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Table of Content

    25 July 2015, Volume 37 Issue 7
    Application of Elman neural network in shortterm reservoir inflow forecasting in hydropower station
    LI Qiang,TANG Feng,CHEN Zhuo,HU Chenhe
    2015, 37(7):  1-3. 
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    Abstract:Elman neural network has the adaptability to time varying characteristics, the sensitivity to historical data and the advantage of self learning, it can approximate to any nonlinear mapping by an arbitrary accuracy. Meanwhile, the gradient descent method can make function has properties of monotone decreasing and gradient converges to 0. Compared with the traditional Back Propagation neural network, the method which combining the gradient descent method and Elman neural network has better prediction precision for the short term reservoir inflow forecasting in hydropower station.

    Design of PN300 type distributed controller DPU based on ISaGRAF
    YANG Chunyu
    2015, 37(7):  4-5. 
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    Abstract:DPU PN300 is costomized developed based on ISaGRAF control kernel and VxWorks OS. Using standard programming language, many function blocks and advanced control algorithms were integrated into control kernel. In addition, a monitoring and management module was developed in the DPU. The superior performance of DPU PN300 makes it capable to control a power plant system stably and instantly.

    Research on slidingparameter shutdown technology for unit with Eastern Junggar coalfired boiler
    LI Peng, ZENG Qi
    2015, 37(7):  6-8. 
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    Abstract:The designed coal of the Selfsupply Power Plant of Xinjiang Xinte Energy Company Limited is the Eastern Junggar coal. The preparation before unit slidingparameter shutdown, the parameter control during slidingparameter shutdown and matters needing attention were analyzed. The feasible slidingparameter shutdown technology for Eastern Junggar coalfired boiler was explored. The turbine casing temerature can be reduced quickly and effectively after shutdown by the technology, and this remains sufficient time for unit overhaul.

    A power plant maintenance mode study based on the local power grid environment
    WANG Shenglong1, WANG Jiangyi2, ZHANG Shufang2
    2015, 37(7):  9-14. 
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    Abstract:On the basis of extensive study on common maintenance modes of thermal power plant, a maintenance mode under the local power grid environment was proposed, which is based on the accidental maintenance with the help of complementary advantages and rolling development of coexisted planned maintenance, spot inspection customizing repair and conditionbased maintenance. Meanwhile, a new idea for solving the problems of unscheduled shutdown and maintenance by using generation rights trade model was presented for power generation groups in the future. In addition, this paper suggested that if the power generation groups contract out the spot inspection customizing repair and conditionbased maintenance to other maintenance companies by introducing the market competition,two basic conditions must be satisfied. One is that the contract subject should be separated from the power plant, the other is that maintenance service should be oversupply. In short, this paper provides a new view of reducing unscheduled shutdown and reforming the maintenance modes for local power plants.

    Application of PID predictive control algorithm in large time delay system
    MA Ping, ZHAO Qian
    2015, 37(7):  15-17. 
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    Abstract:For large delay control systems, traditional PID control can not achieve desired control effect, and because of the complex structure, too many parameters, large online computing workload and unclear correspondence between the parameter meaning and actual system, the predictive control method is difficult to be accepted by the engineering staff. Combining the advantages of the PID control and the predictive control, a PID predictive control method was proposed. The method needs less computing workload, it is easy to be used in engineering practice and has better control effect. A simulation research of the method used in controlled object with large delay was carried out. The research result shows that using the PID predictive control method, the control problem of large delay system can be solved effectively, and the system control quality can be improved.

    Structure optimization and dynamic analysis of steering mechanism of tunnel maintenance car
    HU Youan, ZHOU Jun, SONG Ge
    2015, 37(7):  18-23. 
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    Abstract:The working principle of the steering mechanism of tunnel maintenance car was analyzed concretely. Taking the steering moment as research object, based on the genetic algorithm, using the Matlab software, the parameters of the designed trapezoidal steering mechanism were optimized. At the same time, using the large multibody dynamic simulation software ADAMS, the dynamic simulation analysis of the steering mechanism was carried out. The variation curves of various parameters of the steering mechanism in working process (the steering angle and steering moment are included) with time were obtained. The curves were analyzed, and rational improvement proposals were put forward. From the simulation results, the influence of the parameters on the mechanism performance was found, which is useful for selecting optimal parameters and designing more rational steering mechanism.

    Optimization of vacuum pump operation mode of 600MW unit
    HUANG Taiming
    2015, 37(7):  24-26. 
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    Abstract:In the 2×600MW direct aircooled unit of Baiyinhua Jinshan Power Generation Company Limited phase I, there were more vacuum pumps put into operation, which caused high power consumption and large equipment losses. When the unit operates in high back presure, there was a mass of working substance loss. The parameters of the single pump operation, the double pumps operation and the three pumps operation were analyzed. The relation between the vacuum pump operation current and the unit back pressure was clarified, and the optimal operation mode of the turbine vacuum pumps was determined

    Analysis on reason of damage of air preheater lower bearing of 1000MW ultra supercritical unit
    SHAO Changnuan, SUN Weiju
    2015, 37(7):  27-28. 
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    Abstract:The air preheater LAP17286/2250, manufactured by Dongfang Boiler Works  Group Corporation Limited, was selected for the 1000MW unit of China Huadian Corporation. The lower bearing damage fault of the air preheater occurred three times for recent years. The fault was analyzed. Some improvement suggestions were proposed, which include to enhance the manaement of spare cceptance check, to normalize the technical management and others. The unit safe and stable operation was ensured.

