Table of Content

25 October 2015, Volume 48 Issue 10

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Generation Technology

Study on Unbalanced Vibration Characteristics of 1 000-MW Steam Turbine Shaft Series with N+1 Supports

CUI Yahui, YAO Jianfei, ZHANG Junjie, BIN Guangfu3, QU Fulai, BAI Guangchen

2015, 48(10):  1-5.  DOI: 10.11930.2015.10.1

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Due to the structural particularity of N+1 supported shafting, the unbalanced vibration characteristics of Siemens 1 000-MW steam turbine units are complex, which is likely to lead to vibration faults in practical operation. In this paper, units, the shafting dynamic finite element model is built based on the basic structure parameters of the units by using the finite element method. The critical speeds and vibration modes of the shafting are calculated by numerical simulation., the shafting response at the speed of 3 000 r/min is analyzed by weighting the ten axial balancing locations on the rotor respectively. Then, the sensitivity and rules of the shafting vibrations are obtained by comparing the weights and the locations. The conclusion can help the vibration monitoring and fault diagnoses in the operation process of the steam turbine units.

The Pre-service Inspection of AP1000 Steam Generator Tubes

WANG Hao, SHI Yongjun, GAO Jun, MIAO Yusheng, DING Hongfeng, YU Yi

2015, 48(10):  6-11.  DOI: 10.11930.2015.10.6

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In order to verify the quality of AP1000 steam generator tubes in a nuclear power plant, following the national nuclear safety regulation, ASME Standards Volume XI and Westinghouse design specifications, the pre-service inspection(PSI) should be conducted by adopting eddy current inspection after the hydraulic pressure testing and before loading for the total steam generator tubes. In this paper, the eddy current inspection system, implementation, inspecting technology and inspection results are presented. The inspection reveals that the“DNT” signal is seen in 24 tubes and the“BLG” signal is seen in 23 tubes in the two steam generators, all of which meet the acceptance criteria, and no recordable signals are seen in other tubes. In addition, the comparison between the PSI results and the completion report is carried out, which shows that they are in total consistency.

Economic Analysis on Source Steam Switching of Steam-Driving Induced Draft Fan for 600-MW Indirect Air-Cooling Units

GUO Junshan, SI Fenqi, SHAO Zhuang, ZHU Kangping

2015, 48(10):  12-17.  DOI: 10.11930.2015.10.12

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Taking the steam-driving induced draft fan system of a 600-MW air-cooling unit as an example, the models for small turbine condenser thermal calculation and source steam economic calculation are established respectively. Through the calculation of the economic differences of the steam-driving induced draft fan system using different source steam in different seasons, an optimization method is put forward that the source steam of the small turbine should be changed with the change of the seasons. The calculation results show that the steam-driving induced draft fan system using different source steam has obvious influence on the unit economy, and compared with the fourth stage extraction steam, the net coal consumption rate can be lowered by 0.9 g/(kW·h) when the small turbine is driven by the fifth stage extraction steam in winter and autumn.

Study on Optimal Reservoir Scheduling Model and Power Dispatch Law

LI Kefei, WU Jian, XIE Wei, HOU Baojian, SU Liu

2015, 48(10):  18-22.  DOI: 10.11930.2015.10.18

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The reservoir scheduling chart has already become the guidance for reservoir operating and scheduling thanks to its advantages of being simple, direct and viewable. However, it is hard for the scheduling to achieve optimal results and make full use of reservoirs when operation is performed following the chart. In this paper, aiming at this problem, the model integrating cascade reservoirs with optimized power dispatch is established and solved by adopting dynamic programming successive approximation(DPSA) and dynamic programming (DP) nesting algorithms. Through comparison between the results of scheduling chart simulation and optimized operation, the rationality of the model is verified, and the power dispatch laws in the flood season and the non-flood season are developed by using probability statistics method. The application in the cascade reservoirs of a watershed shows that the optimized operation will achieve better generation benefits, and the power dispatch laws can provide guidance for annual scheduling programming and reservoir operating.

