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    Research & Analysis
  • Research & Analysis
    Stage Test and Simulation on Advanced and Efficient Impulse Blade Profile of Steam Turbine
    Ping Yan, Tao Zhijian, Huang Yuandong, Bai Kunlun
    2024, 38(4): 199-204. https://doi.org/10.19806/j.cnki.fdsb.2024.04.001
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For two types of advanced and efficient impulse blade profiles (LH, LL blade profiles) in steam turbines, analyses were conducted on the multi-stage air-medium stage test and numerical simulation, so as to research the overall performance difference between the two types of impulse blade profiles in real stage environment. Results show that, the simulation values of air flow rate with two types of impulse blade profiles basically coincide with the test values, while the LH blade profile has a higher through-flow efficiency. In addition,the simulation values of the optimal speed ratios of two types of impulse blade profiles are both higher than the test values. Finally, with the increase of the speed ratio at the root, the reaction degree at the root of the through-flow stage gradually increases, and the simulation value of reaction degree is higher than the test value. The design concept of LH blade profile is more reasonable than that of LL blade profile, and the effect of performance improvement can satisfy the expectation. Research results may provide an important reference for the engineering application of LH blade profile.
  • Research & Analysis
    Extraction of Core High Temperature Region of Boiler Flame Image Based on Mask R-CNN
    Zhang Shenghua, Long Jiajian, Lu Jidong
    2024, 38(4): 205-210. https://doi.org/10.19806/j.cnki.fdsb.2024.04.002
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    In order to improve the accuracy and stability of feature extraction of the core high temperature region of boiler flame, a method of extracting the contour of flame core high temperature region based on Mask R-CNN (mask region-based convolutional neural network) was proposed in combination with the flame characteristics of tangential-fired boiler. About 10 000 frames of historical operational flame images from the industrial flame monitoring system of a 330 MW coal-fired boiler were used for modelling, and the flame images of uploading conditions were processed and verified online. Results show that, the accuracy of core high temperature region detection based on Mask R-CNN model reaches 92.35%, which has higher stability than traditional threshold segmentation method and edge detection method. The Mask R-CNN model can better adapt to the characteristics of the fluctuation and rapid change of the pulsating flame when the load changes, and the contour edge is less affected by other regions, which is conducive to the extraction and calculation of the flame geometry and distribution characteristics for the contour of the flame core high temperature region.
  • Research & Analysis
    Optimization on Steam Turbine-driven Feedwater System and Steam Distribution System for Thermal Power Units with Deep Peak Regulation
    Cheng Liang, Lin Lin, Wen Bin, Zhou Gang, Wang Lei, Li Yaofeng
    2024, 38(4): 211-216. https://doi.org/10.19806/j.cnki.fdsb.2024.04.003
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    For a thermal power unit, analyses were conducted on the main influence factors of each system in steam turbine on the economy under deep peak regulation condition, and researches were emphatically carried out for the operation economy of steam turbine-driven feedwater system and steam distribution system. The differences of unit operation economies with different steam sources for steam turbine-driven feedwater pump were calculated and analyzed based on EBSILON modelling platform, the operation economy indexes of the unit under different main steam pressure conditions were quantitatively calculated, and the influence of the adjustment of the butterfly valve in interconnecting pipe on the economy was analyzed. Results show that, the economy of the fourth stage steam as the steam source is better than that of cold reheated steam, and the steam turbine heat rate would be increased by 123.7146.5 kJ/(kW·h) when adjusting the steam admission of steam turbine-driven feedwater pump with the butterfly valve in interconnecting pipe. The unit operation economy can be improved by the appropriate decrease of main steam pressure under deep peak regulation condition.
  • Research & Analysis
    Economic Optimization Model and Application of Off-line Washing Period for Heavy-duty Gas Turbine
    Wu Zhanyuan, Zhang Zhaoyu, Ji Jingjin, Sun Bo
    2024, 38(4): 217-222. https://doi.org/10.19806/j.cnki.fdsb.2024.04.004
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    Off-line washing of compressor can eliminate the scale deterioration and improve the unit performance, and the off-line washing period has a significant impact on power plant operation income. An economic analysis method and model of gas turbine off-line washing period was presented. The average washing cost of period was taken as the optimization index, and the optimal off-line washing period was proposed. Based on the model, the optimal off-line washing period of the unit in Hainan Province was calculated, and the sensitivity of each boundary condition was analyzed. Results show that, the optimal off-line washing period for the unit is approximately 740 h, which can increase the profit by 84 000-180 000 yuan per year compared with the actual operation of 550 and 1 200 h. Factors such as fuel price, on-grid price, and compressor scaling rate all have significant impacts on the optimal washing period. The model has been applied in power plant, and the research results can provide a reference for the off-line washing period decision of other gas turbine power plant compressor.
