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RSS2018 Vol. 5, No. 4
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2018, 5(4): 1-11.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.001
Abstract:
[Introduction] Bucket foundation is a promising and environmental friendly foundation for offshore wind turbines. Effectively penetrating this foundation to a design depth with satisfied levelness and avoiding the side soil plug heave or the buckling deformation of bucket skirt and compartment plates during the suction installation are chanlleging problems for the development of bucket foundations. [Method] By summarizing the application of the suction bucket foundation at wind power section in the world, the related mechanisms and methods involved in the two critical issues of penetrating and leveling during the suction construction process were analyzed. [Result] The results show that the accurate estimation for the penetration resistance, the critical suction and the possible structural deformation in layered soils can effectively facilitate the systematic analysis of the instability mechanism of the bucket foundation, the multi-bucket founfation and the compartment-bucket foundation in terms of the installtion risk reduction. [Conclusion] The summary analysis of application of suction bucket foundation for offshore wind power can provide some reference for the foundation penetrating and leveling construction scheme for the actual project.
2018, 5(4): 12-20.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.002
Abstract:
[Introduction] As a new type of clean and renewable energy, wind power attracts widely attention. With the development of wind power from land to sea, offshore floating wind power has developed rapidly. [Method] In this paper, the commercial software ANSYS-AQWA was used to numerically analyze the dynamic response of the OC4 DeepCwind semi-submersible floating wind turbine under typical sea condition of the South China Sea. The equivalent load method was used to caluclate the aerodynamic loads, and potential flow theory was used to calculate the hydrodynamic loads on the platform and the mooring force on the mooring lines. [Results] The results shows the surge and motion response will increase significantly when one mooring line is lost. This may cause the loss control of the platform. When two mooring lines are lost, the motion response will increase appropriately during a certain time. Therefore, it is recommended to use redundant mooring system, i. g. several mooring lines in one group, to have enough time to replace the damaged mooring line. [Conclusion] This work provides a certain reference to the development of offshore wind power in deep water. Further research is needed to study the mechanism of flooded columns damaged and their numerical modeling methods.
2018, 5(4): 21-28.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.003
Abstract:
[Introduction] This paper aims to clarify the concepts and thinking of smart grid. Smart grid is the core platform of the new energy system. It is important for the adjustment of energy structure to develop smart grid . [Method] This paper used the literature review method to sort out the concepts of microgrid, ubiquitous energy network and energy internet and its relationship with smart grid. Combined with China's energy development status and strategic needs, this paper discussed the construction ideas and key points of China's smart grid. [Result] Smart grid is the deep integration of traditional power system and modern information technology, and energy Internet is the deep integration of smart grid and Internet thinking mode and technology. Smart grid is the basic platform of energy Internet. Microgrid, ubiquitous energy grid, smart grid and energy internet all aim to achieve cleaner, efficient and flexible energy use. [Conclusion] Our data suggests that intelligent control on the high voltage side and intelligent built on distribution network should be emphasized and we should encourage the development of ubiquitous energy Internet which focus on the multiple energy sources complement.
2018, 5(4): 29-36.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.004
Abstract:
[Introduction] Domestic electric power system reform is to promote, Yunnan province has release the biggest share of the electricity plan, and take the lead in establishing the day-ahead market. But in the process of building the energy market, the lack of long-term reserve units′ compensation is the problem. [Method] In this paper, the necessity of long-term reserve units compensation and long-term reserve compensation mechanism of typical foreign countries was studied. [Results] Proved that Yunnan needs to establish a reasonable mechanism to compensate for long-term reserve service, at the same time, in combination with the practical situation of power market progress of Yunnan province and put forward recently, mid, and long-term compensation mechanism for long-term reserve service. [Conclusion] This paper have certain reference significance to improve the energy market establishment of auxiliary service market and capacity market in Yunnan and other province.
2018, 5(4): 37-43.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.005
Abstract:
[Introduction] Energy resource in Guangdong is scanty. Energy self-sufficiency ratio is low. And cost of energy is very high. With the increase of economic development and change of industrial structure, energy and source development will face new situation and challenge. The purpose of this article is to strengthen energy supply support capability, reduce energy cost, increase the rate of non-fossil source and optimize source structure. [Method] This paper analyzed the present position of energy development, and forecasted the need of energy and electric power in the future with the scientific and reasonable methods. The method of calculation of energy and power balance was applied. We confirmed the lack of energy and power. Also this paper focused on the way and position of energy and source development strategy with the characters of different energy and source varieties. [Result] The result shows that in long-term period Guangdong energy development should ensure supplies and adjust structure, and in short-term period it should control total and promote clean development. Four source modes in 2030 are proposed, which are low-carbon mode, ecnomic mode, high flexible mode and comprehensive mode. All modes could satisfy the lack of energy and power. And fuel supply capability, environmental protection space and site resource could support the need of source development. By comparison this paper recommends the comprehensive mode. [Conclusion] The research is the reference for Guangdong government.