Column of Instrument & Control

Comparison and Experiment Analysis of Two Simplified Load-Pressure Models of Subcritical Units

ZHANG Ruifeng, LI Xiaojun, PAN Hua, TIAN Liang

2015, 48(10):  23-27.  DOI: 10.11930.2015.10.23

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In this paper, the comparison between two simplified nonlinear load-pressure models is conducted for common subcritical units. The theoretical and data analysis show that the difference between the two models, is that the transfer function of load-pressure versus fuel quantity in Model 1 has non-minimum phase characteristics and can preferably fit the pressure difference between drum and throttle pressures. By transplanting the real coordinated control logics into the Matlab software and based on the simulation of the two models, the cotroller parameters are tuned and reset in the real coordianted control system. The result shows that Model 1 outperforms Model 2 substantially, and its control performance is greatly improved compared to the orginal parameters.

Test Study on Energy-Saving Optimization of the Coordinated Control System in Ultra Supercritical 1 000-MW units

GONG Guangzhen

2015, 48(10):  28-32.  DOI: 10.11930.2015.10.28

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In order to exploit the energy-saving potential of the power generating units, based on the analysis on the existing problems of the sliding pressure curves, the optimization test on sliding pressure operation at different unit loads and steam turbine governing valve opening is conducted, in which the correlation curves is obtained between the heat consumption rate, net coal consumption rate, main steam pressure and the unit load. According to the test results, the main steam pressure set values within different load ranges are re-analyzed and then determined. The governing valve opening is maintained at 45% to lower the throttling losses such that the units are operated at the optimal economic condition. Through the optimized adjustment of the sliding pressure operation curves, the net coal consumption rate is decreased averagely by 0.83 g/（kW?h）, and the economic performance under low load conditions is improved, which means that the goal is achieved as expected.

System of Single Row Configuration in 660-MW Ultra-Supercritical Units

WU Zhihui, WANG Lei, NIU Haiming, QI Xiangbai

2015, 48(10):  33-37.  DOI: 10.11930.2015.10.33

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Through the analysis on the characteristics and control requirements of single-row main auxiliary system configuration, a series of reliability-enhanced control optimization schemes are proposed, which include hardware system optimization design, real-time online intelligent diagnosis optimization design, boiler main protection optimization design, interlock protection and thermodynamic measurement redundancy configuration for auxiliary equipments, optimized allocation of I/O measurements, the protection technology for single-row auxiliary equipments and so on. The schemes have been applied in Bulian 660-MW ultra-supercritical units successfully, and significant economic and social benefits have been achieved.

Research and Implementation on Soft Backup Technique for Thermal Power Generating Units

GUI Yishu, SHEN Congqi, XIA Jie, FEI Zhangsheng, WU Zhoujing

2015, 48(10):  38-42.  DOI: 10.11930.2015.10.38

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Distributed control systems(DCS) are implemented in domestic thermal power plants to realize real-time control over the generation units. The main equipments may become inoperational due to DCS failures or improper isolation of on-line maintenance. In this case, generally it is not easy to handle the consequential problems and the accident usually will propagate, causing more severe damages to the power generating units. If there are two different independent control logics in the operation of main auxiliary equipments, of which one is the main control logic in operation and the other is the backup one on standby, the reliability of the auxiliary equipments will be no doubt greatly improved. Therefore, through the study and implementation on soft backup technique in the phase Ⅱ expansion project of Tianji Power Plant, the backup operation on six main draught fans is realized. The movable blades of the six main draught fans can be controlled by the analog control system. It can also be switched to the soft backup control mode. These two kinds of control methods are up and running in different controllers simultaneously, thus the reliability of the analog control system is enhanced.

