Table of Content

23 December 2013, Volume 46 Issue 12

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Power System

Comparison of Strength Reduction Factor Caused by Local Stability of Axial Compressive Members of Transmission Towers in Design Codes

HAN Jun-ke, ZHANG Chun-lei, LI Zhen-bao

2013, 46(12):  1-5.  DOI: 10.11930/j.issn.1004-9649.2013.12.1.4

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By taking the strength reduction factor caused by local stability of axial compressive members of transmission tower as the research object, this paper introduces the strength reduction factors of axial compressive members specified respectively in the standards of Design of latticed steel transmission structures ASCE10-97, Lattice towers and masters BS 8100-3 and Overheard electrical lines exceeding AC 45kV EN 50431-1, and makes a comparison with the Technical regulation for design of tower and pole structures of overhead transmission line DL/T 5154. The results show that: the ratio of b/t is determined by the flat width divided by the thickness of leg in DL/T 5154 and ASCE 10-97, while in BS 8100-3 and EN 50431-1 it is determined by the ratio of the nominal width and thickness of leg; the strength reduction factor with consideration of local stability is determined by reducing the design stress of steel in DL/T 5154, while in ASCE10-97, BS 8100-3 and EN 50431-1 it is determined by reducing the minimum yield stress of steel; the strength reduction factor of the hot rolled angle section members is largest in DL/T 5154, second in ASCE10-97, third in EN 50431-1 and smallest in BS 8100-3.

Line Selection of HHT Detection for Small Current Grounding Fault Based on Compressed Sensing

ZHANG Jie, BI Gui-hong, CHEN Shi-long, XIE Jia-wei

2013, 46(12):  6-6.  DOI: 10.11930/j.issn.1004-9649.2013.12.6.0

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A new signal processing method- the compressed sensing theory is applied in the line selection of small current grounding fault. Each line’s zero sequence current within 1/4 cycle before and after the fault is sampled at lower frequency with the method of compressive sampling, and then the original fault current is accurately reconstructed for the sampled signal. After denoised by wavelet, the reconstructed signal is decomposed by the empirical mode decomposition method(EMD) to get the highest IMF component. Based on the principle that the polarity of the highest IMF component’s first order difference of fault line’s zero’s sequence current is opposite to that of the normal ones at the moment fault occurs, the faulty one is selected. Matlab simulation shows that this method is not restricted by sampling frequency and the results have high accuracy.

Research on Attenuation and Distortion Problems of Lightning Overvoltage

CHEN cong-cong, ZHANG xiao-qing

2013, 46(12):  12-15.  DOI: 10.11930/j.issn.1004-9649.2013.12.12.3

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With consideration of the impact corona and the earth impedance caused by skin effects, the attenuation and distortion problem of lightning overvoltage along the overhead lines is studied in this paper. The impact corona and the earth impedance are firstly discretized and linearized, and then the corresponding parameters are calculated. This calculation method is not only simple in algorithm, but also applicable to engineering practice. In the end, a transmission line model is established with PSCAD software. Through modeling the lightning current hitting on the tower top and the resulted back-flashover, the lightning surge waves were measured at the same point under different conditions for comparison and the lightning withstand level was also measured. This modeling method can reflect the effects of corona and skin effects on wave accurately and intuitively and can be a good reference for system design and engineering practice.

Effect of Power System Voltage Regulator on Voltage Stability of Zhejiang Power System

CHEN Xin-qi, SUN Wei-zhen, ZHOU Yi-fen, CHEN Zhang-wei, HUANG Hong-yang

2013, 46(12):  16-19.  DOI: 10.11930/j.issn.1004-9649.2013.12.16.3

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Brief introduction of power system voltage regulator(PSVR) control theory, the quantitative method of continuation power flow analysis of improved PSVR on static voltage stability of Zhejiang power system, then the sudden increase of load method and trajectory sensitivity analysis method for quantitative analysis of improved PSVR on transient voltage stability of Zhejiang power grid. The calculation results show that, whether it is from the system static voltage stability and transient voltage stability of power system, the power system voltage regulators are conducive to system voltage stability.

