Table of Content

20 July 2016, Volume 49 Issue 7

Previous Issue    Next Issue

Power System

Study on Transient Characteristics of VFTC in 1 100 kV GIS Substation

WEI Meifang, WU Xixiu, YU Guangzhao, TIAN Yun, WU Shipu

2016, 49(7):  1-8.  DOI: 10.11930/j.issn.1004-9649.2016.07.001.08

Asbtract ( )   PDF (1737KB) ( )  

References | Related Articles | Metrics

The very fast transient current(VFTC) occurring in GIS is mainly caused by SF₆ gas discharge due to disconnector operation. This phenomena will not only destroy the insulation of GIS equipment, but also cause a series of electromagnetic interference problems on the secondary equipment. However, current research mostly focuses on very fast transient overvoltage(VFTO) and ignores the effect of VFTC. Transient characteristics of VFTC in UHV(Ultra High Voltage) level are studied. A segment model is adopted in high frequency discharge model of SF₆ based on impedance change in different discharging stages. This new model is applied to simulate VFTC during disconnector operation in a UHV GIS substation. For better understanding the transient characteristics of VFTC, decay time is defined to describe VFTC transient characteristics. Restrain effect of damping resistor on VFTC is also discussed. From research results, VFTC under UHV level has characteristics of high amplitude(up to several thousand amperes), high frequency, broad dominant frequency distribution (0~25 MHz) and long decay time(100 microseconds). The damping resistor can greatly improve VFTC decaying rate, but has small influence on distribution of dominant frequency.

Characteristic Study for Windage Yaw Analysis of V-Shape Composite Insulator String

DANG Huixue, ZHAO Junhai, WU Jing

2016, 49(7):  9-14.  DOI: 10.11930/j.issn.1004-9649.2016.07.009.06

Asbtract ( )   PDF (1644KB) ( )  

References | Related Articles | Metrics

Windage yaw discharge is one of the most disastrous problems for the normal operation of state grid. Accounting for windage yaw problem of V-shape composite insulator string used in Hami-Zhengzhou ultrahigh voltage direct current transmission line, a practical calculation method is developed based on string polygon method for I-shape pan insulator strings. Finite element analysis is used to verify the validation and effectiveness of proposed method. Calculation method of minimum axial tension force determining its application range is also presented. Then windage yaw characteristic study is conducted for Hami-Zhengzhou ultrahigh voltage direct current transmission line, with the influence analysis of mean height of conductors, insulator string angle, horizontal span and vertical span. The results indicate that, with given vertical and horizontal span length, the suggested angle of insulator string increases with the increase of mean height of conductors; with given mean height of conductors and vertical span length, the suggested angle of insulator string increases with the increase of horizontal span length; with given mean height of conductors and horizontal span length, the suggested angle of insulator string decreases with the increase of vertical span length. The suggested angle of insulator string under different conditions are presented.

Research on the Characteristics Extraction of Acoustic Emission Signal from Contaminated Insulator Discharge

TIAN Shuangshuang, JIN Yilin, SHU Naiqiu, SHAO Cuiling, ZHANG Yang

2016, 49(7):  15-19.  DOI: 10.11930/j.issn.1004-9649.2016.07.015.05

Asbtract ( )   PDF (979KB) ( )  

References | Related Articles | Metrics

There are three different modes in the discharge process which include corona discharge, partial discharge and arcing and their characteristics are different. A close relationship is shown between the contamination discharge intensity and characteristics of acoustic emission signals by a large number of tests and studies. Contaminated insulator discharge test was carried out, and a lot of experimental data about acoustic emission signal on contamination discharge was obtained. Based on the experimental data, the extraction method of the characteristics of acoustic emission signals is researched which included energy, the amplitude and frequency. Based on the energy, the amplitude and frequency, the final contamination discharge mode is identified.

Reliability Evaluation of Complex Distribution Network Based on Improved Network-Equivalent and Fault Influence Matrix

ZHANG Jie, WANG Xiaogang, DENG Zhijie, LI Dongqi, CHEN Guokun

2016, 49(7):  20-26.  DOI: 10.11930/j.issn.1004-9649.2016.07.020.07

Asbtract ( )   PDF (1204KB) ( )  

References | Related Articles | Metrics

A new method is proposed for the reliability evaluation of complex distribution networks, which consists of multistage sub- feeders with breakers and protections installed. First, the complex distribution network is simplified into several simple node networks. The upward-equivalent node is connected to the branch switch directly in the improved network-equivalent method.The impact of the superior network on the lower network is treated as an area-node reliability index of the downward-equivalent simple node network,which is added to the reliability indexes in the subsequent computing process. The error of the traditional network-equivalent method is avoided in the improved method. Then a fast method based on the fault influence matrix is derived. The reliability indexes can be calculated using the proposed method. The effect of various switching devices on the system reliability is also taken into account during the computing process. It is not only as accurate as the FMEA method,but faster than the existing algorithms. Moreover, it is easy for programming. Test results are presented to illustrate the effectiveness of the algorithm.

