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RSS2018 Vol. 5, No. 3
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2018, 5(3): 1-7.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.001
Abstract:
[Introduction] With the rapid development of offshore wind power, it is necessary to develop new foundation structure of offshore wind power to meet the design requirements of deep water and soft soil foundation. [Method] In this paper, an offshore wind power project design was taken as an example to do research on a new wind turbine foundation structure which was of large-diameter steel cylinder combined with jacket. Using finite element software PLAXIS 3D, overall stability calculations of the structure were carried out by adopting reasonable and feasible constitutive model and simplified form. Interaction between steel cylinder and soil was considered. Internal forces and displacements of wind turbine foundation were analyzed. Besides, solid model was established by using ANSYS and stress of components under extreme load combinations were calculated. [Result] The results indicate that the internal forces and displacements of the new combined type of wind turbine foundation are controllable. The new structure is applicative to the construction of offshore wind power on soft foundation and deep water area theoretically. [Conclusion] The research has certain reference significance to the development of the new type of offshore wind power foundation structure in the future.
2018, 5(3): 8-18.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.002
Abstract:
[Introduction] This paper is Part 2 of two papers, looking at applying European countries′ experience with economic regulation to one of the urgent challenges of China′s electricity systems: namely the effective connection of offshore wind. [Method] Using a methodology of comparative analysis of regulatory regimes, five components of regulatory regimes for offshore wind are defined and assessed for China: regulatory entity, degree of effective unbundling, tariff regulatory method and connection charging method and responsible entity. The paper analyses the changes to China′s network regulatory regime under way through Document No. 9 and related regulatory changes, including the introduction of a separate mechanism of economic regulation for China′s network companies, vividly described as "take control of the middle, release the two sides" . [Result] The paper finds that the new regulatory methods still need refinement in order to ensure that they fulfil regulatory objectives such as allocative and cost efficiency, as well as quality of service-including timely connection and full transmission of onshore and offshore wind power. Based on the experience of three European case studies (Part 1 of the two papers), representing the TSO model, the generator model and the third-party model in Part 1, the paper concludes that in principle, all three models could be applied in China. Bearing in mind some similarities and differences in assumptions and priorities between Europe and China, the paper recommends that China adopts the regulatory model best aligned with its priorities. [Conclusion] If the most urgent priorities are to improve the co-ordinated development of generation and network capacities and to provide good incentives for transmission investments, the TSO model would be most suitable; however, it would be vital to implement this model through an independent regulator, with legally binding network planning and clear liabilities for the network companies′ failure to connect in time, and also incentives to reduce curtailments.
2018, 5(3): 19-25.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.003
Abstract:
[Introduction] During the planning and design of extra-high and ultra-high voltage power grid, it is necessary to specialized research on electromagnetic transient simulation in order to evaluate the electro-magnetic transient characteristics of the related electrical equipment. [Method] This paper aims to put forward the key factors affecting the results of simulation. They mainly include the applicability of the simulation software and the completeness and accuracy of power flow and short circuit data of the power system, the physical structure and the electrical parameter information of the transmission lines, the main electrical equipment details of the substation. [Result] Based on the authority of the electromagnetic transient simulation software, we proposed the main conditions and requirements should be followed and illustrated the corresponding simulation results and application during the simulation of the electromagnetic transient characteristics such as the secondary arc current and recovery voltage, the power frequency over-voltage, operation over-voltage, and the small reactance installed the neutral point of the transformer, and so on. [Conclusion] The conclusions have been used in the planning of power grid and the design of power transmission and transformation project. And it can meet the electromagnetic transient simulation requirements for the power system.
2018, 5(3): 26-32.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.004
Abstract:
[Introduction] There is an obvious pressure energy loss in the electricity output process of Compressed Air Energy Storage (CAES) system, which is caused by pressure regulating valves. The existing of pressure energy loss results in an efficiency drop of CAES system. [Method] In this manuscript, the ejector technology was introduced into CAES systems to finish the air flow pressure regulating process. The target air flow with middle pressure parameter could be obtained by high pressure air flow ejecting low pressure air flow in ejectors. It causes less pressure energy loss than pressure regulating valves. In this investigation, we built and analyzed the performance of three CAES systems with three different pressure regulating methods, including "pressure regulating process only through valves" , "ejectors with fixed throat area" and "ejectors with adjustable throat area" . [Result] The results show that ejector technology can recover the pressure energy loss by increasing working air flow amount. There is about 2% percent additional air flow under ejector with fixed throat area. There is also about 4.1% percent additional air flow under ejector with adjustable throat area. The energy conversion efficiency of CAES system with pressure regulating valves is 59.26%, and those of CAES systems with fixed ejector and adjustable ejector increase to 59.60% and 59.97%, respectively. [Conclusion] The optimized CAES systems can be combined with renewable resource power plants to form united-power plants, which has positive effect in grid-connection of renewable power.