Study on UPFC Power Flow Control Model Based on PSASP/UD

LI Chuan-dong, LIN Yin

2013, 46(12):  20-23.  DOI: 10.11930/j.issn.1004-9649.2013.12.20.3

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A decoupling UPFC power flow control model is established in this paper, which is adaptive with Power System Analysis Software Package(PSASP). On the series side of UPFC, the q-axis and d-axis components of the series-injected voltage are used to control the active and reactive power of the transmission line, respectively. On the shunt side of UPFC, the q-axis component of the UPFC shunt current is used to control the bus voltage of the UPFC-connected point based on the instantaneous power theory. The UPFC power flow control goals are achieved by regulating the injection current of the buses where UPFC is embedded into the system. The established power flow control model is applied to a 500 kV power grid and the calculation results verify that the model is accurate and feasible and can be used for engineering research and analysis of practical power grids with UPFC.

Interaction Index Parameters of AC-DC Hybrid Transmission Systems

CHENG Dao-wei, DAI Shi-rong, WU Li-hui

2013, 46(12):  24-28.  DOI: 10.11930/j.issn.1004-9649.2013.12.24.4

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The HVDC multi-feed systems have been formed in South China Power Grid, East China power grid and Sichuan power grid. The existing multi-infeed interaction factor (MIIF) and multi-infeed short circuit ratio (MSCR), however, do not consider the interactions of converter stations in the AC-DC hybrid transmission system and the reactive losses of converter stations. With consideration of the interactions of all converter stations and their reactive loss in form of complex power, the complex power multi-feed short circuit ratio(CMSCR) is proposed in this paper through extending the existing MIIF and MSCR to the AC/DC parallel multi-feed systems. It is proved that the strength of grid system is not only related to the power grid’s structural parameters and DC power variations, but also affected by the bus voltage of the converters. Simulation case study indicates that the CMSCR can characterize, to some extent, the anti-voltage drop capability of the converter buses and is more suitable for practical studies. Moreover, it can offset the deficiency of existing short circuit ratio(SCR) for not considering the reactive influences which often lead to over optimistic evaluation results, and is helpful for AC-DC interconnected power grid stability analysis and planning.

Application of Ultrasonic Partial Discharge Detection in GIS Withstand Voltage Test

JIA Zhi-jie, CHEN Shao-qing, CHEN Hong-bo, LI Jing, GAN De-gang

2013, 46(12):  29-32.  DOI: 10.11930/j.issn.1004-9649.2013.12.29.3

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The AC withstand voltage test and partial discharge(PD) detecting of 500 kV GIS is one of the most important tests before the commission and operation of ±800 kV Jinping inverter station. The ultrasonic PD test system with multi-sensor and wireless transmission is adopted for PD detecting test to overcome the problem caused by numerous GIS partition. A detail elaboration is made in this paper of the field application of the ultrasonic PD detecting in 500 kV GIS AC withstand voltage test of Jinping inverter station. The testing result shows that the ultrasonic PD detecting is good for accurate fault location. Meanwhile, the paper introduces the air chamber types of defects which are prone to occur during transportation and installation of GIS.

Electricity Trading Online Closed-Loop Control Mode and Application

YANG Jian-hua, BAI Shun-ming, YE Ze, LUO Zhao-chun

2013, 46(12):  33-37.  DOI: 10.11930/j.issn.1004-9649.2013.12.33.4

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Currently, transaction-based power management system platform transaction management specialization and standardization work has begun to enter the operational phase. In this paper, combined with the actual situation of central China power transaction management, power trading on the current line of the closed-loop control of the basic model are analyzed, and through the central area of abandon of the beforehand control power trading practices illustrate the model application condition and effect. This paper argues that, in view of different transaction types and different control objectives, selectively uses the pre-control、 in control and ex-post control three modes, according to the management and control model of application conditions and mechanism using three modes and combinations thereof, and it is an effective way to improve the transaction management efficiency and achieve transaction control.

Probabilistic Assessment Method Considering Cascading Failures for Power System

Transient Stability

2013, 46(12):  38-42.  DOI: 10.11930/j.issn.1004-9649.2013.12.38.4

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A series of research results on DSR(dynamic security region) provide convenient conditions for application of the analytical method in probabilistic assessment of transient stability. For heavy load grids, a DSR-based probabilistic assessment method considering cascading failures is proposed in this paper for power system transient stability. For the initial power line fault that may have significant impact on system security, based on the probability characteristics of the instability and overload protection, alternative solution of the transient stability and flow distribution is conducted to get the line’s most likely path which may cause cascading failures. And then the line's probability security index is obtained with consideration of the instability caused by cascading failures. Finally, a test is carried out on the IEEE 10-generator 39-node system to verify the effectiveness and rationality of the proposed model.