Object-Oriented Algorithm Design and Application of Bypass Control System for Thermal Generation Units

WAN Wenjun, CHEN Shihe, CHEN Yongkang, HU Kangtao

2015, 48(10):  43-47.  DOI: 10.11930.2015.10.43

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In this paper, through the analysis on the current design technology and applications of bypass control systems, the authors pointed out that the traditional sequential programming design technology tends to complicate the operation process of the bypass control functionality and the system does not have sufficient fault tolerance. Therefore, the object-oriented programming technology is introduced into the whole process control design for bypass systems. Taking the bypass startup process for example, the abstraction analysis on the whole process control is conducted. According to the two important attributes defined, i.e., pressure and valve position, the bypass status is divided into different object regions with the overload methods constructed. Finally, the SAMA diagram of the control system is implemented to illustrate the control strategy. The bypass whole process control is then realized in the DCS control system of a 1 000-MW unit. The operation of the bypass system indicates that by virtue of the object-oriented programming technology, the bypass whole process control system is simple but practical with high fault tolerance and robustness.

Study on DC Power Supply for Thermal Control System of Coal-Fired Power Plants

YUE Jianhua

2015, 48(10):  48-53.  DOI: 10.11930.2015.10.48

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Aiming at the unit tripping events and abnormal operation conditions caused by power supply failure of thermal control system in coal-fired power plants, the analysis on the failure mechanism and reliability of the DC power supply system is conducted. Based on the analysis, the solutions are put forward respectively, in which for the in-service units, special DC switching device is adopted to eliminate the coupling effects of diode on the reliability of DC power supply system, while for the newly built units, the AC system is chosen as the power supply of thermal control systems.

Protection Facilities in Coal-Fired Power Plants

SUN Shuanzhu, ZHOU Chunlei, DAI Jiayuan

2015, 48(10):  54-59.  DOI: 10.11930.2015.10.54

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In order to further enhance the supervision level and pertinence of environmental protection and strengthen the quick reaction capability of environmental monitoring in the power industry, the research and construction of the on-line monitoring system for all-work-conditions of environmental protection facilities in coal-fired power plants are launched in Jiangsu Province. Based on the concept of“All-Work-Condition Monitoring”, the industrial process monitoring technique is introduced into the system for flue gas pollution emission supervision in thermal power plants. The monitoring scope covers all the parameters of desulfurization, denitration and dedusting systems as well as the key parameters of main systems. Also the data update frequency is shortened to a few seconds. In addition, the data anormaly detection model is developed to analyze and evaluate the authenticity and effectiveness of the data so as to improve the data quality. At the same time, the environmental electricity price assessment model is also developed in cooperation with government departments to carry out environmental electricity price settlement work. Currently, this system has been widely used throughout Jiangsu Province. A complete generation-side energy-saving and emission-reduction data center has been built on the system, which provides a solid data support for government supervision departments to timely grasp the situation of the pollutant emissions and the operation conditions of energy-saving and environment-protection facilities of coal-fired units in the province, and to exploit energy-saving and emission-reduction potentials.

Power System

Distribution Scheme for Dynamic Capacity-Increase of the Transmission Section with Considering the Multi-risk of Power Grid

QIAN Hai, WANG Qi, CHEN Xiangyu, HU Jun

2015, 48(10):  60-64.  DOI: 10.11930.2015.10.60

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In view of the decision-making issues related to the distribution of dynamic capacity-increase of transmission section, a distribution scheme optimization model is proposed in this paper for transmission section dynamic capacity-increase with consideration of the multi-risk of power grid. The model developed in this paper takes multi-risk constraints into consideration, which include health risk of power equipment, weather risk and system anomaly risk. The capacity limits of the transformer, breaker and transmission line are determined by capacity-increase calculation model. The proposed distribution scheme can balance the economy and security in power transmission of large power grids and provide a possible solution and technical scheme for dynamic capacity-increase distribution of transmission section. This work is supported by National High Technology Research and Development Program of China (863 Program) (No. 2012AA050209).