Computation and Comparison for Gust Response of Wires of Transmission Line

ZHANG Donghong, WANG Zhenhua

2016, 49(7):  27-31.  DOI: 10.11930/j.issn.1004-9649.2016.07.027.05

Asbtract ( )   PDF (1851KB) ( )  

References | Related Articles | Metrics

Wind load is the main controlling load in the design of transmission line. The wind load adjustment coefficient is adopted for computing wire load in China’s code. However, the physical meaning of the coefficient is not clear in the code. Based on the wind engineering theory, a formula is deduced for calculating the gust response coefficient of wire, and parameters are chosen to calculate the value. Compared with the coefficients designated in such codes as China’s code, ASCE 74, BS EN 50341 and IEC 60826, the calculated coeffficient with the deduced formula is close to the designated value of ASCE 74, BS EN 50341 and IEC 60826. While the effects of fluctuating wind is not considered in China’s code, the wire wind load calculated according to China’s code is lower than the real load.

A Study on the Characteristics of Wind Load Distribution Coefficient for Transmission Towers Subject to Full-Angle Wind

PAN Feng, YAO Yaoming, HU Wenkan, NIE Jianbo, DAN Hanbo, CHEN Cheng

2016, 49(7):  32-38.  DOI: 10.11930/j.issn.1004-9649.2016.07.032.07

Asbtract ( )   PDF (1158KB) ( )  

References | Related Articles | Metrics

An accurate determination of wind loads is a key element of the transmission tower design. The selection of the wind load distribution coefficient has a direct impact on design specifications of the tower. This paper reviews and analyzes the principles for calculating the wind load on the tower body and the cross-arm in accordance with the design standards. Based on the analysis of the wind load on the tower body and the cross-arm following IEC60826 and BS50341 standards, a calculation formula for wind load distribution coefficient is derived with 0-360 wind angles and the wind load distribution coefficients are calculated for different projected area ratios. In addition, the characteristics of the wind load distribution coefficient of the tower body and the cross-arm are analyzed and compared. Through the research, the characteristics of transmission tower wind load distribution coefficient are developed and the results can be used as references for the transmission tower design.

Comparison on Wind Loads and Wind-Induced Responses of Substation Gantry with Codes of China and Abroad

YANG Mian, SHANG Wennian, LIU Jianqiu, LANG Xujun

2016, 49(7):  39-44.  DOI: 10.11930/j.issn.1004-9649.2016.07.039.06

Asbtract ( )   PDF (1176KB) ( )  

References | Related Articles | Metrics

To improve the internationalization level of China’s substation structural design, a comparison is made on the differences of the wind loads and wind induced responses of the oversea substation latticed gantries calculated by four different design codes, including ASCE 113, BS EN50341-1, IEC60826 and GB 50009. The factors that lead to the differences between these codes are found and the impacts of wind loads of different codes on the gantry design of different voltage levels are analyzed. The wind load formulas in the above-mentioned four codes are all converted into an unified form so that all factors in the formulas can be compared respectively. It is found that the load factor is the crucial factor that leads to the wind load calculated by GB higher than that calculated by other codes. The substation latticed gantries of four different voltage levels are modeled, and the wind loads and wind induced responses calculated by these four codes are compared. The results show that, under the return period of 50 years, the deformation values of the gantry column calculated according to the standard wind load are basically the same between GB and the other codes. However, the forces of the gantry legs calculated according to the design wind load are different between GB and the other codes with the former about 1.14 to 1.37 times higher than the latter, and the difference increases with the increase of the gantry height and voltage levels.