Generation Technology

Analysis and Assessment on Effect of Long-Term Oxygenated Treatment for 1 000-MW Ultra Supercritical Units

CHEN Yu-zhong, HUANG Wan-qi, LU Huai-tian, SUN Wei-peng, CAO Song-yan

2013, 46(12):  43-47.  DOI: 10.11930/j.issn.1004-9649.2013.12.43.4

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In this paper the effect of oxygenated treatment(OT) for boiler feedwater of Unit 2(a 1 000-MW ultra supercritical unit) at Huaneng Haimen Power Plant is summaried and analyzed. Since OT is used for the unit, the iron concentration atthe economizer inlet and in the high-pressure heater has been reduced to less than 1 μg/L, and decreased by more than 80% of that of all volatile treatment (oxidation) (AVT(O)), which effectively inhibits flow-accelerated corrosion in the feedwater and high-pressure heater drainage systems, reduces the iron transport and lowers the scaling rate in the economizer and on the water walls. The long-term operating experience shows that OT can not only slow down the boiler pressure dropping rate and avoid blocking of the drainage water control valve for the high-pressure heater, but also increasethe periodic water output of mixed bed in the condensate polishing system from 80 000 tons to 400 000 ton S, indicating a very considerable result of energy saving and consumption reducing, which is significant in improving the safety, reliability and economy of the unit.

Optimization of Condensate Circuit in 1 000-MW Units

WANG Cheng-liang

2013, 46(12):  48-51.  DOI: 10.11930/j.issn.1004-9649.2013.12.48.3

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In this paper, the analysis on the high power consumption of the condensate pump in the 1 000-MW unit of Huadian Zouxian Power Company is conducted. The major cause is then concluded as the rotating speed of the condensate pump motor inverter reduced to its lower limit in order to ensure the safety margin of the seal water pressure of the boiler feed water pump . Therefore, the booster pump is added to the seal water pipeline and meanwhile, the related control and protection logics are optimized. After such innovation and adjustment, the motor inverter can run safely and economically between 0% and 100% load ranges with the power consumption rate of the condensate pump reduced by about 0.2 percent and the coal consumption rate reduced by 0.7 g/(kW·h), which demonstrates significant economic benefits.

Simulation and Model Validation of Steam Turbine and Its Governing System

SHENG Kai, ZHU Xiao-xing, NI Hong-wei, LIU Fu-ping

2013, 46(12):  52-58.  DOI: 10.11930/j.issn.1004-9649.2013.12.52.6

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Parameter testing and measurement for the steam turbine and its governor is an indispensable part of power system modeling, in which simulation and validation are playing a critical role to ensure correct parameters. Aiming at the issues and difficulties existing in the simulation and model validation, the applied solution methods are studied and a set of software was developed for simulation and validation of steam turbine and its governor’s model. The software can adjust the model and implement the simulation according to the characteristics of actual steam turbine and its governor. In addition, it can also calculate the assessment indices automatically based on the simulation results. Therefore, this software package can greatly reduce the workload of users with the accuracy of simulation and validation guaranteed.

DCS-Based Energy-Saving Automatic Control on Variable-Frequency Circulating-Water Pump

ZHANG Li, ZHANG Yu, LIU Wei-Ping, GAN Zhi-yong, WANG Jian

2013, 46(12):  59-61.  DOI: 10.11930/j.issn.1004-9649.2013.12.59.2

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Based on the DCS system for operating units, a method to realize the automatic control on the energy saving of variable frequency circulating-water pump is introduced. From the viewpoint of automatic control theory, the optimal condenser vacuum and the corresponding operation mode of the pump are obtained through the calculation of real-time condenser clean coefficient with the repeated cycle method. Then by comparison and analysis the implementation plan is determined for the energy-saving automatic control in which the matters needing attention in establishing the automatic control system as well as the issues and solutions in the implementation are proposed in details. Finally, the calculation on a 330-MW cogeneration unit is conducted, which concludes that the power consumption of the pump will decrease by 3 761.6 MW·h after the automatic control is implemented.