2018, 5(3): 33-41.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.005
Abstract:
[Introduction] The feasibility study of a 2×1 000 MW new generation ultra-supercritical unit with double re-heating cycles in a power plant in coastal areas is completed to promote the development of 1 000 MW new generation ultra-supercritical unit with double re-heating cycles at 630 ℃. [Method] The aspects of the main equipment parameters, specifications for main equipment, feasibility for main equipment, feasibility for auxiliary equipment, main system configuration, unit economy and thermal economy were analysized. [Result] The results show that 1 000 MW new generation ultra-supercritical unit with double re-heating cycles is feasible, which can be applied in our country. Compared with 1 000 MW ultra-supercritical unit with double re-heating cycles, 1 000 MW new generation ultra-supercritical unit with double re-heating cycles has a higher thermal efficiency, a lesser pollutant emissions, and a better economic profit. The 1 000 MW new generation ultra-supercritical unit with double re-heating cycles has a 48.72% thermal efficiency, a 252.48 g/kWh gross coal consumption rate and a 260.16 g/kWh net coal consumption rate, and is best in China. [Conclusion] Advanced martensitic heat-resistant steel G115 with independent intellectual property rights in China and extraction back pressure feed water pump steam turbine with a small generator can be used in 1 000 MW new generation ultra-supercritical unit with double re-heating cycles.
2018, 5(3): 42-47.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.006
Abstract:
[Introduction] N2O、C2H6、SF6 are used as refrigerants or working fluids in Rankine cycle. The critical and physical properties of these refrigerants make them as potential supercritical Brayton cycle fluids. [Method] By using a self-developed MATLAB program and REPROP physical property database published by the National Institute of Standards and Technology (NIST), thermodynamic analysis of supercritical N2O (S-N2O), supercritical C2H6 (S-C2H6) and supercritical SF6 (S-SF6) Brayton cycle was conducted with comparison to supercritical CO2 (S-CO2) Brayton cycle. Recompression cycle was selected for study, and a variety of conditions were calcuted with turbine inlet temperature in range of 300~550 ℃, pressure in range of 15~25 MPa, and pre-cooler outlet temperature of 32 ℃ and 47 ℃. [Result] Thermal efficiency calculation results show that S-N2O, S-C2H6, S-SF6Brayton cycles all exibit high efficiency, and the efficicy is higher than the coresponding thermal efficiency of S-CO2Brayton cycle, and the thermal efficiency is always improved with the increase of the inlet temperature of the turbine, but the increase of the pressure does not always increase the cycle thermal efficiency. The increase of the outlet temperature of the precooler leads to a significant decrease in the cyclic thermal efficiency.. Flow calculation shows that the total mass flow rate and turbine inlet volume flow rate of S-N2O, S-C2H6, S-SF6, S-CO2 cycle are much higher than steam Rankine cycle with similar parameters, but the turbine outlet volume flow rates of these four supercritical fluids are close to each other. [Conclusion] S-N2O, S-C2H6, S-SF6 and S-CO2 cycle all have potential application value.
2018, 5(3): 48-55.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.007
Abstract:
[Introduction] The large-scale grid connected of renewable energy represented by wind power results in frequent changes of generation load command in the thermal power unit. The debugging of coordinated control system parameters cannot satisfy the control quality of throttle pressure and the variation of the fuel quantity simultaneously. [Method] Based on the simple first order inertial object, adding the integral, pure delay and non minimum phase characteristics in turn, the constraint relation between the adjustment time of the typical objects and the maximum output of the controller was summarized gradually. [Result] Combined with the model of the boiler fuel quantity and the throttle pressure in the case of closed-loop control of the turbine-side in coordinated control system for thermal power unit, a formula is presented to describe the constraint relationship between the change of throttle pressure and fuel quantity under the disturbance of generation instruction. [Conclusion] The simulation results and actual operation data verify the accuracy of the formula which can meet the practical requirements.