Problems and Solutions of Backup Protection for Large Generator-Transformer Unit

ZHANG Jiankang, SU Xiaohua, JIAO Zaibin

2016, 49(7):  45-50.  DOI: 10.11930/j.issn.1004-9649.2016.07.045.06

Asbtract ( )   PDF (916KB) ( )  

References | Related Articles | Metrics

Compound voltage over-current and zero-sequence over-current protection are usually used as backup protection for phase and ground faults in generator-transformer unit. Since the boundary of protective zone of these two types of protection is difficult to delimit, it frequently leads to miscoordination with protection in grid side. In addition, it is difficult for protection in grid side to coordinate with the protection in power plant side. Both cases can give arise to misoperation of protection at faults. To meet the requirements of speed, selectivity and sensitivity, phase and ground impedance protection are introduced into generator-transformer unit. The setting principle for impedance protection proposed is discussed in detail and a calculation case is given taking a 750 kV power plant as an example. The scheme has been successfully applied to the large generator-transformer unit and its adjacent grid in Northwest China, which greatly improve coordination of backup protection in power plant side and grid side.

Impact of Voltage Controlled DFIG to Wind-Thermal Bundled System Transient Stability

ZHANG Shi, ZHOU Yibo, LI Weiguo, ZHAO Xiang

2016, 49(7):  51-53.  DOI: 10.11930/j.issn.1004-9649.2016.07.051.03

Asbtract ( )   PDF (725KB) ( )  

References | Related Articles | Metrics

Wind-thermal bundled supply system is a vital solution to wind consumption, but heavy power flow on connecting line in wind-thermal bundled system increases system instability during big disturbance. Therefore, it is important to improve transit stability of wind-thermal bundled system. Power system transient stability with voltage control DFIG and fixed power factor control DFIG is analyzed by equal area criterion respectively. Voltage control based DFIG can supply more reactive power to the system, which increase generator voltage, generator power output and deceleration area, and improve system transient stability. Simulation results validate proposed conclusion.

Temperature Forecast for Substation Equipment Based on Optimized General Regression Neural Network

KONG Xuehui, ZHANG Huifen

2016, 49(7):  54-59.  DOI: 10.11930/j.issn.1004-9649.2016.07.054.06

Asbtract ( )   PDF (1078KB) ( )  

References | Related Articles | Metrics

The temperature of substation equipments is an important indicator of device operation condition. Timely equipment temperature prediction guarantees power system operation efficiency and stability. Because of nonlinear and stochastic characteristics of equipment temperature, a generalized regression neural network(GRNN) model is applied to temperature prediction. The optimal soothing factor of GRNN is determined by K-nearest neighbor and multiple rounds of voting. Based on temperature history data of one substation equipment, taken a high voltage switch cabinet as example, a high voltage switch cabinet temperature forecast model is built based on optimized GRNN. The MATLAB simulation results show that proposed model generates better results compare to BP neural network with significant improvement on training speed and prediction accuracy.

Research on Optimum Power Supply Scheme for Beijing Premium Power Park Project

ZHAO Guoliang, CHEN Weijiang, LONG Yunbo, TIAN Xin

2016, 49(7):  60-64.  DOI: 10.11930/j.issn.1004-9649.2016.07.060.05

Asbtract ( )   PDF (1055KB) ( )  

References | Related Articles | Metrics

Based on the technical issues faced by Beijing Premium Power Park(Beijing PPP), one of the 1^st PPPs under construction in China, the methods are studied for classification of power supply quality levels and customized power device configurations in accordance with the current development of PPPs. Finally, a 4-level power supply scheme is proposed for Beijing PPP, which will play a guiding role for the follow-up PPPs in China.

Assessment of Black Start Path Based on Vague and PROMETHEE Method

GAO Wei, ZHANG Bingda, LIN Jikeng, WEI Wenhui, ZHENG Weihong, SHI Chengguang

2016, 49(7):  65-71.  DOI: 10.11930/j.issn.1004-9649.2016.07.065.07

Asbtract ( )   PDF (1175KB) ( )  

References | Related Articles | Metrics

Quick and simple evaluation of black-start schemes is an important topic that has aroused extensive concerns. A complete, multi-attribute evaluation program for black start schemes utilizing combined Vague method and PROMETHEE method was presented. First, the formation of Vague set based on membership and non-membership sets was proposed; then, a new sorting approach for multi-attribute schemes based on Vague method and PROMETHEE method was developed. The proposed new method was applied to the ranking decision of black-start schemes. The initial decision matrix consisting of initial attributes was fuzzed from the perspective of both pros and cons of Vague set. Therefore, the unique feature of each attribute is preserved while all attributes are transformed into the same scale for comparison so that the objective essence of attributes is preserved and fully utilized. The dominant relationship between the schemes was accurately quantified using attribute's preference function, thus a more accurate and credible sorting result was obtained. Evaluation results on real-world power systems demonstrate the effectiveness of the method.