  • Research & Analysis
    Numerical Simulation Analysis of Influening Factors on Plume Diffusion in a Coal-fired Power Plant
    Li Yazhou, Lei Chengyong, Xiong Zhenqin, Zhang Guokun
    2024, 38(4): 223-228. https://doi.org/10.19806/j.cnki.fdsb.2024.04.005
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    For a coal-fired power plant chimney with a height of 210 m and an outlet diameter of 7 m, the diffusion process of water vapor in the environment was calculated based on Ansys Fluent software to analyze the impact of different factors on the diffusion of plume. Results show that, the increase of ambient temperature and the decrease of flue gas temperature and humidity can significantly reduce the volume of plume. Wind speed and flue gas velocity have a minor impact on the volume of plume, while affecting the vertical and horizontal distribution of the plume. The increase of wind speed causes water vapor to diffuse to a greater distance at lower altitudes with higher concentration. The increase of flue gas velocity promotes the droplet diffusion in the vertical direction.
    • Auxiliary Equipment Technology
  • Auxiliary Equipment Technology
    Application of Boiler Water Circulating Pump in Start-up System of Ultra-supercritical Boiler
    Xiong Kaibin, Chen Zhenyu, Ran Shenming, Li Xusheng, Zhou Wei
    2024, 38(4): 229-234. https://doi.org/10.19806/j.cnki.fdsb.2024.04.006
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Boiler water circulating pump (BCP), as the core equipment of the start-up system of ultra-supercritical boiler, plays an obvious role in the unit start-stop efficiency, regulation characteristics and low-load safety, and can better adapt to the needs of deep peak regulation of power grid. Through the comparison of domestic and imported BCP in terms of price, delivery and quality guarantee period, domestic BCP has obvious advantages. With the increase of domestic demand for peak regulation of thermal generating units and the promotion of power generation equipment localization, the market demand for domestic BCP has become increasingly prominent. At present, there is still a gap between domestic BCP and imported products in application performance, but with the expansion of market demand, it has a certain development prospect.
    • Design & Manufacture
  • Design & Manufacture
    Comparison on Design Methods for Large Plate Girder Segmentation of Boiler Steel Structure Between Chinese and American Standards
    Zhao Bin
    2024, 38(4): 235-242. https://doi.org/10.19806/j.cnki.fdsb.2024.04.007
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to reduce the transportation costs and meet the requirements of hoisting assembly and transportation, the large plate girders of 660 MW and above boilers generally need to be designed in blocks manner in height and length directions to form a segmented superposed beam, while high-strength bolts are applied to the connection in height and length directions. Taking a specific engineering of a 660 MW boiler in Guizhou Province as the research example, based on GB 50017—2017 Standard for Design of Steel Structures in China and ANSI/AISC 360-16 Specification for Structural Steel Buildings (LRFD method) in America, design methods for the flange splicing, web splicing, and laminated surface splicing connections of the segmented superposed beam were presented. For high-strength bolts used in segmented connections, the single bolt bearing capacity calculated by American standard is relatively greater, and there is less demand for the number of bolts, while Chinese standard tends to be more safe. For the plates used for segmented connections, the stress coefficients calculated by American standard are lower than those calculated by Chinese standard. For the design of large plate girder segmentation, the safety levels of above two standards are basically the same, while the Chinese standard is slightly more conservative. Research results provide a reference for the connection design of segmented superposed beam of boiler steel structures.
