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Ren Y.,Chongqing Three Gorges University | Ren Y.,North University of China | Ren Y.,Beijing Institute of Water | Wan Y.,Wuling Power Corporation LTD. | And 2 more authors.
Shanghai Ligong Daxue Xuebao/Journal of University of Shanghai for Science and Technology | Year: 2016

To solve the problem of multiple noises existing in wind farms which affect the partial discharge (PD) online monitoring results of oil immersed transformers, a partial discharge online monitoring and analysis method for the transformers in wind farms based on the ultra high frequency (UHF) technology was put forward and the design of the UHF PD sensor and frequency reduction circuit of its supporting hardware was made. The UHF partial discharge monitoring and analysis model for the transformers, including their hardware framework and software construction scheme was built. The method was verified by the measured signals in a certain wind farm, which proves that the method proposed can effectively avoid electromagnetic interference, obtain reliable real partial discharge pulse, and realize the fault diagnosis for transformers in wind farms. © 2016, Editorial Board of Journal of USST. All right reserved.

Zhang G.-J.,Changsha University of Science and Technology | Zeng L.-X.,Changsha University of Science and Technology | Chen A.-Z.,HydroChina Zhongnan Engineering Corporation | Yang S.-L.,Wu Ling Power Corporation | Peng C.-L.,Hongyu Engineering
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

For the impervious construction in soft stratum, there are various technical problems, such as easy collapse of boreholes, vertical lift induced by difficultly pressed grouting, large waste led by easy grouting leakage, and difficult grouting control. The traditional methods of "sleeve valve pipe grouting", "embedded screen pipe tube" and "orifice closed grouting" are difficult to meet the design requirements in deep soft ground. To reduce cost and to improve efficiency, a new construction method, high pulsating pressure grouting from below with stemming slurry materials, is put forward, and one of the key techniques, slurry sealing technique, is described. For the construction requirements, a kind of low-intensity, rapidly solidified and hard plastic-like sealing slurry is developed, and its performance parameters are obtained. It is enough to stem grouting and to consume energy by filling slurry materials between grouting pipe and bore hole pipe wall based on the grouting mechanism. The bottom-up pulling force which provides the basis for choosing pulling machines for construction is calculated. In addition, if you turn the grouting pipe continuously during the process of grouting, the work efficiency can be improved and the grouting pipe can be smoothly promoted to avoid locking accidents even in deep borehole cases without pipe drawing machines. Through the tests on the deep soft stratum in the bay area of Tuokou Hydropower Station, the slurry materials achieve the desired effect. Theoretical study and engineering practice show that it's feasible to adopt slurry sealing technology and to implement high-pressure grouting in soft stratum, and that the construction techniques by means of stemming slurry material can meet requirements.

Ren Y.,Chongqing Three Gorges University | Ren Y.,North China University of Water Conservancy and Electric Power | Bi Y.,Chongqing Three Gorges University | Gong C.,Wuling Power Corporation | Qian D.,North China Electrical Power University
ICIC Express Letters | Year: 2016

With the development of wind energy, its intermittency challenges frequency stabilization of power systems. Power systems also suffers from the nonlinearity of generation rate constraint (GRC). The intermittency and nonlinearity challenge load frequency control (LFC). This paper addresses a control scheme for the LFC problem of a nonlinear power system with wind turbines. To achieve the LFC task of the power system, the control scheme combines sliding mode control and neural networks. From the Lyapunov direct method, update formulas of the neural networks are formulated so that the control system is of asymptotic stability. Simulation results are presented to show the performance and effectiveness of the presented control scheme. © 2016 ICIC International.

Zhang G.,Changsha University of Science and Technology | Yang S.,Wuling Power Corporation | Chen A.,HydroChina Zhongnan Engineering Corporation | Zhang Q.,Wuling Power Corporation
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2012

With the marked difference of the groutability in one borehole of the deep complex rock and soil stratum, grouting materials must change accordingly and grouting methods should enjoy great suitability. The present grouting materials is short of controllability and groutability. In the present grouting method, the density changes gradually in every length of grouting section which makes the grout scattering difficult to control, the grout wasteful to discard and the work efficiency low. Considering the practical needs of the construction technology in the grouting process and the performance optimization of the grouting materials, a controllable stable slurry is made mainly from clay and cement which is developed by taking advantages of the good performance of the clay, very low plastic viscosity and yield strength of sodium silicate slurry, the traits of cement's solidification and strength, and modifier through the laboratory test of large-sample. The performance of this kind of slurry satisfies the general needs of the anti-seepage engineering, besides, the rheological parameter, setting time and concretion parameters can be adjusted on a large scale. As for the complex stratum, the tested controllable grouting materials and corresponding means of providing the materials can be selected according to the differences of the characteristics of grouted rock and soil, which can realize quick preparation of the grouting materials during the process and make the grouting easier, the discard grout few and the cost lower. The completed grouting test in the anti-seepage curtain engineering at river bend plot of Tuokou hydropower station indicated that compared with the traditional grout and grouting method, the injection volume has reduced about 65%, the efficiency of the rigmonth(m/(rig·month)) has increased about 30%; and the grouting quality meets the design requirements. Hence the research result can be widely applied to the project as well as other similar ones.