Research on Electromagnetic Environment of ±800 kV and ±500 kV Double-Circuit DC Transmission Lines with Different Tower Configurations

LI Lingyan, CHEN Yuan, DU Zhiye, LI Jian, RUAN Jiangjun, HUANG Guodong

2015, 48(10):  65-70.  DOI: 10.11930.2015.10.65

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±800 kV and ±500 kV Mixed-Voltage double-circuit DC transmission lines can be considered for solving the contradiction between growing electricity demand and limited line corridor. However, without previous design and operation experience, it is of great significance to study tower configurations during lines design. The electromagnetic environment of four tower types with corresponding pole arrangements are investigated by upstream finite element method. Indicators such as total electric field and ion flow density at ground level, radio interference and audible noise, minimum line height and line corridor width are calculated. Furthermore, tower size threshold is analyzed and compared based on electromagnetic environment limits. According to comprehensive comparison, optimal tower configuration of ±800 kV and ±500 kV double-circuit DC transmission lines is suggested. The electromagnetic environment of the recommended tower under different operating conditions is analyzed, which can provide reference for engineering practice.This work is supported by National Natural Science Foundation of China(No. 51477120) and National Basic Research Program of China (973 Program) (No.2011CB209404).

esearch on Optimal Phase Sequence of Quadruple-Circuit Transmission Line with Dual Voltage 500/220 kV on Same Tower

PAN Chunping, LIAO Minchuan, WANG Jingyi

2015, 48(10):  71-76.  DOI: 10.11930.2015.10.71

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A number of electrical and electromagnetic indices need to be considered and collaborative optimized when selecting phase sequence for multi-circuit transmission line on the same tower. Targeting on safe and stable operation of power grid, different electrical unbalance indices are discussed first. Mathematic model is established targeting on optimal power transfer efficiency with various voltage and current safety constraints. The optimal and several suboptimal phase schemes are obtained by using enumeration method on 1296 different phase sequences for four circuit transmission line with mixed-voltage. In order to prove the comprehensive feasibility and rationality of proposed optimal phase schemes, electromagnetic environment index, inductive voltage and inductive current index are calculated and evaluated. Typical phase sequence optimization cases of four circuit transmission line with dual voltage 500 kV/220 kV prove the validity of proposed model and algorithm.

Computation of Body Surface Electric Field during Live Working on 1 000 kV AC Compact Transmission Lines

FANG Yaqi, PENG Yong, SU Ziming, TANG Pan, LIU Kai, WU Tian, WANG Linong

2015, 48(10):  77-83.  DOI: 10.11930.2015.10.77

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To ensure live working safety on 1 000 kV UHV AC compact transmission lines, it is necessary to study the influence of electric field to operating personnel. By using finite element method, field strength on body surface at each typical work site during live working on the UHV AC compact transmission lines are calculated, and the distribution characteristic of field strength is analyzed. Safety precautions are proposed according to simulation results. The results show that, the electric field on parts of smaller radius of curvature including head and hands are larger than that of other parts, and electric field of body surface reaches maximum during equal-potential operation. The screen clothes with a shielding efficiency no less than 60 dB meet safety requirements. The research results can provide an effective technical support for the live working safety on 1 000 kV UHV AC compact transmission lines.

Design of the Monitoring System for Hybrid Arc-less High Voltage Direct Current Circuit Breaker

HUA Guoxiang, WEI Xiaoguang, GAO Yang

2015, 48(10):  84-89.  DOI: 10.11930.2015.10.84

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In order to monitor and control the hybrid arc-less HVDCCB, and provide adequate data for equipment selection and fault analysis, this paper firstly introduces the hybrid arc-less HVDCCB which is designed by the State Grid Smart Grid Research Institute. Then a practical monitoring system for high voltage direct current circuit breaker is established according to the required data of the junction temperature of power electronics. The system interface utilizes Labview in the design and can fully record and display the data. In addition, the system can realize the function of high frequency data recording and calculation of the junction temperature of IGBT and diode on line. A series of tests have been conducted to verify the effectiveness of the system.