    • Automatic Control
  • Automatic Control
    A Comprehensive Control Method for Energy Storage Battery Under Adaptive Control Participating in Primary Frequency Modulation of Thermal Power Generating Unit
    Luo Xiaojun, Li Ruiping, Wang Chi, Lu Wanglin, Bao Jiaqi, Zhao Huirong
    2024, 38(4): 243-249,268. https://doi.org/10.19806/j.cnki.fdsb.2024.04.008
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    For the defect of insufficient control ability of energy storage battery when participating in primary frequency modulation of thermal power generating unit, an adaptive comprehensive control method was proposed to optimize energy storage battery output based on primary frequency modulation characteristics and the state of charge (SOC) of energy storage battery. By analyzing the frequency modulation characteristics of the power grid, the virtual inertia control was improved to get the virtual negative inertia control. In the early stage of frequency modulation, the energy storage battery output was mainly based on droop control and supplemented by inertial control. In the frequency recovery period, it was mainly based on the inertial control and supplemented by droop control. In order to optimize the power output of energy storage battery, an adjustment strategy of adaptive output coefficient was set based on logistic function to maintain a good state of SOC. Taking a typical single region power grid as an example, a MATLAB/Simulink simulation model was built to verify the proposed adaptive comprehensive control method, Results show that, the control strategy can reduce the frequency deviation quickly and effectively, and make the power system quickly recover to steady state value of primary frequency modulation frequency.
  • Automatic Control
    Experiment and Analysis on Primary Frequency Control Capability of New Energy Power Generation in Receiving-end Power Grid
    Zhou Shuai, Zhang Tianhai, Zhang Liudong, Yu Guoqiang, Bu Jing
    2024, 38(4): 250-255. https://doi.org/10.19806/j.cnki.fdsb.2024.04.009
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Through on-site simulation frequency disturbance tests and real frequency disturbance tests of the power grid, the primary frequency control performance of new energy stations in East China receiving-end power grid was tested. Results showed that the new energy stations can ensure sufficient reserve power through active power reserve function, so as to meet the requirements of primary frequency control of the power grid, while the frequency control characteristics of photovoltaic power plants are better than those of wind farms in terms of rapid response, stability and power contribution. Research results can provide a reference for setting differentiated parameters between wind farms and photovoltaic power plants in East China power grid.
  • Automatic Control
    Research on Stable Steam Supply of a Supercritical Double-extraction Back-pressure Heating Unit Under the Condition of Steam Turbine Tripping Without Boiler Shutdown
    Kang Ruiting, Tang Haoyuan, Sun Yongbin, Wang Li, Jie Qiliang, Liu Tianyu
    2024, 38(4): 256-263. https://doi.org/10.19806/j.cnki.fdsb.2024.04.010
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    The control mode of the high-pressure bypass control valve and the automatic switching mode of its adjustment object were studied under the condition of steam turbine tripping without boiler shutdown of a supercritical double-extraction back-pressure heating unit. Multistage pulse control technology was used to realize the full stroke control of the high-pressure bypass control valve. Results show that,the steam turbine trip signal is used to automatically trigger the adjusting object switcher of high-pressure bypass control valve, which can realize the non-disturbance switching of the main steam and the reheat steam as the steam supply source. At the same time, the steam turbine trip signal is used to trigger the rapid load reduction of the boiler, which can realize the overall safe and stable operation of the unit. This research realizes the function of stable steam supply of the unit under the condition of steam turbine tripping and boiler operating.
    • Fault Diagnosis
  • Fault Diagnosis
    Ultrasonic Phased Array Inspection Technology for Stress Corrosion Cracks in Impeller Root Grooves of Nuclear Steam Turbines
    Wang Jinhua, Li Siqi, Wu Qitai, Yang Min, He Zhiqing
    2024, 38(4): 264-268. https://doi.org/10.19806/j.cnki.fdsb.2024.04.011
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The impeller root groove of nuclear steam turbine is a stress corrosion susceptible part, which should be subjected to nondestructive testing periodically. However, in actual testing, the impeller root groove is tested in an environment with complex structure and restricted space, and the testing results are difficult to reflect the real situation of the root groove surface. Therefore, an ultrasonic phased array inspection scheme was proposed for the inspection of the impeller root groove of nuclear steam turbine. The impeller-root body specimen with artificial defects was processed according to 1∶1, and the test equipment and sweeping method were determined by CIVA simulation platform. Meanwhile, the defects were detected for four times on the specimen. Experimental results show that the scheme can identify all artificial defects and realize the localization and quantification of defects, while which has a high detection accuracy and feasibility. The safe operation of nuclear steam turbine can be effectively ensured with this technology.