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RSS2019 Vol. 6, No. 1
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2019, 6(1): 1-7.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.001
Abstract:
[Introduction] In this paper, the impact of natural gas system on the short-term scheduling with high penetration of renewable energy is illustrated and analyzed. [Method] The natural gas infrastructure constraints were integrated into the security-constrained unit commitment model, which minimized the expected operation cost while considering the variable wind power generation. Benders decomposition was applied to solve the problem with non-linear natural gas network constraints. [Result] Illustrative examples with 6-bus power system with 6-node natural gas system demonstrate the effectiveness of the proposed approach for analyzing the impact natural gas system on system scheduling with volatile renewable energy. [Conclusion] An optimal electricity portfolio of renewable and natural gas will continue to be an important direction for future energy system development.
2019, 6(1): 8-15.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.002
Abstract:
[Introduction] Large diameter cellular sheet pile cofferdam has been applied in practice recently due to the advantage of construction speed and less pollution to the environment. However, the design method of this cofferdam in soft clay is still in its infant. [Method] Taking a large diameter cellular sheet pile cofferdam in an artificial island project in China as an example, this study focused on the potential problems in its design in soft clay. Three different methods were used to calculate the stability of the cofferdam. These methods included China′s code method, Japan′s code method and three-dimensional finite element method. [Result] The results show that the earth pressures of foundation calculated by China′s code method are smaller than that of the other two methods. The overturning point is located at the un-overturning side of the cofferdam based on the results of Japan′s code method and the finite element method, whereas it is fixed at the front toe point of the cofferdam in China′s code. The safety factor of overturning failure by China′s code method is larger than that of the other two methods due to the different positions of the overturning points. [Conclusion] This showed that more work of the design code method and theory should be conducted on large diameter cellular sheet pile cofferdam in soft clay foundation.
2019, 6(1): 16-21.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.003
Abstract:
[Introduction] Chemical absorption based on amines is the most mature technology for post-combustion CO2 capture. However, this technology has the drawback of high energy cost, and developing new amine absorbent as an alternative of monoethanolamine (MEA) solution will be an important method to deal with this problem. [Method] In this review, the amine absorbent was classified into four categories according to the compositions, namely single amine absorbent, blended amine absorbent, phase-change amine absorbent and water-lean amine absorbent. The technological characteristics and research situation of these absorbents were introduced. [Result] The blended amines combine the advantages of different single amine, showing good CO2 capture performance with high reaction rate, high absorption capacity and low energy cost. Phase-change amine absorbent and water-lean amine absorbent are the new generation of absorbents, which have great potential, but still need to be further studied and improved. [Conclusion] Therefore, blended amine is a more mature solvent which has better advantages in industrial application in the near term.
2019, 6(1): 24-30.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.005
Abstract:
[Introduction] In order to ensure the safe and reliable operation of offshore wind farm, this paper analyzes the configuration scheme and operation mode of standby diesel generator set under the condition of isolated networks of offshore wind farm. [Method] Considering the diesel generator capacity accounting, reactive overvoltage, short-circuit current, harmonic analysis and protection setting under the condition of isolated grids of offshore wind farms, the rationality of the standby diesel generator set scheme was verified. [Result] The results show that the standby diesel generator set with rated capacity of 1.2 MW can meet the load requirements and voltage requirements of offshore wind turbines and offshore wind station under the condition of operation and maintenance, with half of the wind turbines connected to island operation mode and 2 Mvar reactors, also meet the 35 kV submarine cable reactive demand. At the same time, in order to avoid harmonic resonance, diesel generator is not recommended to provide yaw power for the wind turbines. For transformer of diesel generator and grounding transformer for offshore wind station, it is recommended to use recompression and overcurrent as main protection. [Conclusion] The configuration scheme of this paper provides a solution to the study of the isolated operation mode of offshore wind farms.
