Table of Content

05 July 2019, Volume 52 Issue 7

Previous Issue    Next Issue

Research on Entanglement Degradation Model in Quantum Communication of Power System

LI Wei, CHEN Lu, LIU Shaojun, FENG Bao, ZHAO Xinjian, YAN Dong

2019, 52(7):  1-5,16.  DOI: 10.11930/j.issn.1004-9649.201806022

Asbtract ( )   PDF (5936KB) ( )  

References | Related Articles | Metrics

Entangled states are the core resources and the information carriers in private quantum communication technology. How to guarantee the entanglement of two-photon states is one of the main problems in quantum private communication. This paper studies the model of quantum entanglement degradation caused by ambient noise in quantum private communication technology based on single mode optical fibers, especially the noise of overhead power optical cables in the harsh environment. The transverse and longitudinal decoherence effects of quantum entanglement induced by ambient noise are discussed respectively from the anisotropy of refractive index and absorption coefficient. The research results will provide a reference for the application of entanglement-based quantum private communication in power system and other harsh electromagnetic environment.

Continuous-Variable Quantum Key Distribution Protocol Based on Post-Selection

YU Hao, FENG Bao, PAN Zichun, ZHUO Wenhe, LI Zhenwei

2019, 52(7):  6-10.  DOI: 10.11930/j.issn.1004-9649.201811052

Asbtract ( )   PDF (3667KB) ( )  

References | Related Articles | Metrics

Compared with discrete-variable quantum key distribution (DVQKD) protocol that has been widely used in power system, the continuous-variable quantum key distribution (CVQKD), which uses continuous variables to perform QKD protocol, has such advantages as simple equipment, high detection efficiency and good compatibility, and has attracted wide attentions. However, the attenuation in the quantum state transmission heavily reduces the propagation distance of CVQKD. In the paper, we present a CVQKD protocol based on post-selection method, which need not any extra single photon source. The results show that the higher probability values are all reserved and amplified by the post selection window function. The proposed method can simplify the implementation of CVQKD and reduce its cost, and can also provide ideas for studying the quantum secure communication schemes in power network.

FPGA-Based Hardware Encryption of Power Line Patrol Drones

LUO Hao, SU Sheng, YANG Hao, LIN Nan, YUAN Chen

2019, 52(7):  11-16.  DOI: 10.11930/j.issn.1004-9649.201903080

Asbtract ( )   PDF (3751KB) ( )  

References | Related Articles | Metrics

Communication of power line patrol UAV is currently protected with frequency hopping. However, malicious adversaries can steal sequence of frequency hopping and control the patrol UAV. In view of the security protection needs of patrol UAV in the process of field inspection, this paper proposes a method for hardware encryption communication and authentication protection based on field-programmable gate array (FPGA). The patrol UAV is equipped with an embedded secure access module (ESAM) using fix encryption. The remote controller gets the symmetric secret key from the management system of patrol UAV. Thereafter, the secret key is embedded in the FPGA-based encryption system, and the communication between UAV and remote controller can be protected with hardware-based encryption. The proposed approach is of hardware encryption/decryption for both UAV and remote controller, and can meet the security protection needs of UAVs with stringent real-time requirement.

YOLO-Based Real-Time Detection of Power Line Poles from Unmanned Aerial Vehicle Inspection Vision

GUO Jingdong, CHEN Bin, WANG Renshu, WANG Jiayu, ZHONG Linlin

2019, 52(7):  17-23.  DOI: 10.11930/j.issn.1004-9649.201812028

Asbtract ( )   PDF (4137KB) ( )  

References | Related Articles | Metrics

Unmanned aerial vehicles (UAV)-based inspection has become an important approach for power line inspection after disaster. However, the current UAV-based inspection is still performed manually for damage assessments, which is not only time-consuming but also poor in accuracy. In this paper a real-time detection model based on YOLO deep learning algorithm is presented to detect the status of power line poles automatically from the UAV vision data after disaster. The data augmentation is performed for collapsed towers to solve the class imbalance problem. To improve the parameters of YOLO, K-means algorithm is used to cluster object frames of pole data. The experimental results show that the proposed model can effectively detect multi-scale towers in multiple environments. The Recall and Intersection-over-Union (IoU) of the improved YOLO are improved, with the mean average precision (mAP) on the test set of 94.09% and the average processing speed of 20 frames per second (FPS) after improving the parameters. Moreover, we tested the simplified YOLO with faster speed, and the average processing speed reaches 30 FPS.