Analysis and Optimization of Short-Circuit Calculation Method in CSG Based on IEC60909

WANG Haohuai, TANG Bao, LIU Miao, ZHANG Yutong

2015, 48(10):  90-96.  DOI: 10.11930.2015.10.90

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With sustained growth of load and improvement of power-grid, short-circuit current is close to upper limit, which is a key factor to operation security of China Southern Power Grid (CSG). Compared with actual measurement, short-circuit current calculation in existing method is on optimistic side, which brings difficulty to power operation mode arrangement. Based on IEC60909 and GB/T 15544 standard, short circuit current calculation results in CSG are compared with results from methods used in other corporations. The main impacting factors of short-circuit current calculation are analyzed on summer-peak load operation mode of CSG in 2013. With consideration of different requirement including accuracy, conservation and equipment capacity, the improvement measure of short-circuit current calculation in CSG is proposed.

Analysis on the Strain Clamp Fracture of ACCC

LIU Chun, CHEN Hongdong, OUYANG Kejian, TANG Yuanfu, HE Pengfei, LI Wenbo, GONG Jing

2015, 48(10):  97-100.  DOI: 10.11930.2015.10.97

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A structure testing was conducted on the disabled ACCC strain clamp of a 220 kV transmission line. It was found that the line for hydraulic crimping on the aluminum tube was wrongly positioned after crimping, which resulted in local stress concentration, and the assembly quality of strain clamp was not in conformity with the requirements of the specification. A series tests are conducted, including the holding force test of wedge clamp and aluminum tube, the temperature-rise test of drainage board, and the influences of the clamp assembly and the temperature rise on holding force are discussed. It is concluded that the poor installed drainage board with heavy current generates an enormous amount of heat, which decreases the holding force of clamp, and leads to the temperature rise of aluminum tube. As a result, the aluminum tube may break with loading and the carbon fiber composite core rod may fall off from the wedge clamp. The technical requirements for the installation and safe operation of strain clamp are presented.

Safety Evaluation of High Voltage Transmission Lines in Coal Mining Areas

CHEN Zhimei, YUAN Guanglin, SONG Kang, SHU Qianjin, WANG Huigang3, HAN Zhijun3

2015, 48(10):  101-106.  DOI: 10.11930.2015.10.101

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Coal mining subsidence seriously affects the safe operation of the power transmission lines. It is greatly significant to carry out the research on the safety evaluation of high voltage transmission lines in coal mining areas. Taking a mining area as a case, this paper estimates the ground deformation of transmission lines in a mining area based on the theory of mining subsidence. With consideration of different working conditions and load combinations, the anti-deformation capacity of the typical transmission towers is obtained by using the finite element method. On this basis, the safety evaluation of the transmission lines in coal mining areas is conducted and the related treatment schemes are proposed. The research results can provide a reference for the similar projects.

Analysis and Treatment of a 220 kV Main Transformer Winding Fault

GUO Wei, HAN Yuting, XU Xuchu, LI Zhipeng, DING Changsong, WEI Min, QI Jiong

2015, 48(10):  107-112.  DOI: 10.11930.2015.10.107

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This paper introduces the rapid fault locating process of a 220 kV main transformer when a tripping accident occurred, which utilized the oil chromatographic analysis, electrical test and winding deformation diagnosis. Besides, the processing procedure in the factory is also included. Through the in-depth accident analysis, it is found that the ability of the transformer winding to resist the impact of short-circuit current is not only related to the design, manufacturing technique and material selection of the transformer, but also depends on the operation and management. Therefore, it is necessary to optimize the design and type-slection of transformer and improve the operating conditions. Particularly, the necessity of a power outage for winding deformation diagnosis should be determined according to the impact of cumulative frequency and the level of the short-circuit current of the large transformer, which has suffered the impact of short circuit current several times, but has no abnormal operations. The expert argumentation should be carried out when necessary. The necessity of repairing or replacement should be determined according to the degree of winding deformation to prevent the large transformer to operate with trouble.