Analysis and Identification of Friction Vibration of Turbo-Generator Units

YE Ze-ping, DAI Wei

2013, 46(12):  62-66.  DOI: 10.11930/j.issn.1004-9649.2013.12.62.4

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The axial and radial clearances of turbine-generator units are quite small. Therefore collision and friction will happen in the case of diminishing axial or radial clearances between the rotating and the stationary parts, which will cause unit vibrations. In this paper, the mechanism, occasion and location of the vibration caused by collision and friction are introduced. Through the analysis on the causes and characteristics of the axial and radial collision and friction, the methods for identifying the vibration under different conditions are presented. Finally, measures to prevent the vibration in the manufacturing, installation, maintenance, startup and running of the units are put forward.

Operational Reliability Analysis of Pumped-Storage Units in China

MI Jian-hua, ZHOU Hong, WANG Qi-yuan, WANG Li-ya

2013, 46(12):  67-73.  DOI: 10.11930/j.issn.1004-9649.2013.12.67.6

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Aiming at the quick increase of installed capacity and failures of pumped-storage units in China in recent years and based on the investigation on the operation and management of the units in the main regions, the affecting factors on unplanned outage are analyzed combining with the accumulated reliability data. The factors include the status and origin of the equipment , the technical performance of the main parts and managementlevel. The equivalent availability coefficient and equivalent forced outage rate are also compared with the ones in the foreign units and the analysis on the issues concerning the low ratio in the total installed capacity, the short running time and the problems in the construction and installation is conducted with corresponding suggestions proposed to provide reference for increasing the unit performance.

Installation and Adjustment of Rotor Axial Displacement and Differential Expansion Sensors in Semi-Speed Steam Turbines

HUO Lei, SUN Xiao-long, ZHENG Jun-wei

2013, 46(12):  74-78.  DOI: 10.11930/j.issn.1004-9649.2013.12.74.4

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The rotor axial displacement and rotor differential expansion are the major indicators reflecting the clearance of the rotating blades inside the turbine. The process of solving the problems existed in Unit 1 of HongyanheNuclear Power Plant with axial displacement and differential expansion measuring principles and methods for semi-speed steam turbines is systematically presented, including the large measuring value of the axial displacement sensor, the insufficient installation clearance of the high and medium-pressure rotor expansion sensor and the over expansion of the low-pressure rotors in the warming-up stage. Through the analysis on the operation data and variation pattern of the unit, it is indicated that the installation and adjustment of the sensors are correct, which can provide reliable supervision and protection for the unit.

Discussion on Tower Type of Enclosed Circular Coal Yard Applied in Coal-Fired Power Plants

LI Rong-sheng

2013, 46(12):  79-82.  DOI: 10.11930/j.issn.1004-9649.2013.12.79.3

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The layout and structure of the enclosed circular coal yard of center tower type are discussed. A power plant is taken as an example to describe three coal yard designs including the center tower type one and compare the three designs in the technical and economic aspects respectively. The conclusion is that the center tower type coal yard can be extensively applied in thermal power plants with its simple design, convenient maintenance, low costs and high reliability. At the end, issues regarding the design of the enclosed circular coal yard of center tower type are put forward.

New Energy

Theoretical and Simulation Study on Resistance Variations of Brush and Slip Ring of a Double-Fed Induction Generator

CHEN Tao-tao, MA Hong-zhong

2013, 46(12):  83-89.  DOI: 10.11930/j.issn.1004-9649.2013.12.83.6

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Good electrical contact between the brush and slip ring is the precondition for stable operation of a double-fed induction generator (DFIG). The brush and slip ring resistance is therefore an important indicator for evaluating the reliability of the electrical contact system. By taking a DFIG of 1.5 MW for case study, a quantitative analysis and calculation of the working resistance of the brush and slip ring is conducted with consideration of the cyclical change of the slip ring resistance. By using PSCAD/EMTDC simulation software, the numerical model and circuit model of the brush and slip ring dynamic resistance are established respectively under normal and fault working conditions, and a theoretical analysis of brush current interharmonic is carried out. Through comparing and analyzing the brush current before and after the fault condition based on the FFT transformation, it is concluded that the decreasing rate of the brush current interharmonic component is far smaller than that of the fundamental component before and after fault condition, and the THD of fault condition is much larger than that of the normal condition. This conclusion can provide a guidance for condition monitoring and fault diagnosis of the brush and slip ring system and acts as an available criterion for the operation stability of the system.