Research on Multi-rotor UAV Intelligent Power Line Inspection Based on Differential Positioning

ZENG Yihui, HE Tong, GUO Sheng, XIONG Yongliang, CUI Yingru, ZUO Jian, LUO Hao

2019, 52(7):  24-30.  DOI: 10.11930/j.issn.1004-9649.201809113

Asbtract ( )   PDF (4143KB) ( )  

References | Related Articles | Metrics

In view of the problems of the poor automation, low standardization, long patrol time and frequent crash accidents of the manual-controlled unmanned aerial vehicle (UAV) power line inspection, a multi-rotor UAV intelligent power line inspection method is developed based on RTK positioning technology to realize automatic UAV power line inspection. Under the support of RTK high precision positioning technology, the method is firstly to carry out manual-controlled UAV power line inspection, and then the automatic power line inspection plan is developed according to the recorded patrol track to extract such information as the precise meridian, latitude, altitude and the camera pitch angle of each aerial shooting point. Aerial shooting is carried out at preset angles along the set trajectory control points for automatic patrol, and the flow process and standardization of UAV inspection are realized. The results of field testing show that the proposed method can accomplish the task of the fixed-point patrol inspection quickly and accurately under the environment of strong electromagnetic field, and it lays a foundation for standardized UAV power line inspection.

An Automatic Recognition and Defect Diagnosis Model of Transmission Line Insulator Based on YOLOv2 Network

LAI Qiupin, YANG Jun, TAN Bendong, WANG Liang, FU Siyao, HAN Liwei

2019, 52(7):  31-39.  DOI: 10.11930/j.issn.1004-9649.201806102

Asbtract ( )   PDF (4217KB) ( )  

References | Related Articles | Metrics

Aiming at the transmission line insulator images obtained by drones or robots, this paper proposes an online recognition and defect diagnosis model of transmission line insulators based on YOLOv2 network. The YOLOv2 network is trained to learn and accurately recognize the characteristics of various insulators under complicated background, and eventually to accomplish the defect diagnosis of the identified insulators of various status by means of edge detection, line detection, image rotation and vertical projection methods. The simulation results of the patrol inspection images of the transmission lines show that the proposed automatic insulator identification and defect diagnosis method can quickly and accurately identify the insulators from the patrol images of the transmission lines and diagnose the defects and their locations of the insulators, which is beneficial to enhance the intelligence inspection level of transmission lines.

Research on Two-Way Interactive Strategy of Electric Vehicle and Power Grid Based on Evolutionary Game

CHENG Hongbo, LI Zhicheng, WANG Xun, ZENG Han, ZHANG Yu, KANG Chen, XIN Jianbo

2019, 52(7):  40-46.  DOI: 10.11930/j.issn.1004-9649.201805114

Asbtract ( )   PDF (5974KB) ( )  

References | Related Articles | Metrics

With the rapid development of electric vehicle technology, the huge number of on-board batteries will become an important resource for the power grid to cut peak load and fill valley. The development of reasonable discharge electricity price will be conducive to mobilizing the enthusiasm of both sides of the vehicle network to participate in the interaction. Based on the evolutionary game theory, an evolutionary game model is established for the benefit equilibrium of electric vehicle users and power supply companies, and the dynamic evolutionary stability process of the vehicle network is studied. The case study results show that the discharge price has a specific response range, and only within this range, both sides of the vehicle network can benefit from it, thus achieving a benign interaction. This study can provide a reference for the power supply companies to formulate discharge electricity prices.