Distance Section Protection Characteristic Research and Setting Calculation

QU Diqing

2015, 48(10):  113-117.  DOI: 10.11930.2015.10.113

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When 110 kV line distance relay serves as remote backup as YND11 type transformer fault on transformer low side backup,setting impedance is not simply the sum of line impedance and transformer impedance. The capability of distance relay on transformer remote backup and load conservation are analyzed in detail for relays of circular, polygon and circular-quadrilateral combined characteristics. The load conservation coefficient calculation method is summarized for different types of distance relays under different load impedance angles. The field test results show the simplicity and validity of proposed calculation method.

Research on Power System Non-linear Evaluation Indices Based on Shepard Similarity Interpolation

SUN Dayan, QIU Chenguang, ZHANG Yong, LIU Lin

2015, 48(10):  118-122.  DOI: 10.11930.2015.10.118

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It is very important for dispatching operation to obtain the accurate reserve capacity and the power load of transmission lines and transformers of the whole power grid. An evaluation system based on nonlinear function is proposed in this paper. Also, the reserve capacity, district reserve capacity, line and transformer capacity calculation methods are provided. Compared to the traditional linear evaluation methods, the proposed method caters for the time-varying and nonlinear characteristics of power system. Besides, the Shepard similarity interpolation algorithm is deployed to provide the total evaluation indices of the whole power system operation condition. The correctness and effectiveness of the proposed evaluation system are verified by a case study which is based on the practical operation condition in Jiangsu power grid.

Evaluation of the Prefecture-Level Power Grid Based on the Rough Set and Integrated Weighting Method

LI Shunxin, YUE Yunli, LI Jialian, ZHANG Xingping

2015, 48(10):  123-126.  DOI: 10.11930.2015.10.123

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Power grid enterprises provide products with the characteristics of quasi-public goods, it is therefore very important to make a comprehensive and objective measurement of the overall power grid operation conditions. According to the characteristics of power grid enterprises, a power grid operation evaluation system is developed in this paper based on five dimensions including safety and reliability, coordination of the speed and scale, power utilization efficiency, economic benefits and social responsibility. During the evaluation process, the biggest difference-based additive weighting method is used to combine the entropy weight method with the order relation analysis method. The proposed method not only embodies expert professional judgment but also includes objective analysis. The weight of every evaluation index is then figured out. Finally, five prefecture-level power grids in a region are taken for case study.

Information and Communication

The Mapping and Encapsulation of Communication Services for Integrated Supervision and Control System of Smart Substation

WANG Dewen, GE Liang

2015, 48(10):  127-133.  DOI: 10.11930.2015.10.127

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The integrated supervision and control system of smart substation implements unified modeling and data transmission of the station information in accordance with IEC 61850 and manufacturing message specification. The system has ability to access, storage and display of whole station information. Based on analysis of station communication architecture, in order to overcome conformance and scalability problems in existing implementation of communication service interface in station layer, an encapsulation method from bottom real-time communication protocol to hosted abstract communication services is proposed. The proposed method supports object-oriented and cross-platform technology, reduces development workload of the clients in station layer, and provides efficient and convenient communication service for data communication gateways and substation side monitoring unit. The results of conformance and performance testing are given to verify the correctness and feasibility of proposed method.

The Present Situation and Prospect of the Construction of Power Time Synchronization Test Network

LIU Gang, GAO Qiang, XIONG Hongzhang3, TENG Ling, WANG Yang

2015, 48(10):  134-138.  DOI: 10.11930.2015.10.134

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With the development of time synchronization technology, in order to meet increasing electricity industry needs for time synchronization, a number of power time synchronization network pilot projects are implemented in different provinces recently. The time synchronization system structure and present situation of transmission network are introduced. Transmission principle of PTP message protocol over SDH E1 lines in those projects is analyzed. Two network schemes, namely master-slave and master backup, are discussed in detail. Based on field application result, time synchronization network construction proposal and problems that need to be solved are proposed. The discussion provides reference for future planning, design and construction of time synchronization network.