The Medium- and Long-Term Power Demand Forecasting for Jiangsu Province with Consideration of Different Developing Situations

LONG Yu, WANG Xiaoying, ZHOU Qi, JIANG Nan, LUO Xin

2016, 49(7):  72-76.  DOI: 10.11930/j.issn.1004-9649.2016.07.072.05

Asbtract ( )   PDF (1994KB) ( )  

References | Related Articles | Metrics

Different weights of various indicators in different development stages are not considered in the conventional medium- and long-term combined forecasting model, and different development scenarios are not considered either in the medium- and long-term forecasting. Based on the periodicity of economy and its relationship with electric power, the electricity data are grouped according to different development stages, and two indicators including electricity error and trend error are used to calculate the weight of each single model. The entropy method is adopted to get the comprehensive weight of each single forecasting method. With a full consideration of different scenarios of future economic development and changes of electricity technology such as electric vehicle and demand response, a combined forecasting is made respectively for different development scenarios including low-speed development, high-speed development and other factors. The combined forecasting model has been applied to the medium- and long-term power load forecasting of Jiangsu Province and satisfactory results are obtained under different scenarios.

Generation Technology

Analysis on the Application of Reheat Steam Temperature Control Strategy in Ultra Supercritical Units with Secondary Reheat Cycle

ZHANG Jinying, ZHANG Qiusheng, LV Jianhong, HAN Pu

2016, 49(7):  77-81.  DOI: 10.11930/j.issn.1004-9649.2016.07.077.05

Asbtract ( )   PDF (1096KB) ( )  

References | Related Articles | Metrics

Compared with the single reheat units, the thermodynamic system of secondary reheat units is much more complicated. The application of the secondary reheat technology is just started in China with little construction and operation experience. Therefore, it is difficult to choose the regulating scheme for the newly-built secondary reheat unit. In this paper, the reheat steam temperature regulation principle, control strategy and operation results of the newly-built Anyuan 660-MW and Taizhou 1 000-MW secondary reheat units are analyzed in detail, in which the pro and cons of these two typical regulating schemes are presented. Based on the analysis, suggestions are proposed for the selection and improvement of the secondary reheat steam temperature regulating scheme.

Research and Application of Regulation Capacity of Heating Units Based on Big Data

SUN Shuanzhu, DAI Jiayuan, ZHOU Chunlei, WANG Lin, ZHANG Youwei

2016, 49(7):  82-85.  DOI: 10.11930/j.issn.1004-9649.2016.07.082.04

Asbtract ( )   PDF (743KB) ( )  

References | Related Articles | Metrics

Aiming at the complex process and the difficulty of data collection in traditional assessment methods for predicting the regulation capacity of heating units and the urgent requirements for the heating unit dispatch, by adopting the cluster analysis algorithm, the large collections of operating data are divided into several clusters. The Gaussian distribution probability density function tool is used to optimize the regulation capacity according to the preset constraints. Compared with the traditional methods, the cluster analysis algorithm is more concise and since the calculation results come from the large collections of historical operating data, the reproducibility and accuracy of the results are more reliable.

Analysis on Economic Cost of Primary Frequency Regulation of Throttling Steam Turbine Units

FAN Yinlong, ZHANG Bao, GU Zhenghao, QIN Pan, WU Wenjian

2016, 49(7):  86-89.  DOI: 10.11930/j.issn.1004-9649.2016.07.086.04

Asbtract ( )   PDF (740KB) ( )  

References | Related Articles | Metrics

For throttling admission steam turbine units, operation with large regulating valve opening may improve the unit economic performance but lower its primary frequency regulation capability. In this paper, through the test data analysis and the variable condition calculation, the primary frequency regulation performance curve is obtained for the 1 000-MW steam turbine units. In addition, the sliding pressure curve and the valve opening high limit curve which meet the primary frequency regulation standards are also presented. Considering the practical performance test results, the net coal consumption rate is calculated for the operation conditions of qualified primary frequency performance and 45% regulating valve opening. The results show that by improving the main steam pressure and sacrificing some economic performance, the primary frequency regulation performance of the throttling admission steam turbine units can meet the requirements of related standards.