LVRT Control Strategy For DC Microgrids Considering the Characteristics of PV/Storage/Load

LI Yan, WANG Zhan, HUANG Xun, ZHANG Huiyuan, HE Darui

2019, 52(7):  47-54.  DOI: 10.11930/j.issn.1004-9649.201905107

Asbtract ( )   PDF (6874KB) ( )  

References | Related Articles | Metrics

Low voltage ride-through (LVRT) of grid-connected DC microgrid has been driving academic attentions. Firstly, the structure and operation principle of DC microgrids are developed to obtain the analytical expression of DC bus voltage. Secondly, based on different voltage sags and the maximum current limitation of the converter, a hierarchical coordinated control strategy of bus voltage is proposed considering the characteristics of PV/storage/load. Then according to the fluctuation range of bus voltage and the power state of microgrid, operation modes of DC grid unit are adjusted comprehensively to realize LVRT, which can improve the power balance as well as the stability level of DC bus voltage during LVRT. Finally, a simulation example is built on the platform of MATLAB/Simulink to verify the feasibility of the LVRT strategy and the effectiveness of the control strategy on DC bus voltage.

Heat Storage Decoupling Method Based on Coordinated Load Scheduling Model

LEI Yi, LIU Mingzhen, LIN Kaimin

2019, 52(7):  55-62,131.  DOI: 10.11930/j.issn.1004-9649.201711005

Asbtract ( )   PDF (8473KB) ( )  

References | Related Articles | Metrics

In the winter of China's northern area, the heating period of coal-fired units, the dry season of hydropower units and the period of large-scale wind power generation are superimposed, and there exist serious problems of wind curtailment and environmental pollution. The controllable heat storage electric boilers are used in this paper as peak regulation and dispatch resources, in order to reduce the forced output of CHP and get a lower load peak and a higher load valley when it's hard to regulate the peak load, and to increase the wind power accommodation capacity of power grid in winter, and to form a load-dispatching model featuring source-load coordination. The power-heat coupling characteristics of CHP units are firstly studied; and then a heat-power decoupling scheme is formulated for wind power-heat storage compensation, and a multi-objective load-dispatching model is built with the objective of minimizing both the operation cost and pollutant emission of the power system; finally, the corrected multi-objective particle swarm optimization algorithm is used to solve the model, and the diversity of the Pareto set is maintained by using niche method. Case study shows that the proposed dispatching scheme with electric boiler heat storage can effectively promote accommodation of wind power with optimum environmental and economic benefits, and has a very good application prospect.

Consumptive Capacity Research Based on Wind-Solar Hybrid Characteristics

CHENG Linyan, FENG Yanhong, XU Lin

2019, 52(7):  63-68.  DOI: 10.11930/j.issn.1004-9649.201607073

Asbtract ( )   PDF (6259KB) ( )  

References | Related Articles | Metrics

The traditional wind power consumptive method does not adapt to the solution of consumptive capacity in the wind-solar hybrid area, a new method is therefore proposed in this paper to rapidly calculate the consumptive capacity of renewable energy in order to develop and utilize the wind and solar resources in a healthy way. Firstly, based on the existing wind and solar output data of a whole year in North Hebei area, the whole-year wind-solar hybrid output data are obtained according to the planned ratio of wind and solar power; and then, the effective output of wind and solar power in the same hour of a year is calculated; Finally, based on the power system’s peak shaving margin for every hour of three typical days, including the typical day in the summer and winter respectively and the small heating load day, the consumptive installed capacity of wind and solar power per hour is calculated, and the consumptive capacity of renewable energy is obtained through comparative analysis. Through a case study of South Zhangjiakou area in 2019, the effectiveness of the proposed method has been proved.