    Analysis on reasons of hightemperature corrosion of water wall in supercritical boiler and reformation measures
    SUN Haiyuan
    2015, 37(7):  29-31. 
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    Abstract:Aming at the hightmperature corrosion and lagging of the boiler No.4 in a power plant, the reason of slagging was analyzed, and some reformation measures were adopted, whch include to reform the refractory belt, to adjust the dense and dilute ratio of the richlean separator of the plverizing system,to balance the primary air and to optimize lownitrogen combustion regulating method. After the reformation, the boiler operation parameters can satisfy the tchnical requirements, the slagging in furnace was eliminated, and the safe and economical operation of the boiler was ensured.

    Problems needing attention in electrical design of newbuilt thermal power unit
    TAN Pengzhan
    2015, 37(7):  32-34. 
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    Abstract:There are some problems in electrical design of 300MW and above thermal power units, which include the unreasonable dsign, the high energy consumption and nonconvenience for operation and overhaul. Taking the newbuilt unit of Tianjin Junliangcheng Power Generation Company Limited as example, the problems needing attention in design of the security power, the highvoltage motor, the hydrogencooled generator and the lowvoltage power center were put forward. At the same time, it was pointed out that before construction, the examining of the design drawing must be strengthened, and more attention must be paid to the leavefactory check and acceptance of the equipment for ensuring the unit to operate safely and stably.

    Diagnosis of overtemperature of M701F gas turbine disk and treatment
    XIE Bing, XUE Shaohua
    2015, 37(7):  35-37. 
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    Abstract:After the gas turbine M701F was imported into our country, the over temperature alarms of the secondary stage rotor disk were occurred successively. Based on analysis, it was determined that the reason of the over temperature of secondary stage rotor disk is aging of the gas turbine, which leads the cooling air pressure to be unbalance. The orifices on the secondary vane fixed blade cooling air throttle oriice plate had been enlarged. The temperature of secondary stage rotor disk was reduced sharply, but the unit efficiency and the output power of the gas turbine were decreased somewhat.

    Comparison of ecomonical efficiency of conventional cooling tower and high cooling tower
    LI Yue
    2015, 37(7):  38-39. 
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    Abstract:The general situations of the conventional cooling tower and the high cooling tower were introduced. The economy indexes of the two cooling towers, such as initial investment, the operation and maintenance cost and the cost recovery; were compared and analyzed. The conclusion is that in practical application, the high cooling tower has more advantages and development prospect.

    Analysis of start and stop protection action caused by short circuit of PT secondary circuit
    YANG Qi, ZHAO Lujia, LUO Min, ZHANG Jianjie
    2015, 37(7):  40-42. 
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    Abstract:In a power plant, a short circuit fault of PT secondary loop occurred and caused the generator start and stop protection to act. Based fault seeking, fault treatment and analysis on generator stator grounding principle, it was determined that a short fault occurred in output terminals of PT secondary loop. The method to distinguish the stator primary equipment grounding fault and the secondary loop short circuit fault was given, and relevant suggestions were proposed.

    Accident analysis on maloperation of stability control device as the 110V DC control system is abnormal
    HAN Xianliang
    2015, 37(7):  43-44. 
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    Abstract:In a certain power plant in Guangdong, when the 110V DC control system sounded an alarm, the operating personnel misused multimeter in the process of using stability control device to protect outlet pressing plate, and it caused the running No.1 and No.2 units tripped. This paper analyzed the reason and proposed the corresponding prevention measures and improvements.

    Analysis on reason of steam flow excited vabration of steam turbine and treatment
    QU Bin, ZHANG Yu, ZHANG Li, ZHOU Liansheng, GAN Zhiyong, WANG Jian
    2015, 37(7):  45-49. 
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    Abstract:In the commissioning period of a 300MW unit, abnormal vabration of the steam turbine appeared. The control valve No.2 was closed forcedly, and the vabration was restrained. Based on this, it was inferred preliminaryly that the fault is the rotor instability vibration. Then the vibration test of the unit was carried out, and it was found the vibration occurs in high load condition with half frequency increase and the fault is repeatable. Based on analysis, it was determined that the rotor instability vibration is caused by the shock of the static steam pressure of the nozzle. A rapair plan was drawn up, the load distribution of the bearings was adjusted, the load of the bearing No.1 was enhanced. After the repairing, the unit vibration test was carried out, and the vibration fault had not appear again.

