI Xubin, HU Songlin

2015, 48(2):  111-116.  DOI: 10.11930.2015.2.111

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In order to deal with the bottlenecks of the performance and scalability of power data analysis in present big data era and meet the requirements of power production and marking systems, the advantages of cloud computing technology is firstly analyzed, then the architecture and key techniques of Hadoop-based power big data analysis system are proposed. The architecture combines the characteristics of power big data and the emerging cloud computing technology, and includes three key technologies, i.e., the distributed gridfile based multi-dimensional index, the automatic SQL to HiveQL translation tool and the hybrid data storage model, which can support data update operation. Therefore, the traditional power data analysis system can be improved and updated. The application of the system in the power information collection system in Zhejiang indicates that the performance of the system is improved by 5 times with only one-eighth of the hardware configuration as compared with the traditional system. This proves that the cloud computing technology can significantly improve the performance and reduce the cost of big data acquisition and analysis.

Power Planning

Research and Development of Transmission Network Expansion Planning Platform with

XIAO Bai, YANG Lin, MU Gang, ZHAO Lijun, DONG Xiaojing, DANG Dongsheng

2015, 48(2):  117-121.  DOI: 10.11930.2015.2.117

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To meet the requirements of centralized integration of large scale wind power on the economy and security of transmission network expansion planning, a general scheme is proposed for establishing the transmission network expansion planning platform with large scale wind power integration. By applying the transmission network optimization planning theory which considers the risk and economy, an integrated information management and transmission network expansion planning system is developed, which has such functions as power fluctuation analysis of wind farm group and transmission capacity. optimization, collection and management of historical power output data of in-service wind farms, information processing of proposed wind farms, and comprehensive evaluation of the optimal planning. An evolution model is constructed and an practical wind power output forecasting method of wind farm groups is proposed based on the historical wind power output, and a comprehensive transmission network evaluation index system is also established, which can provide an effective technical support for intensive data analysis, high accurate output forecasting, precise scheme assessment and global management of transmission network expansion planning.

Study on the Impacts of Short-Term Demand Response on Generation Expansion Planning withWind Power

LI Wenpei, FANG Hualiang, MA Xiyuan, LIU Kai

2015, 48(2):  122-127.  DOI: 10.11930.2015.2.122

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The randomness and intermittence of wind power make the cost of electricity generation increase greatly and exacerbate the imbalance between supply and demand. In the electricity market environment, the demand side has the ability to respond to the variations of energy price in short term, which can help the power grid to absorb wind power. Based on this feature, a generation expansion planning model which incorporates wind power and short-term demand response is established in this paper. The elasticity of own-price and cross-price, the constraints of CO2 emission intensity and the wind power reserve capacity are also taken into account. Moreover, through simulation, the power generation capacity is obtained. The experimental results not only validate the rationality of the model, but also prove that the introduction of demand response can increase the wind power penetration and reduce the cost of power supply.

Transmission Expansion Planning Method With Consideration of Demand Side Management

LIANG Wenju, LIU Huayong, CUI Rong, TANG Wenzuo, HU Zechun

2015, 48(2):  128-131.  DOI: 10.11930.2015.2.128

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With the increase of power load demand and the growing scarcity of transmission line corridor, the demand side management (DSM) has become an important way to reduce or defer the investment on power grid and power generation. In this paper, the influence of the peak load on DSM is analyzed through load duration curve and a modeling method is proposed for DSM in the procedure of transmission expansion planning(TEP). Then, a TEP mathematical formulation is built with consideration of DSM and total investment constraint. The formulation is a mixed-integer linear model which can be solved by optimization software. A case study is made to quantitively analyze the effects of DSM on the transmission planning schemes and the result has proved the effectiveness of the DSM in reducing the TEP investment.

Research on Support Ability of Installed Thermal Power in Henan Province

BAI Hongkun, LI Gansheng, NIU Zhongmin, WEI Yingxu, SI Bingjin, XU Yi, WANG Yuxin

2015, 48(2):  132-138.  DOI: 10.11930.2015.2.132

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Although Henan is a province with rich energy resources, it has become a net energy import province since the late years of the “Eleventh Five-Year Plan(2006-2010)”. An analysis of the resources and their support ability in Henan Province shows that the coal resources play a decisive role, and the range of the upper limit of the installed thermal capacity that the resources can support is thus determined. It is proposed that in order to promote the sustainable energy utilization, the coal and water resources and the environmental capacities outside the province should be fully utilized and the proportion of the imported power shall be increased through utilizing the existing and planned coal transportation channels. The study results of this paper can provide a reference for formulating the medium-and long-term energy development strategy of Henan Province.