2018, 5(3): 56-60.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.008
Abstract:
[Introduction] The low-temperature corrosion of the air preheater endangers the safety operation of the boiler in the power plant. It is necessary to analyze and compare the technical characteristics of different solutions of the low temperature corrosion about the air preheater in the coal-fired units. [Method] The article focused on the low-temperature corrosion solution about air preheater. Two solutions which were steam-air heater system and hot air recirculation system were used to increase the cold end air temperature of air preheater by technical analysis and energy consumption analysis. [Result] Steam-air heater system and hot air recirculation system have advantages. Although the initial investment of the steam-air heater system is relatively large, its system features have obvious advantages. [Conclusion] The application of the steam-air heater system is more extensive for the low temperature corrosion problem of air preheater.
2018, 5(3): 61-66.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.009
Abstract:
[Introduction] Optimizing output curve of thermal power plants by using pumped storage power plants is an important means to improve the economy of power system. [Method] In this paper, a mathematical model of combined optimal operation of pumped storage power plants and thermal power plants was established first. Then, an actual power system containing pumped storage power plants and thermal power plants was taken as an example for simulation. Finally, the mechanism of coal saving of combined optimal operation of pumped storage power plants and thermal power plants was revealed. [Result] The simulation results show that combined optimal operation of pumped storage power plants and thermal power plants reduce the coal consumption of power system. [Conclusion] We suggest that output curve of thermal power plants should be optimized by making full use of pumped storage to improve running efficiency of power system.
2018, 5(3): 67-71.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.010
Abstract:
[Introduction] With the continuous development of VSC-HVDC technology, it has become the mainstream of DC transmission technology. For long-distance, high voltage, high power demands for power transmission, ± 800 kV VSC-UHVDC transmission engineering applications are imminent. As the core part of the VSC-UHVDC converter station, the layout of the converter transformer is very important and will have a significant impact on the general layout of the whole station. [Method] Based on the technology of VSC-UHVDC, this paper analyzed single line diagram, the layout of converter transformer, layout of converter transformer square, and the layout of starting circuit. And according to the characteristics, this paper provided a superior design of converter transformer layout. [Result] The layout is highly reliable and can be implemented, saving the space and investment cost. [Conclusion] The research is instructive for the engineering application of the ± 800 kV DC converter station and has a wide range of engineering application prospects.
2018, 5(3): 72-76.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.011
Abstract:
[Introduction] In the freezing rain and snow climate environment, it is necessary to heat the transmission line to strengthen its ability of resisting accident caused by snow and ice disaster. DC ice-melting device has been using widely and effectively current years. [Method] This paper aimed to establish a feasible and meaningful technology to solve the problem of DC ice-melting device which adopted two independently sets of ice melting equipment, doubled the O & M cost, had worse economy, and need more investment and floor space. Wherefore, this paper proposed a feasible method which a main circuit topology of new model ice-melting device used for ice-melting and snow on both phase wire and ground wire, then it was introduced in this essay. [Result] The results we obtained prove that this technique is feasible and effective. [Conclusion] This technology provides great significance for further study on solving the problem of snow and ice overage on phase wire and ground wire, in reducing the investment on DC ice-melting device and in improving the capability of transmission system to resist the natural disaster.
2018, 5(3): 77-82.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.012
Abstract:
[Introduction] The p-y curve method has obvious advantages in calculating stress state of piles under horizontal displacement. [Method] This paper developed a new automatic p-y curve extraction program, which can obtain reaction force p through fitting and derivation of shear force. [Result] The results show that while improving the accuracy of the calculation, this program reduces the user′s experience requirement and it is worth promoting in project. [Conclusion] A three-dimensional finite element analysis of steelpile foundation in Guishan offshore wind farm project is carried out, the results verify the reliability of the extraction program in soil-pile interaction analysis.
2018, 5(3): 83-88.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.013
Abstract:
[Introduction] High big-span irregular structures are increasingly used in the power industry, and their structural selection is of great significance to process adaptability, structure safety and economy. [Method] Through±1 100 kV Changji DC Converter Station project, space tubular truss structure was introduced to be used in the indoor DC Hall structure design, which is a high big-span irregular electric structure. According to the electrical process layout and its loadings. This paper gave the process how to select the space tubular truss structural form, the structure characteristics and its technology advantages; the structure integral calculation and key component design calculation results were shown in the design; after comparing with the lattice grid structure form both in technical and economic aspect, prospects of using space tubular truss structure in high big-span irregular electric structures and its key matters in design was discussed. [Result] Analysis shows that the space tubular truss structure is a space self-stabilizing system with good structural safety, strong process adaptability, convenient processing and installation, simple and beautiful. [Conclusion] The space tubular truss structure will be a preferred choice for the design of high big-span irregular electric structures in the future.