Research on Cumulative Damage Model of Transmission Tower Based on Typhoon Path Prediction Information

TANG Yi, XU Xiangxiang, CHEN Bin, YI Tao

2019, 52(7):  69-77.  DOI: 10.11930/j.issn.1004-9649.201812026

Asbtract ( )   PDF (4160KB) ( )  

References | Related Articles | Metrics

Strong typhoons may cause physical damage to the transmission towers in the area where it passes, leading to large-scale blackouts. In order to assist the electric power department to accurately predict the risk of tower collapse and deploy anti-typhoon materials in advance, a cumulative damage model of transmission tower is established based on typhoon path prediction information. Firstly, according to the short-term typhoon forecast information of the meteorological department, the risk tower affected by the typhoon is determined by the method of grid division; Secondly, the basic information of the typhoon from the short-term and short-time dual-time scales and the geographical information of the tower are fully combined to predict the cumulative action time and wind speed of the typhoon. Thirdly, a mathematical model of low-cycle fatigue damage is constructed for towers collapsed due to plastic fatigue under unit time, and the improved Poisson formula is used to obtain the fault probability of towers with different typhoon action times, wind speeds and geographical positions. Finally, the minimum load loss of the power grid is calculated using the DC power flow optimization algorithm. Case study has verified the validity and rationality of the proposed model.

Research on Integrated Standardization of the UHV GIL Technology

HE Jie, CUI Boyuan, WANG Hao, ZHANG Pengfei, LI Zhibing, CHEN Shuang, TENG Yun

2019, 52(7):  78-83.  DOI: 10.11930/j.issn.1004-9649.201808169

Asbtract ( )   PDF (3429KB) ( )  

References | Related Articles | Metrics

In order to improve the coordination and systematization of technical standards for the UHV GIL, the integrated standardization theory has been applied in UHV GIL technology field. Based on the status quo of relevant technologies and standards in China, and referring to the research and application of integrated standardization in other industries, the framework of UHV GIL technical standard-complex is constructed by taking the UHV GIL equipment and related process as the working object and through analyzing the related elements, and the contents of four sub-fields in the framework are perfected. In the end, a standard-complex consisting of 45 technical standards is determined, in which 22 new technical standards need to be developed. Suggestions are proposed on the work of standardization.

Non-uniform Pollution Method and Pollution Flashover Characteristics of Transmission Line Insulators

LIU Qin, WANG Yiwen

2019, 52(7):  84-91.  DOI: 10.11930/j.issn.1004-9649.201901006

Asbtract ( )   PDF (7995KB) ( )  

References | Related Articles | Metrics

At present, pollution of insulators in artificial contamination test is done by uniform smearing, but natural pollution, affected by wind, raining, insulator shape, pollution, pollutant particle size and other factors, is a non-uniform accumulation on the insulator surface, and the non-uniform contamination has an effect on the insulator U_50%. Based on a study of the natural pollution characteristics of insulators in multiple regions of a large area, different pollution characteristics of the upper and lower surfaces of different umbrella insulators are obtained, and a non-uniform artificial pollution method is proposed for the upper and lower surfaces of insulators based on the natural contamination characteristics. Non-uniform artificial contamination tests were carried out for the insulators under AC/ DC voltage, and the corresponding pollution flashover curves were obtained. The test results show that the contamination of the insulators by non-uniform pollution method is close to the actual operating conditions of insulators, and the testing results are more accurate and reasonable. It is concluded that the more non-uniform of the contamination on the upper and lower surfaces, the larger the U_50% value is, but the incremental amplitude of U_50% decreases and tends to be saturated. The main conclusions of this paper are of great significance for the optimization of insulator string length and type selection.