2019, 6(1): 31-35.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.006
Abstract:
[Introduction] For offshore VSC-HVDC converter stations, the environmental conditions are harsh and the construction is difficult. The selection of the main equipment has a great influence on the overall layout of the converter station. Reasonable selection of the key equipment will increase the reliability of the converter station and reduce construction costs, reducing maintenance work and the overall cost of the project. [Method] Analysing the composition of key equipment of the main circuit and the operational characteristics of offshore VSC-HVDC converter station. [Result] By focusing on the analysis of the type selection scheme and basis, we demonstrate the principle of equipment selection for offshore VSC-HVDC converter station. [Conclusion] The research conclusions is instructive and provide important design and application basis for the offshore converter station project.
2019, 6(1): 36-41.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.007
Abstract:
[Introduction] To improve the utilization efficiency and save the investment cost, the relay protection area and operation time in offshore wind farm need to be optimized. [Method] This paper eliminated the circuit breaker of 220 kV submarine cable outlet side, and steed the three-phase split current differential full range of rapid "T" zone protection for 220 kV submarine cable small bus. At the same time, the 35 kV station and 35 kV grounding transformer were combined, using simple 35 kV bus protection, and increasing the low pressure side of the main transformer zero sequence CT. [Result] The result shows that the optimization relay protection scheme can save a 220 kV circuit breaker and two sets of 220 kV bus differential protection investment. At the same time, the 70 m2 of space and corresponding investment cost of offshore substation can be saved. And the sensitivity and reliability of the protection configuration has been improved. [Conclusion] Finally, the optimal scheme of offshore wind farm relay protection is economical and reasonable, and it is expected to be applied in engineering practice.
2019, 6(1): 42-48.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.008
Abstract:
[Introduction] According to the actual operation of offshore wind farms, this paper has been integrate the monitoring systems of offshore wind, offshore substation, and onshore centralized control center. This paper proposes the smart offshore wind farm integration monitoring system. [Method] This article analyzed the system architecture, functional requirements, data processing, and security partitioning. In this way, the operation mode in which the offshore substation for a wind farm offshore wind farm was unattended and a land-based centralized control center was operated by few people can be achieved. The system showed that the several subsystems such as wind monitoring, offshore substation monitoring, video and environmental monitoring, wind power forecasting, cable fault monitoring, and equipment condition monitoring systems had been effectively integrated. [Result] It can provide complete monitoring functions for major electrical equipment, which can realize operational monitoring, operation and control, comprehensive information analysis and intelligent alarms, operation management, and assistance for these five applications. [Conclusion] Therefore, it can reduce the operating costs of wind farms and achieve the goals of advanced technology, complete function, reliable performance and economical rationality.
2019, 6(1): 49-54.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.009
Abstract:
[Introduction] This paper considered the requirements of production monitoring and operation management in offshore wind farms, and analyzed the overall design, functional requirements, and subsystem requirements of the auxiliary monitoring system for offshore wind turbines. [Method] This paper integrated the wind condition monitoring system (including vibration online condition monitoring system, wind foundation monitoring system, bolt load on-line monitoring system, blade condition monitoring system, generator insulation resistance automatic monitoring system, lightning remote detection system, gear box lubricant online monitoring system, box change operation monitoring system), video monitoring system, wind IP telephone system, extended functions, etc. [Result] The system incorporates multi-parameter information fusion to achieve fault diagnosis of electrical and mechanical characteristics of wind turbines, providing support for the performance comparison of wind turbines in offshore wind power big data centers in Guangdong Province. [Conclusion] In this way, preventive operation and maintenance can be realized, and a large number of corrective maintenance can be transformed into preventive maintenance, making it possible to intelligently monitor and early warning of wind farm.