Combination of Stator Crowbar and DC-Link Discharge Resistor for Fault Ride-Through (FRT) of DFIG

LING Yu, CAI Xu, WANG Ning-bo

2013, 46(12):  90-94.  DOI: 10.11930/j.issn.1004-9649.2013.12.90.4

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Nowadays, crowbar protection is one of the effective fault ride-through(FRT) methods for a doubly fed induction generator (DFIG). However, the controllability of a DFIG may be lost temporarily. To avoid this problem stator crowbar(SC) protection as an alternative has attracted wide attention. But SC cannot provide the DFIG with desired dc-link voltage. So, a combination of SC and discharge resistor is proposed to improve the capability of FRT of the DFIG. Firstly, the theoretical basis of the SC protection is analyzed in the paper. And then the effect of different SC resistances on the system is investigated, based on which the best SC resistance is determined. Finally, the combination method is detailed and simulation is conducted by using PSCAD/EMTDC to verify the effectiveness of the proposed method.

Analysis on the Capacity Credit of a Wind Farm and its Influencing Factors

GAO Zhong-xu, MAO An-jia, CHEN De-zhi, SONG Yun-ting

2013, 46(12):  95-99.  DOI: 10.11930/j.issn.1004-9649.2013.12.95.4

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The capacity credit of a wind farm is a basic index to evaluate the value of its power generation capacity, and it is also an important reference for location planning of wind farms. An autoregressive moving average time series model is used to simulate the hourly wind speeds. Based on the data of forced outage rate of a wind turbine generator, the reliability model of the wind farm is built. The parabola method is used to calculate the effective load-carrying capacity of the wind farm. The sequential Monte Carlo simulation approach is used to study the capacity credit, which not only facilitates the time series modeling of wind speeds, but also provides accurate frequency assessments of the system. Finally, the proposed method is tested with the IEEE-RTS 79 testing system, and the difference of capacity credits with different reliability indices and their affecting factors are also analyzed.

Evaluation of Wind Power Heating in Facilitating Wind Power Integration Capability during Valley Load Period

WANG Cai-xia, LI Qiong-hui, XIE Guo-hui

2013, 46(12):  100-106.  DOI: 10.11930/j.issn.1004-9649.2013.12.100.6

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With the fast development of wind power in China, grid integration of wind power has been a barrier for wind development, especially during the valley load period in winter. Due to the impact of heat load, wind power curtailment becomes a big problem. In areas such as Northeast China and Northwest China, where heating period in winter is long and the proportion of combined heat generation is high, to use the wind power for heating will help to facilitate wind power integration. This paper introduces the principle and characteristics of wind power heating; analyzes the role of wind power heating in improving the wind power integration capability, and the prospect of wind power heating in China. An case study is conducted to quantify the impact of wind power heating on facilitating grid integration capability of wind power. The result shows that wind power heating does help to facilitate wind power integration, but other measures are still needed to thoroughly solve the wind integration problem.

Method for Wind Farm Cluster Active Power Optimal Dispatch under Restricted Output Condition

WANG Shi-qian, LIN Li, DI Li, YU Lin-lin, TIAN Chun-zheng

2013, 46(12):  107-112.  DOI: 10.11930/j.issn.1004-9649.2013.12.107.5

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Due to the inconsistent development of power grid and wind power farm, as well as insufficient power transmission capability, wind-abandon problem is becoming increasingly serious in China, and no effective solution can be found in a short time. With consideration of large scale wind power base construction in China, a method is proposed in this paper for wind farm cluster active power optimal dispatch under output restriction condition, which is based on the ultra short-term wind power forecasting. In this method, the active power maximization and the line loss minimization are assumed as the objective functions on the condition of output restriction, with power system security, output power of wind farm, frequent turn-on and-off of wind turbines, and the low forecasted power as the function constrains. In addition, the active power loss and short term active power forecasting error are also considered. A case study of a wind farm cluster located in the north-west of China has verified the effectiveness and feasibility of this method.