Technology and Economics

Economy Evaluation and Development Suggestions for Distributed PV-Energy Storage System in China

LYU Shuanghui, CAI Shengxia, WANG Shouxiang

2015, 48(2):  139-144.  DOI: 10.11930.2015.2.139

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According to the current policy of distributed photovoltaic(PV) and energy storage development in China, the economic evaluations of the distributed PV system and PV-energy storage system (PV-ESS) are made with the suggestions for PV system development being put forward. Firstly, given the PV-ESS structure and its system operation mode, the economic model of PV-ESS is established. Then, based on the sunshine condition in Tianjin, the PV output power curve is obtained and the economies of distributed PV and PV-ESS are evaluated and compared under the tariff modes of flat rate tariff and time-of-day tariff for different customers with different load curves. The results show that the cost of PV system and energy storage system, the tariff mode and the load characteristics are the major factors that influence the economy of PV-ESS development for different customers. At last, the suggestions are given for PV and PV-ESS promotion and development from the aspects of cost reduction, time-of-day tariff implementation and user classification.

Study on the Relationship Between Urbanization Process and Electricity Demand Growth

XIAO Xin，, ZHOU Yuhui, ZHANG Ning, HAN Xinyang, XUE Wanlei, TANG Xin, YIN Li

2015, 48(2):  145-149.  DOI: 10.11930.2015.2.145

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This paper analyzes the influencing mechanism of urbanization process to electricity demand, studies the development law of urbanization rate and electricity consumption of domestic and foreign major countries. It summarizes the characteristics of the periodic growth of electricity demand in urbanization process, and proposes that there is a high positive correlation between urbanization and electricity demand growth. Then, this paper analyzes the correlation between China’s industrialization, urbanization, marketization, internationalization with electricity demand, finding out the highest correlation between urbanization and electricity demand. Thirdly, this paper builds a model for the relationship between urbanization process and total electricity consumption growth of China, proposing that there’ll be average 4.6% growth in total electricity consumption for each 1% increase of urbanization rate in the future increase from 50% to 75% of urbanization rate, and when the urbanization rate surpasses 75%, electricity demand growth will slow down. It also builds models for the relationship between urbanization process and electricity demand of Tianjin City, proposing that there’ll be average 8.8% growth in total electricity consumption and 890 000 kW increase in power load for each 1% increase of urbanization rate in the future increase from 80% to 90% of urbanization rate. Lastly, this paper gives recommendations that as China’s new round of promoting urbanization, relevant departments should pay more attention to the corresponding planning and construction of power generation and grid facilities and pay special concern to changes in spatial load caused by population transfer from countryside to cities and towns.

Research on Corrosion Protection Life-Cycle Cost of Transmission Steel Towers

YUE Zengwu, LI Xingeng, FAN Zhibin, GUO Kai

2015, 48(2):  150-155.  DOI: 10.11930.2015.2.150

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An investigation is made on the corrosion protection of the transmission steel towers, such as the initial corrosion protection maintenance time, the maintenance intervals and maintenance cost. The corrosion resistance and cost of hot-dip galvanizing and thermal-spray Zn-Al-Mg-RE alloy coatings are compared in this paper. Based on the investigations and tests on two corrosion protection methods, the total life cycle (40 years) cost (LCC) of corrosion protection for transmission steel towers is calculated. It is concluded that the total LCC of hot-dip galvanizing is low for small lattice towers, while the total LCC of thermal-spray is low for large lattice towers and tube towers.

Forecast of Industrial Output Value Based on Power Consumption

LIU Maomao, FANG Yanjun

2015, 48(2):  156-160.  DOI: 10.11930.2015.2.156

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Power industry is the basic energy sector of national economy and plays an important support role for development of other industries. This paper studies the forecasting method of the output value of industrial enterprises above designated size in terms of power consumption. Based on the data of power consumption and output value of nearly 40 000 industrial enterprises above designated size, the forecasting model is built by the support vector machine optimized by particle swarm optimization (PSO-SVM). By using the data from January 2010 to July 2013 as the training sample of SVM, a forecasting and testing is made on the data from August 2013 to December 2013 and a comparison is also conducted between conventional SVM model and BP Neural Networks model. Result of the simulation shows that the PSO-SVM model can be more accurate and reliable than both SVM model and BP model in forecasting the industry output, and the forecasting method of industry output based on power consumption is scientific and feasible.