2019, 6(1): 55-65.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.010
Abstract:
[Introduction] Wind energy is a renewable energy that has developed rapidly in recent years. The offshore booster station is the key equipment connecting the offshore wind farm and the onshore power grid. It plays the role of collecting and sending wind farm energy and raising the transmission voltage and reducing the transmission loss. At present, the design standards of domestic offshore booster stations are not systematic, and there are many situations where specifications coexist. It is necessary to conduct comparative studies on various standards. [Methods] Firstly, the classification of marine platforms and the classification of design loads were introduced. The design conditions and design methods of offshore platforms in different countries were discussed in detail. Finally, the rationality of earthquake-related correlations was compared and analyzed. [Result] Through the comparative analysis of different standards, there is a situation where ASD method and LRFD method coexist. The design of China′s offshore booster station chooses the route based on LRFD method. With the vigorous development of China′s ocean construction, it will also promote the relevant standards of offshore booster stations and the existing GB. [Conclusion] This study provides an important basis for the selection and rational application of standards.
2019, 6(1): 66-70.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.011
Abstract:
[Introduction] In order to understand the wake loss of offshore wind farm, the simulation results are verified to explore the variation law of offshore wake loss. [Method] In this paper, the PARK model was used to simulate the wake flow of a offshore wind farm in South China. The parameters of the model were optimized and the actual power output was verified. [Result] The results show that application of PARK model in wake simulation of offshore wind farms basically coincides with the actual power output. When wind turbines with 7D spacing in a certain wind direction, the distribution of main wind wake loss after the second row is about 30%. [Conclusion] PARK wake model can simulate the wake loss and calculate the power output in offshore wind farms. Sensitivity calculation of model parameters should be carried out to meet the actual conditions.
2019, 6(1): 71-75.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.012
Abstract:
[Introduction] In the near future, the possibility of launching inland nuclear power is less likely, so China′s nuclear power construction will be mainly based on coastal projects. As shoreline resources become increasingly scarce, it is increasingly difficult for coastal nuclear power plants to choose sites. Therefore, it is necessary to broaden the thinking and select sites scientifically. [Method] This paper recommended to focus on the coastal sub-region, adoptedd secondary circulation cooling technical scheme, and demonstrated the conditions of seismic geology, emergency evacuation and environmental protection, so as to make better selection of nuclear power plant site. [Result] The actual situation of a nuclear power project in western Guangdong shows that the new ideas and methods are helpful to optimize the site selection and scientific decision-making. [Conclusion] The research of this paper is of great reference to the site selection of subsequent nuclear power plants, and it is of great significance to make nuclear power layout more scientific.
2019, 6(1): 76-80.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.013
Abstract:
[Introduction] The paper aims to prove the reliable measures for water resources safety under the serious incident of inland nuclear power plant. [Method] By comparing the treatment results of the radioactive waste liquid in inland nuclear power and the national standards, it analyzed the treatment measures for the radioactive waste liquid under the serious incident of inland nuclear power, meanwhile, put forward the measures in order to further improve the safety and reliability of nuclear station, which were strengthening standby power supply, increasing standby water source and increasing waste liquid storage tank. [Result] The results show that under the serious incident, the radioactive material can be stored, blocked and treated in the plant by three radioactive material isolation measures of the containment holding, nuclear island plant retention and temporary storage in the pool at the plant. [Conclusion] CAP1000 inland nuclear power has perfect incident prevention and mitigation measures, which can effectively eliminate the possibility of releasing a large number of radioactive materials by the design. The inland nuclear power has the ability to ensure the safety of water resources under the serious incident.
2019, 6(1): 81-85.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.014
Abstract:
[Introduction] Due to the tendency of distributed photovoltaic power generation projects becoming more and more popular on the Internet, it is more and more important for the optimal design of various aspects of photovoltaic power generation projects. Based on a rooftop distributed PV power generation project in Shandong Province. [Method] This paper optimized the design of bracket inclination, component arrangement and bracket foundation selection. Through PKPM modeling and calculation, the paper emphasized on material usage and economy. [Result] The results show that when the concrete base weight is 2.4 m, the steel cost is 2.4 m, 2.8 m and 3.2 m, the total cost can be reduced by 0.55%, 27.5% and 37.9%. [Conclusion] We demonstrate that the steel volume, the concrete dosage and the cost are all optimized when the distance between the two columns is 2.4 m.