Retrofit and Analysis of Recuperative A-CAES System

HAN Zhonghe, LIU Shiming, ZHOU Quan, PANG Yongchao

2016, 49(7):  90-95.  DOI: 10.11930/j.issn.1004-9649.2016.07.090.06

Asbtract ( )   PDF (1106KB) ( )  

References | Related Articles | Metrics

To cut down the cost of thermal energy storage(TES) medium, the heating compressor is appended to the mineral oil-based adiabatic compressed air energy storage(A-CAES ) system to lower the TES temperature. Furthermore, a novel compressed air energy storage (CAES) system for combined cool, heat and power (CCHP) taking water as the TES medium is proposed. The thermodynamic model of the system is then established such that the thermodynamic calculations are conducted for two systems under designed operation conditions. In particular, the CCHP system performance parameters are computed and compared with the variation of heating pressure ratio (2.4~3.8) and heat exchanger efficiency(0.6~0.9) respectively. The results show that the TES temperature of the CCHP system is significantly reduced with the new water-based TES medium. Compared with the original system, the thermal efficiency and exergy efficiency are improved by about 14% and 2.6% respectively, while the ER remains almost unchanged. In addition, the impact of heating pressure ratio on system performance and exergy losses of the equipments is very minimum while the effectiveness shows significant impacts on system efficiency and exergy losses.

Research on the Application of High Efficient Lignite Coal Power Generation Technology

YU Zhiyun, PEI Yufeng, SHI Dazhong

2016, 49(7):  96-101.  DOI: 10.11930/j.issn.1004-9649.2016.07.096.06

Asbtract ( )   PDF (1096KB) ( )  

References | Related Articles | Metrics

Water resources have become one of the main bottlenecks for the development of coal-fired power plant (CFPP). The construction and development of coal and electricity bases have led to a series of environmental problems, such as intensified contradiction between supply and demand of regional water resources, deterioration of water environment quality and overdraft of groundwater. Thus, To plan and use the limited water resources scientifically by developing water saving technology is a key measure to ease the water resources restriction and realize the sustainable development of coal and electricity bases. A high efficient lignite coal power generation technology is proposed in this paper and has been applied to the national coal and electricity base of Inner Mongolia Xilingol league. It is shown that the technology can effectively alleviate the water resources restraints of CFPP in Xilingol, and can also reduce coal consumption for power generation and the emissions of pollutants.

Video Processing Based Auto-Monitoring Technology for Static Blade Failures of Induced Draft Fans

ZHANG Jiangfeng, YIN Feng, LUO Zhihao, CHEN Xiaoqiang, TONG Jialin

2016, 49(7):  102-105.  DOI: 10.11930/j.issn.1004-9649.2016.07.102.04

Asbtract ( )   PDF (931KB) ( )  

References | Related Articles | Metrics

The induced draft fan of boilers is a major auxiliary equipment in coal-fired power plants, and its operation conditions are critical on the effectiveness of boiler thermodynamic cycle and the safe and stable operation of the plants. The induced draft fan is installed in the boiler flue, where the operating environment is relatively poor, therefore, it is one of the equipments with higher failure rates. On the basis of video processing and with some leading algorithms such as target tracking and state compensation being introduced, this paper proposes an auto-monitoring technology for the static blade failures of induced draft fans power plants. The technology can replace manual inspection and initiate static blade monitoring, thus can effectively avoid the imbalance of power plant operation caused by the not-timely- found static blade failures.

Exploration on Coal Particle Size Control for 600-MW CFB Boilers

DAI Peiji, HU Xiaoxia, LUO Mingxin

2016, 49(7):  106-108.  DOI: 10.11930/j.issn.1004-9649.2016.07.106.03

Asbtract ( )   PDF (508KB) ( )  

References | Related Articles | Metrics

To ensure the good fluidization and sufficient combustion in large CFB boilers, the control over the coal particle size distribution is quite strict. Through the analysis on the issues in the screening system operation of a 300-MW CFB boiler, the optimized design of the two-stage crushing and the three-stage screening is put forward and applied to a 600-MW CFB boiler. The practical operation proves that, based on the design optimization and good maintenance of the crushing and screening system, the coal particle sizes can meet the boiler operation requirements.

Contrastive Study on Lignite Storage

ZENG Bin, QIN Ling, ZHANG Lei, LI Xiaojiang

2016, 49(7):  109-112.  DOI: 10.11930/j.issn.1004-9649.2016.07.109.04

Asbtract ( )   PDF (1009KB) ( )  

References | Related Articles | Metrics

Based on the field storage test on a kind of lignite from Yunnan Province, the indices changes of the coal quality are analyzed, and the linear regression equation representing the changes with time is obtained. Moreover, the optimum storage schemes are proposed based on the evaluation of the economics of the stacking mode of compressed and uncompressed piles. Also, based on the coal oxidation properties and the impact of storage style on the unit energy consumption, the compressed stacking piles are adopted and higher priority in use of the newly-arrived coal is put forward under the premise of ensuring safety.