Distribution and Demolition of Induced Current in Grounding Wire of ±1 100 kV Long Distance DC Transmission Lines

LI Huiqi, REN Hongxin, GUO Xin, LIU Chengzhi, ZHANG Yongnai, LIU Daping

2019, 52(7):  92-98.  DOI: 10.11930/j.issn.1004-9649.201805142

Asbtract ( )   PDF (3812KB) ( )  

References | Related Articles | Metrics

Transmission lines with certain length are erected nearby the 1 000 kV double-circuit AC transmission lines, and the usage of grounding wires is an effective measure to prevent the safety of the construction personnel from being injured by inductive electricity. It aims at analyzing the induced current distribution of the grounding wires in the construction and the demolition scheme of grounding wires. Based on the ATP-EMTP electromagnetic transient program, a model of the long distance ±1 100 kV Jiquan DC transmission lines parallel with double circuits on the same tower of 1 000 kV AC transmission lines is established. The induced currents in the DC transmission lines in the construction are calculated. The influence of the inter line distance, parallel length, line height and soil resistivity on the induced currents are analyzed. Finally, the corresponding grounding wire removal plan for the demolition sequence of ground wires is proposed.

Performance Analysis on a Solar Aided Coal-Fired Power Generation System with Simultaneous Integration of Trough and Tower Solar Collectors

YANG Hui, DUAN Liqiang, WANG Zhen, LIU Yulei

2019, 52(7):  99-107.  DOI: 10.11930/j.issn.1004-9649.201803131

Asbtract ( )   PDF (4771KB) ( )  

References | Related Articles | Metrics

Due to the increasingly severe fossil energy shortages and environmental pollutions, as a type of clean and renewable energy sources, solar energy has drawn wide attentions and been intensively developed thanks to its benefits of being abundant, easy to use and non-polluting. In this paper, a new solar energy aided coal-fired power generation system is proposed which integrates trough and tower solar field into a typical 1 000 MW coal-fired power plant. Then the topics are analyzed such as the amount of coal saving, the solar-to-electricity conversion efficiency, and the boiler thermal efficiency of this system as well as the economic expense of the new system. From the results the new system has exhibited better thermodynamic performance than the traditional coal-fired power generation system such that the solar energy can be utilized maximally. Under the THA condition, the standard coal consumption rate of the new system is reduced by 9 g/(kW·h). With the increase of the percentage of feed water heated by solar energy, the highest solar-to-electricity efficiency of the new system can rise up to 25.55%. Moreover, the levelized cost of electricity of the solar energy in the new system is 0.81 yuan/(kW·h), lower than 1.15 yuan/(kW·h) of pure solar thermal power station. Apparently the new system has shown better economic performance.

Analysis on Dynamic Characteristics of Solar-aided Coal-Fired Power Generation System under Load Following

LV Peixin, PANG Liping, LI Ming, DUAN Liqiang, YANG Yongping

2019, 52(7):  108-116.  DOI: 10.11930/j.issn.1004-9649.201804066

Asbtract ( )   PDF (4741KB) ( )  

References | Related Articles | Metrics

Regarding a 600 MW sub-critical solar-aided coal-fired power generation unit, the transient simulation software TRNSYS is used to simulate its operating dynamic characteristics under 100%THA, 75%THA and 50%THA conditions on the summer solstice upon the introduction of the solar energy considering daily solar radiation changes. The results show that the operation of the solar-aided coal-fired power generation system under different operating conditions is affected by solar radiation fluctuations. The change of main parameters is closely related to the flow rate. Specifically, the main steam temperature will go higher with the main steam pressure and flue gas temperature down when the solar-aided system is in operation. The solar-electricity conversion efficiency of the solar-aided system will decrease with the load drop. During the load following process, the introduction of solar energy into boiler will cause main steam temperature to rise such that the dynamic water spray desuperheating measures must be taken to maintain main steam temperature and keep the heat exchange balance between the solar side and the boiler side.

Mechanism Analysis and Treatment of Blade Passing Frequency Vibration for Axial Induced Draft Fans in Power Plant

XU Jian, XIA Xiaofei, LI Kailun, ZHENG Jin, WANG Xing, MA Xiang

2019, 52(7):  117-122.  DOI: 10.11930/j.issn.1004-9649.201811102

Asbtract ( )   PDF (4618KB) ( )  

References | Related Articles | Metrics

Based on extensive investigation and literature review, this paper systematically explored the blade passing frequency problem in the axial induced draft fans with the vibration amplitude exceeding the related standards, which has occurred widely in coal-fired power plants after the environmental transformation project implemented. Through the studies on a typical case in a domestic plant, the internal mechanism and treatment processes are analyzed in details. The study result shows that blade tip clearance evenness, casing roundness, blade synchronicity, blade shape consistency, impeller balance, and export flue forms all contribute to this vibration. At last, the treatment plan corresponding to the various causes of the vibration are put forward respectively. The research results and management experience presented are applicable to the blade passing frequency vibration treatment for axial induced draft fans in power plants.