2018, 5(4): 44-49.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.006
Abstract:
[Introduction] Energy alternatives is an effective measure to promote new energy consumption, improve energy efficiency, and increase the proportion of electricity in terminal energy consumption, it is crucial that rationally select technology of energy alternatives and implement it. [Method] This paper proposed an evaluation system based on regional applicability, economy and popularization difficulty, and the improved analytic hierarchy process(IAHP)was applied to determine the weight coefficient of each index. [Results] Finally, the model is verified by researching object in a southern region. The results show that the model analysis results are consistent with the actual situation, indicating the correctness and rationality of the model. Secondly, the model excludes human intervention factors and provides a scientific methodology, which can actually guide the regional electric energy replacement development. [Conclusion] At the same time, this paper put forward measures to promote the development of energy alternatives, combining the precedence order conclusion and its technology.
2018, 5(4): 50-54.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.007
Abstract:
[Introduction] The white fog is often appeared and causes "visual pollution" if the exhaust gas after wet desulphurization is not controlled. [Method] The white fog phenomenon from the exhaust gas after wet desulphurization was studied theoretically, and the thermal process of the white fog was analyzed with the help of the flue gas thermal characteristic curve equation and "temperature-humidity" chart, so a new scheme of the white fog treatment for cooling, dehumidification and heating was presented. Combined with a typical 1 000 MW ultra-supercritical coal-fired unit, the energy-saving effects of the new scheme were calculated. [Results] The results show that: based on certain boundary conditions of the project and design principles, the saturated gas heating power of the new scheme is decreased by 10.511 6 MW, in two cases that the flue gas waste heat is used to heating condensate water or is not used to heating condensate water, the unit efficiency is increased by 0.231% and 0.164% than the general scheme respectively. [Conclusion] A new scheme of the white fog treatment can achieve the same effect of the white fog treatment and that has better energy-saving effects.
2018, 5(4): 55-59.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.008
Abstract:
[Introduction] The paper aims to solve the problems existing in the operation of the airheaters at the inlet or outlet of the primary fan and the blower in many thermal power plants, such as the small air temperature at the outlet of the heater, the vibration of the pipeline, and the poor drainage, the solutions are put forward. [Method] In this investigation, we analysed several air heaters and their relevant steam /water system and arrangement of the design and the actual operation situation. [Results] In the technical specification, it requires the area of air heater satisfied at the extreme low temperature to meet the cold end temperature requirements of air preheater. In the construction design stage, the steam water system of the heater need optimize so as to meet the requirement of energy saving; the air heater makes high arrangement, and let it drain by gravity way to hydrophobic discharge point. During the commissioning phase, for hydrophobic piping layout with U type, in the early start and lack of pressure it sets hydrophobic discharge at low point . In the operation and maintenance stage, it is necessary to make full use of the control system to combine the drainage of the heater with the air temperature control to ensure the safe, stable and economic operation of the system. [Conclusion] The analysis and research in this paper are based on the theory and other engineering optimization cases. It has practical application value and can be used as a reference for other projects.
2018, 5(4): 60-65.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.009
Abstract:
[Introduction] The early buckling theory of cylindrical shells under axial compression has a great deviation from the experimental results, there are many factors that lead to differences, the initial geometrical defect is the main factor that produces the difference. [Method] In this paper, a special axial compression buckling test platform was used to scan the three-dimensional actual topography of the shell by using a laser displacement sensor, and the axial compression buckling test was carried out by the hydraulic device. [Results] The results show that the critical load of axial buckling of cylindrical shells is reduced by opening holes, and the buckling load of the cylindrical shell is improved by inserting a circular tube in the opening hole. Based on the measured data of shell topography, a finite element model is established, and the nonlinear buckling finite element analysis of cylindrical shells, cylindrical shells with openings and reinforcement is carried out by Abaqus. [Conclusion] The law of simulation is consistent with the experiment, the axial load of the shell is increased firstly and then decreased, the critical load of the axial compressive buckling of the cylindrical shell with opening is the least, the critical load of the cylindrical shell with the reinforcement is the second larger, the buckling critical load of the cylindrical shell without openings is the largest. The critical load simulation values of different shells are compared with the experimental values, in which the minimum relative error is only 13.8%. This method can be used to predict the critical buckling load of the shell, and it is of reference value to the buckling design of the shell.