    Analysis on reasons of oil cooler leakage of 1000MW unit host machine
    XING Lijun, LIU Piyuan
    2015, 37(7):  50-51. 
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    Abstract:Taking the 1000MW unit of Huadian Laizhou Power Generation Company Limited as example, the composition of the turbine lubricating oil cooler system was introduced. The reasons of leakage of the oil cooler before and after reformation were analyzed. Relevant treatment measures were proposed, and good result was obtained. But the defects of the design can not be overcome, which needs to sum operation experiences and to improve the design for solving the leakage problem thoroughly.

    The reason analysis on drastic fluctuation of flame detecting signals in swirlopposed boiler and its adjustment measures
    ZHOU Wentai
    2015, 37(7):  52-54. 
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    Abstract:Through analyzing the drastic fluctuation of flame detecting signals in layer D burner for No.62 boiler that is working under low load conditions in Sichuan Guang'an power plant, the reason is considered as the pulverized coal of layer D burner ignition delayed and generated an overlength unburned zone, and consequently influenced the combustion of neighbor layer. Through adjusting the parameters, such as temperature of primary air, fineness of pulverized coal, flow of primary air and secondary air et al., the ignition condition of pulverized coal is improved and the ignition time is shortened,which makes the pulverized coal burnt quickly after entering furnace. After the combustion adjustments, the fluctuation of flame detecting signals becomes normal at low load conditions.

    Analysis on remodelling of belt of tubular belt conveyer
    YANG Caixia
    2015, 37(7):  55-56. 
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    Abstract:In operation of the tubular belt conveyer of the China Huadian Wangting Power Plant, some faults ocurred, which include pipeexpansion, pipe distortion, pipe collapse and off trackng. The influences of the steel cord belt and the polyester core belt on the tubular belt conveyer were compared and analyzed. A remodelling suggestion of the belt No.7b was proposed. The operation status of the tubular belt conveyer after remodelling was traced, and a further improvement suggestion was proposed.

    Application of black start technology in Sabah SPR Power Plant in Malaysia
    BAI Guogang
    2015, 37(7):  57-61. 
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    Abstract:The black start is necessary selfhelp measure of power plant for safety production under powerloss situation in whole plant, and it is also an important measure to protect the power grid to operate safely. The purpose, the requirement and the pass criteria of the black start test in Sabah SPR 100MW gassteam combined cycle power plant in Malaysia were expounded. The operation step of black start test and the matters needing attention were introduced emphatically.

    Research on the antihaze technology of gas turbine inlet system
    ZHU Jinjie
    2015, 37(7):  62-63. 
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    Abstract:This paper briefly introduced the structure and composition of gas turbine inlet air filtration system, and analyzed the reason why inlet air fitration system cannot adapt to bad weather. Meanwhile, some optimized transformation plans are proposed in this paper, such as arranging the coarse filter G3 in the antifreeze warehouse and adding medium efficiency filter M5 etc. Furthermore, the net benefit in the first year after the optimized transformation is calculated. These optimized transformation plans could effectively decrease the rising velocity of air inlet system′s total pressure differences, reduce the workload and costs of maintenancing air inlet system, extent the lifespan of fine cartridge, enhance the adaptability against bad weather of unit, improve the security and stability of unit operation and increase the economic benefit of unit, which is worth of popularization and application in the optimized transformation of similar gas turbine inlet system.

    Analysis on reason of high exhaust gas temperature of power plant boiler and control measures
    WU Shihua
    2015, 37(7):  65-67. 
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    Abstract:In a power plant, the exhaust gas teperature was higher than designed value by 40℃. Aiming at this problem, the practical coal quality, the air leakage, the combustion situation and the cleanliness of the heating surface were analyzed. The control measures for reducing the exhaust gas temperature were proposed, and the efficiency and economy of the boiler were improved effectively.

    Application of surface acoustic wave temperature measurement technology in wind farm
    GAO Min, GAO Jinming
    2015, 37(7):  68-70. 
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    Abstract:In order to avoid the fire accident in switch contacts of highvoltage electrical equipments during longterm operation, a temperature measurement technology based on surface acoustic wave was proposed. The differences between the temperature measurement technology and the traditional temperature measurement technology were analyzed. The temperature measurement theory using surface acoustic wave was introduced, and a complete passive wireless temperature measurement system was developed. The system is used in the converter cabinet of a wind farm to measure inside cabnet temperature and operates well, and the temperature of the measurement points inside the cabinet can be measured real time and accurately.

    Application of informatization in the third generation nuclear power project
    QIN Siqi
    2015, 37(7):  71-72. 
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    Abstract:This paper summarized the problems appeared and introduced the application of informatization in the construction process of the third generation nuclear power project. In addition, this paper analyzed the problems existed in the currently used project management system and proposed some corresponding improvement measures. At last, the author emphasized the importance of informatization management in nuclear power project.

    Analysis on operation of air conditioning water system of a distributed energy project
    ZHANG Jing
    2015, 37(7):  73-75. 
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    Abstract:The engineering situation and the equipment parameters of a distributed energy project were introduced. The main problems occurred in operation and debugging were expounded. The reasons of the problems were analyzed, and relevant suggestions were proposed, which can be used as reference for treating similar problems.