Optimization and Engineering Application toward Energy Saving for Flue Gas Ducts in Large Coal-Fired Power Plants

LI Haoran, XU Yongfeng, MA Xiang

2019, 52(7):  123-131.  DOI: 10.11930/j.issn.1004-9649.201807042

Asbtract ( )   PDF (5120KB) ( )  

References | Related Articles | Metrics

To explore the mechanism of flue gas duct optimization for large coal-fired power plants, by virtue of numerical simulation, the flow fields of a square and a circular cross-section flue gas duct model are calculated and analyzed respectively. The result indicates that, there exists an obvious tail flow eddy zone behind the inner supports in the square cross-section flue gas duct, and the effective flow area of the straight duct is merely 79% of the total cross-section area after the flow is stabilized. The outlet velocity deviation is 0.209 in the square straight duct and 0.246 in the square bend, which shows substantial pressure losses. However, the outlet velocity deviation of the circular flue gas duct is 0.052 in the straight duct and 0.146 in the bend, which means that the flow separation is alleviated in the circular cross-section flue gas duct. Moreover, compared with the square cross-section flue gas duct, the pressure losses are lowered down by more than 60 percent. The numerical calculation of the flue gas duct reconstruction project of a 300 MW power plant shows that after the replacement of original square flue gas ducts with the circular ones and the overall layout optimization, the flue resistance has been decreased by 74.6% and the evenness of the flow fields has been improved. Therefore, great economic benefits have been achieved through the reconstruction project.

Optimization and Operation Research on the Unit Heating Retrofit to Improve Peak-Load Regulation Capability

SONG Chongming, XU Tong, TIAN Xueqin, WANG Xinlei

2019, 52(7):  132-140.  DOI: 10.11930/j.issn.1004-9649.201805184

Asbtract ( )   PDF (5159KB) ( )  

References | Related Articles | Metrics

In the Three-North Areas of China, due to the large amount of installed capacity of wind power and the high proportion of heating units, there has been outstanding conflict between the operations of wind power generators and heating units during the heating season. Considering the large scale of the heating units to be renovated and their future capacity growth, it is of great significance to study the peak-load regulation capability of the heating retrofit unit to promote the sound development of renewable energy absorption and thermoelectric industry. In this paper, the peak-load regulation performance analysis on the retrofit of several mainstream heating units, such as extraction steam retrofit units, high back pressure heating units and coupled heat pump heating units are carried out. The peak-load regulation capability of 300 MW class heating retrofit unit is calculated in the case studies. The optimization of different types of unit heating retrofit is then explored. The case studies show that, the corresponding optimization strategies can effectively improve the system peak-load regulation capability and promote renewable energy absorption with the demand of sufficient heating supply satisfied simultaneously.

An Automatic Potentiometric Titration Testing Method for Active Chlorine Content Detection in the Phosphate Ester Fire-Resistant Fluids

MING Julan, XU Hengchang, ZHONG Hongling, YU Lujing, LI Haiyan, PAN Zhiying, SHEN Xiaoming

2019, 52(7):  141-145.  DOI: 10.11930/j.issn.1004-9649.201811065

Asbtract ( )   PDF (4223KB) ( )  

References | Related Articles | Metrics

The detection of active chlorine content in the phosphate ester fire-resistant fluids is of great importance for the electro-hydraulic control system. In this paper, the principles, instruments and operating conditions of automatic potentiometric titration method to detect active chlorine content in the phosphate ester fire-resistant fluids are studied. The inter-laboratory experiments involving eight laboratories and five samples are conducted and the results are evaluated. In terms of repeatability and reproducibility, limit of detection, recovery rate and accuracy of measurement, the proposed automatic potentiometric titration testing method is capable of detecting the active chlorine content in the phosphate ester fire-resistant fluids with high accuracy and efficiency as well as fast analysis of measurement but simple sample treatment procedures and low requirements for instrument configuration. Therefore it can be promoted for practical usage in the field of power industry.