Study on Design of the Instrument and Control of Super High-Level Water Collecting Natural Draft Cooling Towers for Fossil Fuel Power Plants

TIAN Xiaobing

2016, 49(7):  113-117.  DOI: 10.11930/j.issn.1004-9649.2016.07.113.05

Asbtract ( )   PDF (893KB) ( )  

References | Related Articles | Metrics

Under the background of developing energy-saving and emission-reduction economy advocated by the country, as a new type of natural draft cooling tower(NDCT) featuring outstanding achievements in energy saving and noise reduction, the super high-level water collecting natural draft cooling tower is bound to receive much more attention and applications with its successful commitments in oversea nuclear power stations as well as a domestic 1 000-MW thermal power plant. Different from the conventional NDCT technology, it is unique in its instrument configuration, specification and control philosophy. To take advantage of this technology, from the viewpoint of fossil fuel power plant engineering design, this paper conducts an in-depth study on the instrumentation and control features of super high-level water collecting natural draft cooling towers, and then proposes the engineering design.

New Energy

Site Planning of EV Charging Station by Considering Low Carbon Emission

CHENG Hongbo, XIAO Yongle, WANG Xun, LUN Li

2016, 49(7):  118-121.  DOI: 10.11930/j.issn.1004-9649.2016.07.118.04

Asbtract ( )   PDF (755KB) ( )  

References | Related Articles | Metrics

As a kind of investment, site planning of electric vehicle (EV) charging station should not only consider the minimized operating costs, but also aim to obtain the maximize profit. Based on the emerging technologies, the largest social benefits in saving energy and emission reduction must be included by considering the comprehensive benefits instead of only economic angle. According to this theory, the model of the benefits of emission-reduction has been considered in the site planning of EV charging station. The benefit of environment is particularly emphasized after the charging station being completed. The three affected aspects, which are the legal policy, technical reform and the market, are analyzed. The model of site planning of EV charging station regarding the emission benefit is built. The maximum earnings which contains the benefits of low carbon emission is calculated by the differential evolution (DE) algorithm. The results of simulations and experiments demonstrated that the model of site planning of EV charging station is reasonable and conform to the regional planning of urban and the distribution of the EV rallying point, and also, the effective reference for site planning of EV charging station is provided.

An Analysis of the Power Characteristics of Bidirectional Full-Bridge DC-DC Converter Under Triple-Phase-Shift Control

GU Hongjie, JIANG Daozhuo, YIN Rui, HUANG Shuai, LIANG Yiqiao, WANG Yufen

2016, 49(7):  122-127.  DOI: 10.11930/j.issn.1004-9649.2016.07.122.06

Asbtract ( )   PDF (1089KB) ( )  

References | Related Articles | Metrics

To improve the efficiency of bidirectional full-bridge DC-DC converter, a triple-phase-shift(TPS) control concept is presented base on current dual-phase-shift(DPS) control methodology. This paper analyzes the working principles of the TPS control and the related operating mode of bidirectional full-bridge DC-DC converter. The corresponding mathematical model of the converter is established and the related power characteristics are analyzed. Moreover, the related formulas of the converter under TPS are derived for the convenience of comparative analysis between the TPS control mode and the DPS control mode. The triple-phase-shift control not only retains the advantages of the dual-phase-shift control, but also holds obvious advantages including lower peak current and RMS current, low reactive power, and high efficiency. Finally, a simulation is carried out to verify the excellent performance of the triple-phase-shift control.

The Simulative Research on Energy Management Strategy for Microgrid Structure

CHENG Qiming, CHEN Gen, CHENG Yinman, BAI Yuanfei, LI Ming

2016, 49(7):  128-134.  DOI: 10.11930/j.issn.1004-9649.2016.07.128.07

Asbtract ( )   PDF (1444KB) ( )  

References | Related Articles | Metrics

The control method and the energy management strategy for microgrid are firstly introduced in this paper. Then, the energy management control of microgrid is investigated. The energy management control strategies are also analyzed under islanding condition and grid-connected condition. The PSCAD/EMTDC software is used to simulate the load switching and load variation under islanding condition, as well as the output power changes of each micro power under grid-connected condition. The simulation result has proved the feasibility and validity of the proposed method.