Research on Information Security Protection of Industrial Control System

LI Jiawei, HAO Hanyong, LI Ninghui3

2015, 48(10):  139-143.  DOI: 10.11930.2015.10.139

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Different characteristics between industrial control system(ICS) and traditional IT information system are discussed, and information security risks faced by ICS are analyzed. A corresponding security protection system is proposed from both technology and management aspects. On technical side, it is suggested to employ measures including firewall protection, isolation of engineer stations, system security testing and network monitoring. On managerial side, it is recommended to maintain and update management systems and security technology standards in real time. The proposed security protection system has already been verified by industrial control computer security protection pilot projects in electrical company. The project demonstrates its feasibility and provides reference to IPC security protection in power grid.

Study on Regeneration of Deactivated deNOx Catalyst of Different Types

ZHANG Tao, BAI Wei, XIAO Yuting

2015, 48(10):  144-147.  DOI: 10.11930.2015.10.144

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Regarding the three different types of deactivated deNOx catalysts, i.e., honeycomb, plate and corrugation types, different regeneration processes are adopted respectively. The catalyst characterization is also tested using X-ray diffraction(XRD), X-ray fluorescence spectroscopy (XRF) and the specific surface area analyzer. Then the structure and performance of the catalysts are compared before and after regeneration. The study results show that there is no change in the crystal form of titanium dioxide and the active ingredients such as V2O5 are still highly dispersed. After regeneration, the BET and pore volume of the three type catalysts are improved and the microporous structure is recovered. The toxic elements of K, Na and Fe are removed to some extent. Hence the catalytic activities get improved.

Study on Modification of Ultra-Low SO2 Emission in Coal-Fired Power Plants

LI Xinghua, HE Yudong

2015, 48(10):  148-151.  DOI: 10.11930.2015.10.148

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The government is being more strict on environment protection and in some of the primary air pollution prevention and control areas, the local government and the power generation groups have already launched pilot projects of flue gas ultra-low emission to meet the emission requirements by Emission Standard of Air Pollutants for Thermal Power Plants(GB13223-2011), of which the SO2 emission limit is 35 mg/m3 in the standard state. Based on the current development of desulphurization technologies and the case analysis and studies on the modification schemes of ultra-low SO2 emission from coal-fired units adopting wet limestone/gypsum FGD, the successful applications of different scenarios are presented，and the modification proposals for units using coals of different sulphur contents are suggested.

Design and Application of 130 t/h Circulating Fluidized Bed Boiler Flue Gas SNCR Denitrification Engineering

LIANG Lei

2015, 48(10):  152-156.  DOI: 10.11930.2015.10.152

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By taking the design of a 130 t/h circulating fluidized bed boiler (CFB) SNCR flue gas denitrification engineering in Shaanxi Yulin as an example, this paper introduces the essential modules in flue gas denitrification, which include the desalted water storage and transportation module, ammonia storage and transportation module, compressed air jet module. Besides, the spray module technological process and the selections of the relevant equipment type and material are described. Also, the selection bases for spray gun and the ammonia analyzer position are introduced. Then, the operation cost of SNCR and SCR is compared. The comparison results indicate that the SNCR technique is more suitable to control the NOx emission for small sized coal fired boiler, especially for flue gas denitrification of CFB boiler.

Study on Adsorbents for NOx Adsorption from Flue Gas

ZHAO Yi, WANG Han, WANG Tianhao

2015, 48(10):  157-160.  DOI: 10.11930.2015.10.157

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NOx is the most prevalent harmful gas which is generated from fossil fuel combustion by industries and transportation. It is urgent to decrease the NOx emissions from fossil fuel combustion. Through the comparison of the structural characteristics, NOx absorption capacity, selectivity, reaction characteristics and absorption mechanism among zeolite, activated carbon, metal-organic frameworks, and metal oxide absorbents in the progress of NOx removal, their possibilities and disadvantages of being as NOx absorbents are analyzed. The results provide reference for researching and developing an adsorbent which can realize NOx removal and absorbent reuse in the future.