2018, 5(4): 66-72.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.010
Abstract:
[Introduction] Sealing of reactor pressure vessel is one of the key factors in the safe operation of nuclear power plants, and therefore it has significant importance in engineering to conduct the in-depth study of its contacting systems. Based on the application characteristics of finite element analysis, we have developed independently a software ATLAS, where a lot of innovation optimizations have been done in terms of pre-sorted file caching and 3D rendering technologies that allows CAE engineers working in highly interactive and visual environments. [Method] In this paper we used ATLAS to create a pressure vessel model, and then simulated numerically the contacting and the sealing of pressure vessel, and finally obtained the mechanical characteristics and stress distribution, and evaluated the strength and fatigue analysis of its critical section. [Results] The results show that ATLAS can accurately import and mesh models, apply a variety of conditions, quickly complete finite element analy ele sis of contact problems. The accuracy of the results can be guaranteed, according to the methods, the designed flange meets the requirements of structural strength and durability. [Conclusion] As a rapid finite element analysis system for large-scale structures, ATLAS provides tools for structural sealing analysis and strength checking for reactor pressure vessel and it has good application prospects.
2018, 5(4): 73-77.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.011
Abstract:
[Introduction] Safety, reliability and economy of island power supply is an important task in power system planning and design. [Method] According to an example of power supply planning on the island in the south of China, a comprehensive comparison about feasibility, reliability, investment and price between local gas power development and flexible HVDC connection was introduced based on setting up and solving the integer programming model of the configuration of the gas turbine group. [Results] The results show that: in order to satisfy the island power demand and take into account the uncertainty of long-term load growth, it is recommended to adopt the hybrid power supply scheme of local gas power and interconnection under feasible technical conditions. [Conclusion] These methods and results provide a reference for the power system planning and design of other similar islands.
2018, 5(4): 78-85.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.012
Abstract:
[Introduction] The paper aims to improve the reliability of the multi-terminal circular flexible DC distribution network, the characteristics of the fault in the different grounding mode of the AC side and its influence on the protection configuration are studied. The fault characteristics of multi-terminal circular flexible DC distribution network under different AC grounding modes were studied, and the impact on protection configuration had been given. [Method] First of all, the equivalent AC/DC fault path of two-level and modular multi-level converter equipment was determined, and the influence of different grounding modes were analyzed from the aspects of fault overvoltage, overcurrent level and fault recovery. Then from the aspect of protection principle configuration, setting value setting, export mode and cooperation principle, the typical protection configuration scheme of multi-terminal circular flexible DC distribution network was given. Finally, the electromagnetic transient model of the three-terminal flexible DC distribution network was established under the PSCAD /EMTDC simulation software. [Result] The simulation results show that when the AC side adopts a high resistance grounding mode, a reasonable protection configuration can improve the stability of the system when the AC asymmetrical fault occurs, and achieve zero interruption time fault ride through when the DC asymmetrical fault occurs. [Conclusion] The research provides some reference for the design of grounding mode and the research on protection configuration of flexible multi-terminal DC distribution network.
2018, 5(4): 86-91.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.013
Abstract:
[Introduction] In order to saving the transmission line corridor, the ±800 kV polar wires and electrode wires have been erected on the same tower in the highly urbanized areas such as Guangzhou and Shenzhen. There is an potential risk of bipolar blocking to HVDC system due to configuration of the same tower for both ±800 kV polar wires and electrode wires, but there is little research on it in China. [Method] In this paper, the process of bipolar blocking caused by the lightning stroke in hybrid transmission lines was analyzed. Taking a project as an example, this paper calculated the lightning flashover rate of hybrid transmission line which erecting polar wires and electrode wires on the same tower by using the ATP-EMTP electromagnetic transient simulation program and the electrical geometric model. Based on this, several measures to reduce the risk of bipolar blocking were discussed. [Results] The results show that the lightning flashover rate of hybrid transmission line is lower than the independent erecting DC lines. Measures of adding line lightning arrester in the electrode wires, replacing the electrode wires of tower cross-arm for the composite cross-arm, adding the electrode wires insulation level can effectively reduce the risk of bipolar blocking. By comparison of technology and economy, this paper recommended the case project is adopted to improve the electrode wires insulation level as the anti-accident measures. It is suggested that case project should be equipped with 15 pieces of 170 mm structure height insulator. [Conclusion] This results provide certain technical support for the design of HVDC lines in congested areas.