Study on SNCR Denitration of W-flame Boiler and Its Effect on the Flow Field of SCR Inlet Section

CHEN Haijie, MA Wu, LIU Gongyi, GAO Pan

2019, 52(7):  146-153.  DOI: 10.11930/j.issn.1004-9649.201808094

Asbtract ( )   PDF (4988KB) ( )  

References | Related Articles | Metrics

Because of the high NO_x concentration of W-flame boiler, the coupling denitrification technology consisting of low nitrogen combustion, SNCR and SCR has been applied by several power plants. However, severe violations of the ammonia escape concentration of SCR have taken place in the actual operation since the coupling denitrification technology was carried out. In this paper the effects of boiler load, flow field of urea spray section and ammonia-nitrogen molar ratio on the SNCR denitrification and inlet flow field distribution of SCR were studied for a 600 MW W-flame boiler by numerical simulation and experimental verification. It is found that the non-uniform arrangement of SOFA along the front and rear walls of the boiler is the major cause for the unevenly distributed velocity and temperature fields of urea spray layer. With the decrease of boiler load, the average temperature of reducing agent spray section tends to be close to the optimum denitrification temperature, and the NO_x removal rate increases gradually. The temperature, velocity and NO_x concentration at the inlet section of SCR is not uniformly distributed. Specifically, with the increase of SNCR denitrification rate, the unevenness of NO_x concentration distribution at SCR inlet section intensifies such that the relative standard deviation of NO_x may reach 35%~53% at different boiler loads. Moreover, the usage of SNCR has significant impacts on the NO_x distribution across the SCR inlet section, which may eventually lead to the serious violation of the concentration of ammonia escaping from SCR. To solve this problem, it is suggested to optimize the SOFA arrangement and install new type of gas mixer at the entrance section of SCR.

Application of the RESALT Technology in the FGD Wastewater Concentration Processing of Coal-Fired Power Plant

JIN Yinjia, LIU Zeyu, YOU Liangzhou, XIA Shouqing, TANG Guorui

2019, 52(7):  154-160.  DOI: 10.11930/j.issn.1004-9649.201812121

Asbtract ( )   PDF (4232KB) ( )  

References | Related Articles | Metrics

RESALT technology which is developed based on the Electric dialysis (ED) technology can effectively separate calcium ions from sulfate ions such that the scaling of CaSO₄ is inhibited while the wastewater condensation process can be accomplished at the same time. The experiments were conducted in Huadian Laizhou power company with the inlet flow of the FGD wastewater about 3-4 m³/h. The RESALT equipments were tested to treat three kinds of flue gas desulfurization (FGD) wastewater. The results show that sulfate ions could be efficiently separated from calcium ions and the high salt contained wastewater could also be concentrated at the same time. Since there is no additional chemical agents required for the wastewater pre-treatment, electricity consumption is the main component of the cost during the wastewater treatment process, which will rise as the salt concentration of the wastewater goes up. For example, with the concentrations of 6 480 mg/L of SO₄^2-, 1 820 mg/L of Ca²⁺, 2 462 mg/L of Mg²⁺, 20 680 mg/L of Cl^- and 10 465 mg/L of Na⁺ in the FGD wastewater, the overall electricity consumption rate is 49.5 kW·h per ton and the direct treatment cost is about 22.6 RMB/ton.