Modeling Analysis of the Influence of the Electric Traction Load Integration on Wind Farms

MAO Guanghui, QIN Rui, HAO Ruhai, YANG Ping, HUANG Baowen

2016, 49(7):  135-139.  DOI: 10.11930/j.issn.1004-9649.2016.07.135.05

Asbtract ( )   PDF (1222KB) ( )  

References | Related Articles | Metrics

Electric traction locomotive generates a single-phase rectifier load which has the nonlinear, asymmetric and large fluctuation characteristics. The stochastic volatility of the numbers of trains within one feeding section and the running status of each locomotive may result in voltage fluctuation of power grid, which will deteriorate the power supply quality. In view of the traction load characteristics of the Lanzhou-Xinjiang second electric railway, which is large in operation density, high in running speed and short in distance to the nearby wind farms, a model simulation is made by using the power system simulation software, including PSASP and ETAP, to analyze the mechanisms for a series of problems such as voltage and frequency deviation, voltage fluctuation and harmonic waves, with the focus paid to the influence of the integration of the traction substation into the power grid on the wind generator units.

Condition Assessment Method of Renewable Energy Generation Equipment Based on Reliability and Generation Performance Indicators

BAI Kai, SONG Peng, DIAO Jia, LI Zhi, ZHANG Yangfan, YANG Weixin, DONG Chao

2016, 49(7):  140-144.  DOI: 10.11930/j.issn.1004-9649.2016.07.140.05

Asbtract ( )   PDF (1028KB) ( )  

References | Related Articles | Metrics

Compared with the conventional thermal power generator units, the renewable energy power generator is small in unit capacity and has little impact on the reliability of a renewable energy power station when a single turbine ceases to operate. It is therefore imperative to pay more attention to the power generation performance of the renewable energy generation equipment in addition to the reliability. A novel condition assessment method is developed in this paper for renewable energy power generation equipment based on the indicators of reliability and power generation performance. And the calculation methodology for the key power generation performance indicators and the requirements for data source standardization are proposed. The proposed condition assessment method has been applied in a national demonstration project of wind power, PV power, energy storage and power transmission to evaluate the condition of generation equipment. Through analyzing the assessment results, the recommended threshold of power generation performance indicators are presented. This method can provide a new technical approach to evaluate the condition of the renewable energy generation equipment.

Low-Carbon Economic Dispatching for Power Grid Integrated with Wind Power System Based on the Green Certificate Trading Mechanism

XU Jiguang

2016, 49(7):  145-150.  DOI: 10.11930/j.issn.1004-9649.2016.07.145.06

Asbtract ( )   PDF (1015KB) ( )  

References | Related Articles | Metrics

In order to promote the development of wind power, the green certificate trading mechanism is introduced into the dispatching model of power system, and a low-carbon economic dispatching for power grid integrated with wind power system is established based on tradable green certificates. In this paper, the environmental cost is introduced to make the low-carbon objective and the economic objective unified. The cost of risk is introduced to cope with the influences of unstable wind power output on the power system. The bacterial colony chemotaxis algorithm(BCC) is used to make an optimization solution of the established model. The results of the low-carbon economic dispatching and the traditional dispatching model are compared and the impact of different green certificate trading levels on system cost and carbon emissions are analyzed. Case study has proved the effectiveness of the established model.

Energy Conservation and Environmental Protection

The Theoretical Calculation of Designed Temperature of Flue Gas in Low-Low Temperature Electrostatic Precipitator and the Existing Problems

SHEN Yanmei, DONG Kun, CUI Zhiyong, WEI Shuzhou

2016, 49(7):  151-156.  DOI: 10.11930/j.issn.1004-9649.2016.07.151.06

Asbtract ( )   PDF (1012KB) ( )  

References | Related Articles | Metrics

Compared with the traditional electrostatic precipitator, the low-low temperature electrostatic precipitator(LLT-ESP) has some advantages in the aspects of energy conservation and environmental protection. This paper conducts a study on the practical application cases of LLT-ESP both at home and abroad, analyzing the differences of their designed flue gas temperatures. The conclusion is that the correct estimate of the gas acid dew-point is crucial for the temperature designing of LLT-ESP. Taking a typical 600-MW coal-fired power plant for example, three widely-used methods are adopted to calculate the acid dew-point with the corresponding accuracy and possible problems being analyzed. In addition, the D/S ratio is calculated to evaluate the device corrosion potential and the feasibility of LLT-ESP. At the end, suggestions on the temperature design of LLT-ESP are proposed, and the possible problems in the LLT-ESP operation when the flue gas temperature being long-term higher than the acid dew point. are analyzed.