2018, 5(4): 92-97.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.014
Abstract:
[Introduction] The paper aims to discuss the factors which influence the accuracy of monopile foundation evaluation. [Method] Firstly, beam model and local finite element model were bulit to simulate the monopile foundation structure response. Secondly, the fatigue damage coming from wave was evaluated by spectrum fatigue method. Finally, the factor of the transfer function, wave theory and the penetration which influencing the fatigue life of the monopile foundation was discussed in this paper. [Result] According to the analysis results, it can be get the conclusion that the transfer function and the type of penetration have significant effect on the fatigue strength of offshore monopile foundation. [Conclusion] We demonstrate the feasibility of the computing method and analysis results, this work provides some guidance for practical application.
2018, 5(4): 98-104.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.015
Abstract:
[Introduction] In voltage sourced converter based ultra-high voltage direct current (VSC-UHVDC) converter station, the roof span of valve hall far exceeds the previous project, and the traditional trapezoidal steel truss structure is no longer applicable. [Method] In the absence of experience for reference, the structural design of long span roof was studied based on the characteristics of the VSC-UHVDC valve hall, and a reasonable structural type was confirmed. Starting from the number of grid layers, the height of grid, the form of joints and the form of grid, the optimal design of the long span space grid roof was carried out. [Results] The results show that the optimized three-layers diagonal square pyramid grids roof has good structural performance and economic benefits, and is an excellent structural form the long span roof of VSC-UHVDC valve hall. [Conclusion] The optimized structure of the grid roof can be used for reference by similar projects.
2018, 5(4): 105-110.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.016
Abstract:
[Introduction] For the purpose of unifying and standardising construction process of substation, the assembled building is popularized and its standard design principles are made by the State Grid Corporation of China. However, it may result in unnecessary waste if the designers always simply apply the standard design principles and atlas. Combining the development of construction materials and practical application, the refined design is necessary and essential. [Method] On the premise of meeting the requirements of structure, function, energy conservation, noise reduction and fire prevention of the building, and basing on the performance of building materials, refined design of the assembled building wall of substation was presented and the concrete design parameters such as wall material and dimensions achieving energy conservation and material saving were clarified. [Results] After several practical tests in the field, it shows that this technique is effective on saving construction materials, reducing size of construction site and energy conservation. [Conclusion] The feasibility and practicability of this technique is demonstrated, which can provide reference and guidance for the engineers and managers in the similar projects.
2018, 5(4): 111-116.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.017
Abstract:
[Introduction] In China, the power consumption of power grid enterprises data centers is increasing. To calculate the whole energy effectiveness condition of the data centers, this paper proposes a feasible power grid enterprise data center energy effectiveness measurement standard and calculation method. [Method] By studying the data center energy effectiveness evaluation methods both in China and abroad, in view of the features which power grid enterprises data centers may share some of the infrastructure with their office buildings, we proposed three kinds of optimization methods, including accurate calculation of IT load, optimized estimation of power consumption of power distribution unit in the cabinet, optimized estimation of power consumption of the cooling water system, and the optimized energy effectiveness measurement and calculation method. [Results] The results show that: by using this method, energy consumption in non-data center regions can be separated in calculation, which is more accurate than the conventional calculation method, closer to the international general data center power effectiveness definition, and can truly reflect the power effectiveness level of power grid enterprise data center. [Conclusion] The proposed method is simple and effective, which can provide the basis for comparing energy effectiveness with different data centers and energy saving level assessment.
2018, 5(4): 117-123.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.018
Abstract:
[Introduction] In order to realize standardized application and engineering popularization of prefabricated optical cable in standard distribution substation, it is necessary to study the project application scheme and engineering implementation problems of prefabricated optical cable. [Method] Based on the engineering application and demand of prefabricated optical cable in standard distribution substation, this paper compared the engineering application schemes with the structural type, optical cable type and prefabrication mode of prefabricated optical cable, it also studied some common problems and its solutions such as laying, attenuation control and residual length control. [Results] This paper unifies the structural type, optical cable type and prefabrication mode of prefabricated optical cable, solves the problems of cable laying, attenuation control and redundancy control length. It can shorten the construction period and save the investment, improve the applicability and economy of prefabricated optical cable in standard distribution substation. [Conclusion] Combining with the results of this paper, the standard distribution substation can choose the applicable project application scheme and project implementation scheme according the project scale and equipment layout and realize the modular installation and wiring of the whole station optical cable.