Tang B.B.,Central South University | Liu B.C.,Central South University | Deng Z.H.,Wuling Power Corporation
Applied Mechanics and Materials | Year: 2013

This paper takes cascade hydropower station project as the research object. It puts forward an economic post project evaluation of hydropower station's analysis framework -- "Static analysis and comprehensive evaluation" based on building the evaluation index set and data envelopment analysis. This paper takes economic post project evaluation of Yuanshui cascade hydropower station as an example to verify the science and effectiveness of the analysis framework and model. The results enrich the theory and model technique of economic post project evaluation of hydropower stations. © (2013) Trans Tech Publications, Switzerland.

Xu H.-N.,University of Sichuan | Pang X.-B.,Wuling Power Co. | Xu J.,University of Sichuan | Liu J.-F.,University of Sichuan
Sichuan Daxue Xuebao (Gongcheng Kexue Ban)/Journal of Sichuan University (Engineering Science Edition) | Year: 2012

Tri-axial creep test was carried out on borehole sampling basis in order to reveal the creep characteristics of purple silty mudstone in the Upper Silurian in the center and west of North Tianshan, and provide the basis for the designing, construction and long-term stability evaluation of the proposed deep and long tunnel. Test was performed on five rock tri-axial creep test machines with the confining pressure of 0, 5, 10, 20 and 30 MPa, respectively. Through the study, the following resulted were achieved. Rock creep characteristics was proved to be describable by the Xiyuan Model and a creep constitutive equation was establish for this kind of mudstone. The creep parameters were gained by calculating them based on creep curves. Long-term rock strength was obtained by superposition theorem and isochronous curve method, and the confining pressure effect was revealed on the long-term strength. The creep parameters increased with the increase of confining pressure, and the difference between long-term rock strength and instant rock strength increased by 25% under uni-axial pressure and 52% under tri-axial pressure of 30 MPa as the confining pressure increased. The long-term shearing strength decreased by 60%(cohesion) and 36% (internal friction angle) compared with the instant shearing strength. These results provided a scientific basis for the engineering construction, and the test and result collation methods were available for other similar construction and research. Meanwhile, physical and mechanical property of silty mudstone was also obtained through routine tests, which helps to apply creep test result to other similar projects.

Tang B.B.,Central South University | Liu B.C.,Central South University | Deng Z.H.,Wuling Power Corporation
Applied Mechanics and Materials | Year: 2013

The environmental post evaluation index system is proposed to evaluate the cascade hydropower project's post environmental impact assessment. We also constructed an evaluation method based on Matter-element and Analytic-hierarchy coupling model (FME-AHP) to apply to the environmental impact assessment of Yuan Shui cascade hydropower stations. It can test the index system and evaluation method is scientific and validity or not. We hope we can provide some experience and reference for the environmental impact assessment of the hydropower exploitation in key river basin both in China and abroad. © (2013) Trans Tech Publications, Switzerland.

Gong C.,China Institute of Water Resources and Hydropower Research | Wan Y.,China Institute of Water Resources and Hydropower Research | Wan Y.,Wuling Power Corporation | Chi H.,China Institute of Water Resources and Hydropower Research | Yang Y.,China Institute of Water Resources and Hydropower Research
Applied Mechanics and Materials | Year: 2011

Partial discharge (PD) pulses recognition, which is directly related to the credibility of PD online measurement results, is the key technology of the high-voltage (HV) equipment PD online monitoring. In this paper, a pulses recognition method during PD online measurement was put forward to extract PD pulses buried in external interferences, the method adopted three key steps to identify PD pulses: (a) Firstly, two pretreatments, including discrete spectrum interferences (DSI) suppression and single pulse boundaries determination, are used to convert several consecutive power cycles on-site monitoring signal to plenty of pulse - time sequences; (b) Then, an optimized adaptive clustering algorithm is adopted to classify all pulses into certain categories (c) Finally, the three-dimensional distribution of each category which indicated the pulses phase distribution with power cycles was calculated, and the PD pulses were identified by the statistics characteristics of their three-dimensional distribution. At present, the PD pulses recognition method has been used in industrial application, and on-site monitoring signal processing results has proved the effectiveness of the method. © (2011) Trans Tech Publications.

Tang B.,Central South University | Liu B.,Central South University | Deng Z.,Wuling Power Corporation
Advances in Intelligent Systems and Computing | Year: 2014

This paper established a new scale matrix and quantitative decision-making model for the characteristic that development of hydropower resources has great impact on the ecological environment of the whole basin based on analytic hierarchy process (AHP) decision theory. The model put forward the quantifying AHP decision method based on variation characteristics of effects of cascade hydropower environmental factor. This paper takes the development plan of Yuanshui hydropower energy as an example to make an evaluation and decision. In consideration of the impact on the ecological environment of the entire basin, we evaluated the development plan. The empirical study shows that the effect of quantization AHP decision model is very good. © Springer-Verlag Berlin Heidelberg 2014.

Liu Z.,Changsha University of Science and Technology | Rao H.,Changsha University of Science and Technology | Huang Z.,Changsha University of Science and Technology | Zhong Y.,Wuling Power Corporation | Li J.,Wuling Power Corporation
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2015

A method of blade opening adjustment for hydraulic turbines based on substitute angle measurement is studied and presented herein to overcome the difficulty in accurate onsite measurement of blade angle and its unfavorable effect on the adjustment. We give a definition of substitute blade angle and methods for its measurement and calculation, and determine the thickness modification of adjusting shims according to a blade opening conversion ratio and the interaction between adjacent blades. This method was applied in situ to a bulb turbine and its blade openings were successfully adjusted. The results show that it improves the uniformity of blade openings and the synchronism of blade angles effectively, so as to better the hydraulic performance of turbines and their efficiency and operation stability. ©, 2015 All right reserved.

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