Design and Construction of the Experimental Platform for SCR Denitration Catalyst Testing and Performance Evaluation

WANG Kang, ZHU Lin, LIU Tao, ZHUANG Ke, YAO Jie, HOU Shen

2016, 49(7):  157-161.  DOI: 10.11930/j.issn.1004-9649.2016.07.157.05

Asbtract ( )   PDF (964KB) ( )  

References | Related Articles | Metrics

To standardize the SCR denitration catalyst testing and performance evaluation in thermal power plants, by taking the example of the newly-built experimental platform, which is constructed on the basis of the requirements of related standards, this paper analyzes the background of this platform, and puts forward the basis of design and principles followed. Then it presents the technical procedures, platform functionalities, experiment design and, corresponding equipments. Finally the focus and difficulties during the construction process as well as the matters needing attentions are summarized.

The Denitrification Catalyst Abrasion Treatment of a 660-MW Ultra Supercritical Unit

WANG Fangfang, LI Min, XU Peiyao

2016, 49(7):  162-167.  DOI: 10.11930/j.issn.1004-9649.2016.07.162.06

Asbtract ( )   PDF (1610KB) ( )  

References | Related Articles | Metrics

The uneven wear of SCR catalyst may shorten the overall service life of the catalyst in thermal power plants. Taking the example of the SCR device of a 660-MW ultra supercritical unit in a power plant, the causes of uneven catalyst wear are figured out by means of numerical simulation and field tests. The numerical simulation method is also adopted to perform simulation calculation for different retrofit plans such that the optimal solution with even SCR device inlet sectional flow field and particle concentration distribution can be selected and then implemented. The testing result after retrofit shows that the evenness of both the inlet flue gas flow rate and the fly ash concentration are improved, which basically solves the problem of uneven catalyst abrasion.

Performance Assessment and Analysis of Denitration Catalyst in Coal-Fired Power Plant

YAN Min, ZHAO Kai, ZHU Yue

2016, 49(7):  168-172.  DOI: 10.11930/j.issn.1004-9649.2016.07.168.05

Asbtract ( )   PDF (995KB) ( )  

References | Related Articles | Metrics

The performance of the denitration catalyst could affect the efficiency and operation behavior of SCR system directly. In this paper, the exterior appearance as well as the physicochemical and operational characteristics of the denitration catalyst are tested after 28 000-h operation in a coal-fired power plant. The results show that the overall performance of the catalyst is well maintained, but the ratio of its activity to that of fresh one i.e. K/K₀ is lower than the threshold value of the lifespan. In order to satisfy the NO_x discharge up to the standard, the catalyst should be replaced or regenerated in time. Based on these test results, the suggestions on the denitration system optimization and economic operation are proposed.

Technology and Economics

Research of Connection Fee for Specialized Transmission Project Based on Deep Recovery Mechanism

JIANG Yuewen, QIAN Jiaqi

2016, 49(7):  173-178.  DOI: 10.11930/j.issn.1004-9649.2016.07.173.06

Asbtract ( )   PDF (1081KB) ( )  

References | Related Articles | Metrics

According to the current situation of specialized transmission project charges, the investment cost and operation maintenance cost can be repaid by connection and use fees. A novel charge pattern of connection fee considering deep recovery mechanism is proposed from reliability point of view. The pattern considers not only project investment cost, but also extra cost of other user’s reliability in distribution network. The extra electrical equipment expansion cost is caused by connection of specialized transmission project. Depending on node and branch sensitivity coefficient matrix and branch current marginal capacity cost, the locational marginal capacity cost is calculated to evaluate deep cost associated with the connection of specialized transmission project. The proposed method is applied to a practical specialized transmission project. The testing results verify the validity of proposed method.

Study on CCS Investment Decision-Making Based on Compound Real Options for Coal-Fired Power Plant

WANG Xiping, DU Lei, ZHAO Shujun, LI Zhenwei

2016, 49(7):  179-184.  DOI: 10.11930/j.issn.1004-9649.2016.07.179.06

Asbtract ( )   PDF (994KB) ( )  

References | Related Articles | Metrics

Carbon capture and storage(CCS) technology, as an ideal selection for the international community to address climate challenges, has the characteristics of multi-period and uncertainty. With consideration of the phased characteristics of CCS investment decision-making, a two-stage compound real options model is established for CCS investment of coal-fired power plant. Based on the option selection interaction in the phase of demonstration stage and commercial operation stage, and the uncertain factors of carbon prices, fossil fuel prices and investment cost, a two-stage compound real options model is established to evaluate the uncertainty problems in investment decision-making. Finally, a case study is conducted to illustrate the applicability of the proposed model to CCS investment decision-making, and the threshold of carbon trading price under different policy subsidies is obtained, which provides a theoretical basis for CCS investment decision-making for coal-fired power plants.