2018, 5(4): 124-129.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.019
Abstract:
[Introduction] With the expansion of offshore wind energy development center from Jiangsu to Guangdong, Fujian and other provinces, the rock-socketed problem of offshore wind turbine foundation has gradually become the core issue in offshore wind energy development. The cost of wind turbine foundation in rock-socketed area severely restricts the cost of offshore wind farm, so the selection of wind turbine foundation in rock-socketed area is particularly critical. [Method] This paper first discussed the rock-socketed construction technology of several wind turbine foundations, then discussed the selection basis and principles of offshore wind turbine foundations in rock-socketed areas, and finally prospected the development of offshore wind power rock-socketed problems. [Results] The study shows that the selection principle of wind turbine foundation scheme in rock-socketed area of offshore wind farm should be comprehensively compared from three aspects: structural safety, construction feasibility and economy. Among the three factors mentioned above, the requirements of structural safety should be satisfied first, the requirements of construction feasibility should be satisfied on this basis, and the influence of economy should be considered at last. [Conclusion] The research results can provide reference for offshore wind turbine foundation design in rock socketed area.
2018, 5(4): 130-134.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.020
Abstract:
[Introduction] It is of great practical significance to carry out the research on the operation and maintenance technology of power communication cable. [Method] Based on the typical research of Zhoushan archipelago, according to the characteristics of island power grid, this paper discussed the operation and maintenance of coastal communication cable, introduced the operation status of various common optical cables, and analyzed the problems existing in the operational and dimensional process. [Results] The results show that the independent optical cable is preferred in island power communication project, and the optoelectronic composite cable is only used as line monitoring. [Conclusion] It puts forward some suggestions and countermeasures, provides some beneficial enlightenment and reference for the efficient production management of cross-sea power grid.
2018, 5(4): 135-140.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.021
Abstract:
[Introduction] Under the current practice of benchmarking on-grid electricity price for newly-built new nuclear power units, in order to effectively address the problems of excessively high construction cost of domestic nuclear power projects and insufficient attention to the economy of nuclear power, combining the reality of general uncompetitive domestic nuclear power on-grid electricity price in the electricity market, in order to reduce the construction cost of the Zhangzhou nuclear power project and further increase the competitiveness of the on-grid electricity price for Zhangzhou nuclear power project. [Methods] The comprehensive analysis of the construction cost for domestic nuclear power projects was made, the construction cost lean management in the preliminary stage of Zhangzhou nuclear power project was put forward. Combining the actual situation of Zhangzhou nuclear power project, the analysis of specific methods and measures for implementing cost lean management was made, in the stages of the preliminary preparation, investment decision-making, management mode selection and so on. Firstly, the land and sea acquisition mode in the preliminary stage and the innovative practice of "two-phase" procurement mode. Secondly, the optimization of current nuclear power project construction management mode was adopted. Thirdly, the development of 1 000 MW-level nuclear power technology and economy model used for benchmarking and defining the principles and standards for cost control in the preliminary stage were discussed.Fourthly, the research and implementation of "integration of nuclear power and pumped-water storage" to ensure the competitiveness of on-grid price of nuclear power were discussed. Fifthly, the establishment of effective cost control mechanism for nuclear power projects and staff cost control culture were discussed. [Results] The above lean management methods and measures can directly save a large amount of investment for the Zhangzhou nuclear power project in the preliminary stage, shorten the construction period of the Zhangzhou nuclear power project, reduce the construction cost of the nuclear power project, and further increase the competiveness of the on-grid electricity price for the Zhangzhou nuclear power project. [Conclusion] The construction cost lean management in preliminary stage of Zhangzhou Nuclear Power Project is very effective, not only can improve subsequent competitiveness of on-grid electricity for Zhangzhou nuclear power project, but also reduce nuclear power construction cost and improve the economy of nuclear power .And the Zhangzhou nuclear power mode and experience can provide reference for the nuclear power industry.
2018, 5(4): 141-146.
doi: 10.16516/j.gedi.issn2095-8676.2018.04.022
Abstract:
[Introduction] With the slowdown of power demand and the reduction of traditional thermal power projects in China, the business environment of electric power design enterprises is deteriorating. But the PPP mode brings a new chance for electric power design enterprises to develop non-electric business and realize the transformation. [Method] In order to identify the development prospects of electric power design enterprises to participate in the PPP projects, the paper attempted to identify internal factors such as strengths and weaknesses, analysed opportunities and threats using the SWOT method. [Results] The results we obtained demonstrate that electric power design enterprises have unique advantages in participating in PPP projects, and should make full preparations from the six dimensions of system, ability, market, resources, risk and talent based on national policies, macroeconomic environment and their own situation. [Conclusion] This work provides some reasonable countermeasures accordingly for electric power design enterprises to participate in the PPP projects, and suggests that only when electric power design enterprises make up their own deficiencies they can make full use of their advantages and reduce the investment risks of PPP projects, so as to achieve sustainable development.