2018, 5(3): 89-93.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.014
Abstract:
[Introduction] Several towers of some 110 kV or 220 kV transmission lines built in 1980s and 1990s were destroyed under typhoon strike. The reasons of towers collapse shall be analyzed for reinforce and rebuild transmission lines. [Method] Wind load calculation formula of transmission line for 1979, 1990, 2002 and 2012 China code were introduced. The differences of wind speed, height variation factor of wind pressure, shape factor, adjustment coefficient of wind load and icing load factor were compared, wind load of a tower section and conductor for four edition China codes were calculated. [Result] The results show that the 12 code's design wind speed is 5%~10% greater than that of 79, 90 and 02 code, the 79 code's tower wind load for tower height under 60 m is underestimated without considering adjustment coefficient of wind load and 1979, 1990, 2002 and 2012 code's wire wind load of 110 kV or 220 kV transmission lines are seriously underestimated without considering adjustment coefficient of wind load. [Conclusion] The difference of 79, 90, 02 and 12 code's wind load for tower and wire is mainly affected by wind speed return period and adjustment coefficient of wind load, which are main reasons for tower collapse.
2018, 5(3): 94-101.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.015
Abstract:
[Introduction] Building energy simulation is an important supporting tool for green building design and building energy consumption assessment. At present, building energy simulation software can't meet the needs of energy consumption analysis and cabinet level micro environment control design of prefabricated building. [Method] Thermal physical model of prefabricated building was proposed in this paper, then the energy consumption calculation software of prefabricated cabin building(PCES) was developed based on the physical model. Finally the software PCES was proved to reflect the energy-consumption distribution objectively in buildings by the project example. [Result] The results showed that a new way was put forward to solve the envelope of prefabricated cabin, cabin thermal condition and cabinet thermal environment, which was suitable for energy saving design and energy consumption analysis of engineering. [Conclusion] We demonstrate the feasibility of building parameter setting, energy consumption simulation and building thermal process and energy consumption analysis by PCES.
2018, 5(3): 102-105.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.016
Abstract:
[Introduction] This paper aims to do specially design for durability of concrete structure to improve the corrosion resistance of concrete which is in strong sulfate corrosive environment of saline soil in a power transmission project in Tibet. [Method] Analyzed the corrosion mechanism of sulfate to concrete and the influencing factors of the durability of concrete. At last found out the technical measures to prevent or reduce the erosion of concrete. [Result] Combined with the actual situation of the project, we finally determine the concrete mix ratio, and add anti-sulfate corrosion preservatives in the concretet to improve the durability of underground concrete structures such as pouring pile and cap foudation. [Conclusion] This work provides some guidance for the durability design of concrete under strong sulfate corrosive environment.
2018, 5(3): 106-110.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.017
Abstract:
[Introduction] In order to investigate the enrichment of Cl- in the slag water system, the physical model of Cl- concentration change in self-balanced slag system is established. [Method] Through steady and transient physical model analysis, the calculation formula of the concentration change in the slag water system was deduced in detail. The concrete engineering case was also calculated by using the deduced formula. [Result] The results show that Cl- will gradually enrich in the slag water system and gradually reach the equilibrium concentration after a period of time when the desulfurization wastewater is introduced into the self-balanced slag system. According to the domestic coal-fired power plant engineering data, the final Cl- equilibrium concentration is generally 2 to 3 times of desulfurization wastewater Cl- concentration. It reaches the final balance generally only within hundreds of hours. [Conclusion] The established model and calculation results are correct and effective, and can provide guidance for practical applications.
2018, 5(3): 111-114.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.018
Abstract:
[Introduction] The paper aims to solve the problem of system failure caused by quality destruction of valve cooling spray water in converter station. [Method] This article analyzed the water quality damage mechanism, analyzed the process of LCC valve cooling spray water to the pipeline damage, researched out the content needed to be removed. [Result] Propose an optimization reverse osmosis treatment plan for VSC valve cooling spray water. Efficient removal of the various factors in the spray water that damage pipeline. [Conclusion] The spray water will not scale on the cooling coils or generate other damage by treated with the solution, and ensures reliable cooling performance and stable operation of the valve cooling system.