Energy Conservation and Environmental Protection

Removal and Emission of Pollutants from 600-MW Supercritical Units

WANG Yun-jun, WANG Hong-wei, WEI Ji-ping, GAO Jian-kang, GUO Xiao-min

2013, 46(12):  113-117.  DOI: 10.11930/j.issn.1004-9649.2013.12.113.4

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During the transformation of power generation enterprise and corresponding equipment upgrade, it is inevitable to build large- capacity and high-parameter units on the original site with old small units which were shut down and demolished due to the requirements of this technical reform. The construction of a complete set of high-efficiency electrostatic precipitators and gas purification facilities such as desulfurization and denitrification facilities can significantly reduce the pollutant emissions. Taking the Unit 1 in the transformation and expansion project of Huozhou Coal-Fired Power Plant for instance, the paper introduces the effects of the SCR denitrification equipment, five-field electrostatic precipitator and wet flue gas desulphurization(WFGD) equipment on the removal of NO_x, dust and SO₂ produced during coal combustion. Field tests show that under the full load condition, the NO_x removal efficiency by the A and B sides of SCR is in the range from 70% to 80%, while the dust removal efficiency by the electrostatic precipitator is around 99.85%, and the SO₂ removal efficiency by the WFGD equipment is over 98%, which meet all the present standards related to pollutant emissions from coal-fired power plants. Moreover, in comparison with the demolished four 100-MW units, the total emissions from the two newly built 600-MW units have decreased significantly, which proves that the substitution of small units with large ones can definitely attain the goal of generation increase and emission reduction.

Study on Mathematical Models for Optimization of SCR Catalyst Replacement Cycle and Strategy

LI De-bo, LIAO Yong-jin, LU Ji-dong, XU Qi-sheng, YANG Qing-shan

2013, 46(12):  118-121.  DOI: 10.11930/j.issn.1004-9649.2013.12.118.3

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In this paper, the efficient management of SCR catalyst in coal-fired power plants is studied and the models for catalyst activity forecasting, reactor performance computing and catalyst replacement efficiency estimating are established. These models can be used to study catalyst replacement strategies and evaluate their benefit and efficiency. The performance of SCR reactors is determined by the hierarchy calculation method which summarizes the potential from the first layer of the catalyst to its last layer. The activeness of the catalyst in running and the new catalyst samples tested, and the activeness loss function is obtained, which lays the foundation for catalyst upgrading and benefit evaluation in the practice.

Empirical Study on Key Factors of Carbon Emission Intensity of Power Industry

HUO Mo-lin, HAN Xin-yang, SHAN Bao-guo

2013, 46(12):  122-126.  DOI: 10.11930/j.issn.1004-9649.2013.12.122.4

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The power industry faces big challenges of energy saving and emission reduction while it supplies energy for the fast development of the economy. The paper conducts an empirical study on key factors of carbon emission intensity of the power industry. A factor decomposition model is established with the logarithmic mean divisia index to analyze the impacts of some factors such as the house service rate, the power generation structure, the gross coal consumption rate and the line losses on carbon emission intensity. The empirical results show that the reduction of gross coal consumption rate in positive direction is the main contributor to the accumulative reduction of carbon emission intensity, while the primary cause for the short-term changes of carbon emission intensity is the power generation structure and the other causes are, the gross coal consumption rate, the line losses and the house service rate in descending order.

Technology and Economics

Economic Estimation on Large-Scale Application of Electric Sanitation Trucks

NIU Jun-long, ZHANG Wei-ge, SUN Bing-xiang, YU Qin-lu, BI Tai-wei, BAI Kai

2013, 46(12):  127-130.  DOI: 10.11930/j.issn.1004-9649.2013.12.127.3

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Taking the battery of pure electric sanitation trucks for public service as the study object and targeting at 9-year cost recovery and annual revenue of 11%, the battery operation price is estimated with the method of total investment return rate. Suppose that the charging station is designed with operating capacity for 50 electric sanitation trucks , the charging price is estimated with the same method respectively by assuming the actual operational trucks are 10, 15, 20, 25, 30, 35, 40, 45, 50, and 55. The impact of the scale of running trucks on battery operation price is also analyzed, and then suggestions on popularizing the electric sanitation trucks are put forward.

Design and Application of Rules on Denitration Pricing Assessment and Evaluation

SUN Shuan-zhu, WANG Lin, ZHANG You-wei

2013, 46(12):  131-135.  DOI: 10.11930/j.issn.1004-9649.2013.12.131.4

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In December 2011, the State Development and Reform Commission issued the notice to launch a pilot project on denitration price in Jiangsu and some other provinces. To regulate the assessment and management of the denitration price, a set of rules on denitration price assessment and evaluation is designed by Jiangsu Province. Taking the various denitration principles into full account, the evaluation terms are defined in the rules for each decision conditions. In 2012, the rules were applied in the thermal power plants in Jiangsu, and the average emission concentration of NO_x was reduced from 219 mg/m³ to 77 mg/m³. The results show that the application of the rules has effectively promoted the reduction of NO_x emission. Finally, based on the current practice of the rules and future development trends of thermal power plants, some amendments to the rules are proposed.