Optimization on the Ultra-low NO_x Emission Uniformity and Analysis on the Safety Strategy of SCR Denitration System

QU Litao, LI Chao, WANG Dexin, YU Honghai, DU Jia, QI Xiaohui

2019, 52(7):  161-167.  DOI: 10.11930/j.issn.1004-9649.201807048

Asbtract ( )   PDF (10075KB) ( )  

References | Related Articles | Metrics

In order to keep the NO_x emission concentration and ammonia escape volume within a controllable and stable range after the transformation of ultra-low emission of the SCR reactor, by taking the SCR denitrification system of a 600 MW coal-fired unit as the research object in the case studies, the inconsistency between the data of on-line monitoring (CEMS) measurement acquired from SCR reactor outlet and total discharge outlet is analyzed and investigated in this paper. Through the measurement and testing on the flow distribution at both the entrance and exit of SCR reactor, as well as the concentration field of NO_x and NH₃ with the structural characteristics of SCR denitrification system taken into account, the causes of the problems are explored, then the corresponding optimization and tuning scheme are formulated and the effectiveness of the scheme is verified. The results show that the heterogeneity of the molar ratio of ammonia to nitrogen at the inlet of SCR reactor is the main reason for the uneven distribution of NO_x concentration at the outlet of SCR reactor. Through the optimization and tuning processes, the homogeneity of NO_x concentration distribution at the outlet of SCR reactor is effectively improved, and the ammonia escape volume is reduced as well. The measurement data of the NO_x emission concentration acquired by CEMS from SCR reactor outlet are basically consistent with the total discharge from the outlet of chimney. Meanwhile, based on the curve representing the relationship between NH₃ and NO_x concentration at the outlet of reactor SCR obtained by repeated experiments, this paper proposes both the minimum concentration for safety control and the optimal concentration of NO_x safety-control, so as to facilitate the operation and control of SCR denitrification system in the later stage.

Research on Evolution and Development of Power Generation Scale and Cost under Tradable Green Certificates Market in China

DU Zhendong, XU Erfeng, ZHANG Xiaodi, LIU Dunnan, SHEN Shuyi

2019, 52(7):  168-176.  DOI: 10.11930/j.issn.1004-9649.201706175

Asbtract ( )   PDF (2734KB) ( )  

References | Related Articles | Metrics

Tradable green certificates market is an effective measure to solve the problems of high cost of renewable energy and large funding gap, single funding source and long time period of price subsidy. In order to improve subsidy mechanism of renewable energy and promote clean energy utilization, this paper has a deep research on evolution and development of power generation scale and cost under tradable green certificates market. Economic model of tradable green certificates market is established based on system dynamics and simulation is carried out based on Vensim. Meanwhile, evolution of installed capacity, power generation and unit comprehensive cost of various energy under tradable green certificates market and sensitivity of key factors are analyzed deeply. The results indicate that tradable green certificates market will not only reduce subsidy funds and improve efficiency of subsidies, but also provide a new investment return mode for renewable energy, encourage investment development and effectively promote energy supply side structure optimization with reasonable renewable portfolio standard ratio and tradable green certificates validity period.

Monthly Contract Electricity Compilation Method Based on Wind Farm Operation Characteristics

ZHANG Gaohang, LI Fengting

2019, 52(7):  177-184.  DOI: 10.11930/j.issn.1004-9649.201705102

Asbtract ( )   PDF (2139KB) ( )  

References | Related Articles | Metrics

The monthly contract electricity quantity for power grid is usually compiled using the average decomposition method, but its implementation is difficult for dispatching. A new monthly contract electricity quantity compilation method is therefore proposed based on the operation characteristics of wind farms. On the basis of the rolling correction of the monthly decomposition values of the annual contract electricity quantity, the wind farm operating characteristic indices are established with consideration of the prediction error, output volatility and load-following features of wind power. Considering the constraint range of wind farms' load rates, the monthly contract electricity quantity of each wind farm is worked out. The compilation result can satisfy the constraint of contract electricity of each wind farm, and the operation characteristics of each wind farm is considered in electricity allocation. A case study has proved the effectiveness of the proposed method.