2018, 5(3): 115-119.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.019
Abstract:
[Introduction] Air supported belt conveyor (ASBC) is a material handling device with advantages of steady operation, high efficiency, good environmental protection benefit, which has been used in grain storage, port and chemical industry fields. However, it is rarely used in coal handling system of power plant. The paper aims to inverstigate the application possibility of ASBC in coal handling system of power plant. [Method] Based on analyzing the operation principle and technical characteristics of ASBC, the economy comparison between ASBC and roller belt conveyor had been investigated. [Result] The result indicates that the ASBC has lower operation & maintenance cost, better economic performance in whole life cycle, and higher environmental benefits. [Conclusion] It is worthy to use the ASBC in coal handling system of power plant.
2018, 5(3): 120-126.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.020
Abstract:
[Introduction] Based on the unique location conditions of Dapeng New District, the technology of Wind Power, Solar Power and Energy Storage can provide multi-energy supplement technology mode for the charging infrastructure. [Method] In order to ensure the typicality of the benefit analysis, the article selected three representative charging infrastructure sites to construct multi-energy supplement devices. In order to comprehensively analyze the benefit of multi energy complementary model, this paper choosed three dimensions of economy, society and environment to analyze. [Result] In terms of economic benefit analysis, according to construction scale of the charging infrastructure, this papper built the model of electricity consumption and calculated power usage.In the condition of setting investment internal rate of return, this paper calculates the investment internal rate of return base on the operating income and the total cost. In terms of environmental benefits, this paper measures the clean energy power generation and quantizes energy conservation.At last the benefits of social are analyzed. [Conclusion] Comprehensive economic, social, environmental and other aspects of the benefit analysis, the use of multi-energy supplement to support the charging infrastructure power supply has a good demonstration.
2018, 5(3): 127-132,139.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.021
Abstract:
[Introduction] The traditional distribution network planning focuses on the necessity of power grid construction based on the operation problems and development demand of power grid, and the operation cost and reliability are ignored. It’s not conductive to the efficient operation of power supply enterprises. [Method] The concept of equipment utilization benefit was put forward, and on this basis, the evaluation model and optimal strategy of distribution network planning scheme based on lifting equipment utilization benefit were proposed. [Result] The results of example show that the evaluation model makes a comprehensive quantitative analysis of life cycle cost, safety, efficiency and benefits of different planning schemes, which makes the optimization results of planning schemes more scientific and reasonable. [Conclusion] This optimal strategy has the feasibility and the superiority, has provided the important basis for the actual distribution network planning work.
2018, 5(3): 133-139.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.022
Abstract:
[Introduction] With regard to the inspection and operations of the transmission overhead line, taking advantage of airborne LiDAR can attain higher efficiency, higher accuracy, and lower cost than utilizing traditional inspection mode. [Method] This paper was in the project setting of the Zhaoqing Power Supply Bureau transmission overhead line inspection and operations, moreover, taking the airborne LiDAR technology as the study object. Key techniques of data collection and data processing were analyzed and presented in the research. Data application mode of airborne LiDAR system in power line inspection was discussed. Also, combined with the practical experience, summary and propects were illustrated. [Result] This paper successfully verifies the application of airborne LiDAR system in power grid inspection, and accurately obtains information of defect points in the power grid corridor, including spatial information of defect points of scanning working condition, different working conditions, cross-over, and falling tree. [Conclusion] The analysis results can assist defect point management to effectively achieve expectations of power grid safety inspection.
2018, 5(3): 140-148,119.
doi: 10.16516/j.gedi.issn2095-8676.2018.03.023
Abstract:
[Introduction] The 2nd National Young Researchers Symposium on Engineering Risk Analysis and Management was held in Wuhan on March 30—31, 2018, aiming to promote development of new theories and technologies on engineering risk management and insurance and to provide a forum for academic communication for young researchers. [Method] The symposium was co-hosted by the Engineering Risk and Insurance Research Branch of China Civil Engineering Society, Wuhan University, China University of Geosciences (Wuhan), the National Key R&D Project (2017YFC1501300) and International Society of Soil Mechanics and Geotechnical Engineering TC304 (Engineering Practice of Risk Assessment and Management Committee). [Result] The major themes of the symposium include cutting-edge studies on theories and methods for engineering risk assessment and control. The symposium provides a great opportunity to young researchers in the engineering risk field to exchange ideas and to establish corporation with one another. [Conclusion] This is of great significance to the advancing in the field of engineering disaster prevention and risk control in China.