Method for Estimating User’s Power Outage Loss Based on Partition Technology

ZHANG Cai-qing, ZHANG Wen-jun

2013, 46(12):  136-140.  DOI: 10.11930/j.issn.1004-9649.2013.12.136.4

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The paper elaborates the concept of power outage loss and its influencing factors. The partition technology is introduced in the paper to segment distribution network and to determine the load point types of every block after fault outage occurs. The outage duration of every partitioned region is determined according to the load point type and the partitioned user’s power outage losses are calculated by the comprehensive user outage loss function. Finally the total users’ outage losses of the system are estimated by summary of the every partitioned user’s power outage loss. Compared with the traditional estimation method, this method is proved to be feasible and effective.

Research on Resource and Environmental Value Oriented Thermal Power Plant Dispatching

LIU Shao-yin, LI Shan-feng, TANG Cong-ming

2013, 46(12):  141-143.  DOI: 10.11930/j.issn.1004-9649.2013.12.141.2

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When making power dispatching strategies on energy conservation and environmental protection for thermal power plants, the interests of different enterprises under the government intervention must be balanced. To realize the tradings in energy saving and emission reduction between the thermal power generation enterprises in one grid by taking advantage of energy allocation by power dispatch and with resource and environmental value in consideration can, balance the relationship of the stakeholders, arouse their enthusiasm, save administrative resources and eventually achieve the goal of energy conservation and emission reduction. In this paper, the compensatory mechanism between thermal power generation enterprises is established and its algorithm is studied.

Power Planning

Transmission Curves Optimization of Sichuan Grid’s Seasonal Electric Energy

CHEN Han-Xiong

2013, 46(12):  144-150.  DOI: 10.11930/j.issn.1004-9649.2013.12.144.6

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In order to take advantage of the strong transmission capability of the SGCC’s three ±800 kV UHVDC transmission lines to increase the outbound delivery of Sichuan’s seasonal electric energy in flood season and reduce water abandon-related power loss of Sichuan power grid, based on an analysis of the water abandon characteristics of Sichuan grid in flood season and the hydrological output features of hydropower stations, it is proposed in this paper to optimize the transmission curves of three ±800 kV UHVDC power transmission lines and increase the delivery power of Sichuan grid to East China Grid in high flow period. The study shows that it can be realized to increase the delivery output of the Sichuan grid’s seasonal electric energy by 5 500 GW·h through optimizing the 3-circuit UHVDC transmission curves in 2015.

Development Planning of Nuclear Power Generation in Eastern China

JIA De-xiang, HAN Jing

2013, 46(12):  151-153.  DOI: 10.11930/j.issn.1004-9649.2013.12.151.2

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The eastern China is short in local energy supply with serious environmental pollution. Generally, the nuclear power generation works at base load, which needs in-depth study about its planning and influence on the power system’s peak load regulation. In this paper, the principles and methods for the planning of nuclear power generation are proposed. Based on the object of minimizing the total system cost of power supply with the requirement of the power system’s construction and operation and the balance of power and energy in consideration, the total scale and structure of the power sources including the scale of nuclear power are studied. Furthermore, considering the progress of preliminary work and the ability of peak load regulation, the capacity of nuclear power is recommended for the area and the environmental benefit estimated. The study can provide guidance for the development of nuclear power generation in eastern China.

Fuzzy Clustering Analysis of Electricity Customers Constrained by Carbon Reduction Quota

WANG Jing-min, WANG Chao

2013, 46(12):  154-159.  DOI: 10.11930/j.issn.1004-9649.2013.12.154.5

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Constrained by carbon reduction quota, the power supply enterprises will have to expand the scope of their customer service from simple power supply marketing to comprehensive guidance for customers to electricity consumption optimization and carbon reduction services. Therefore, considering the carbon reduction level of electricity customers, this article builds a power customer value index system in the low-carbon economy, proposes a new method by taking advantage of fuzzy clustering algorithm to finely classify the power customers, and then analyzes the optimal threshold value under dynamic clustering. Furthermore, a practical analysis on an example case of ten large industrial customers in one city is conducted with this method. The segmentation result shows that this assessment system is proven to be reasonable. Finally, the characteristics of different kinds of customers are categorized, and corresponding recommendations on how to provide pertinent services with the cluster results are put forward.