2019, 6(1): 86-91.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.015
Abstract:
[Introduction] In this paper, the thermal performance of a parabolic trough direct steam generation system (DSGS) is investigated. With the considerations of the stratified flow phenomenon and real flow patterns in the complex two-phase flow, the heat transfer progress in the DSG system is numerically studied, and the thermodynamic performances are revealed. [Method] Based on the flow pattern inside the trough collector, the two-phase heat transfer model in the trough-type heat collecting region was established, and the DSG process in the trough collector was simulated by MatLab programming. [Result] The variation of heat transfer characteristics of DSG technology along the length of the tube is revealed. The stratification phenomenon occurs in the two-phase flow region where the dryness is between 0.7 and 0.8. The occurrence of delamination reduces the heat transfer between the working medium and metal tube, which weakens the heat transfer effect. [Conclusion] This study provides a reference for the design and operation of DSG power stations, and verifies that the optimal arrangement of DSG collectors is recirculating.
2019, 6(1): 92-97.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.016
Abstract:
[Introduction] Coal blocking of pulverizing system is a big problem in power plant, especially for coal bunker. At present, there are many types of anti-blocking coal technologies on the market, but there are different opinions on the use effect. This paper aims to find a useful technology to prevent the coal anti-blocking. [Method] The paper studied the coal blocking reasons and same anti-blocking technologies, such as hyperbolic coal hopper, stainless steel hopper, hydraulic split board damper, reasonable design of falling coal pipe etc. The research focused on the technology of rotary blockage clearing machine. [Result] The results show that the technology has obvious effect on solving the problem of coal plugging in the coal bunker. But there are lubricating oil leakage at the joints between the static and dynamic parts, which shall be paid more attention on sealing selection. [Conclusion] The rotary blockage clearing machine technology in various anti-blocking coal technologies has obvious advantages and is worthy of popularization.The prevention of coal plugging in the pulverizing system is a comprehensive project. Regardless of the technology used, it is necessary to strengthen the scientific management of the coal source and coal yard to achieve the control of the moisture and viscosity of the coal into the furnace.
2019, 6(1): 98-103.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.017
Abstract:
[Introduction] The system commission of HVDC is used to verify the overall performance of the project. It is necessary to analyze the recorded data of the electric values collected during commissioning in order to obtain the conclusion. [Method] Some recorded figure were not easy to understand. The converter circuit needed to be analyzed to understand the mechanism. This type of analysis method was demonstrated by analyzing typical electric quantity recorded figure.The voltage and current values change greatly when the recorded wave was triggered, which was related to the complex change of the trigger angle caused by the control. During this period, the single valve intermittent conduction, the two valve intermittent conduction, and the valve commutation conduction generated continuous current.Using circuit theory and power electronics technology to analyze the state of the inverter, it was found that inverter was an AC-DC hybrid circuit during the single-valve intermittent conduction, regardless of leakage current of the shut-off valve, the DC voltage was constant. [Result] Based on the theoretical results, analyze the inverter side electric quantity recording wave when a low-voltage valve group of a UHV project is blocked, can be concluded that if the applied DC voltage is greater than the average DC voltage of the inverter, under the supplemental pulse mechanism a continuous current occur. [Conclusion] The process of voltage and current in the recording wave is well explained, and the necessity and correctness of the control behavior are verified. It can be used as reference for HVDC project commission analysis and provide support for commission conclusions.
2019, 6(1): 104-108.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.018
Abstract:
[Introduction] To overcome some shortcoming such as labor-intensity and inefficient-inspection in manual inspection, which is commonly adopted in the maintenance of the equipment in a HVDC valve hall, a intelligent monitoring system could be established. For omni-direction supervising as well as no effection on the equipment, layout-principles of infrared thermal imagers are proposed in this paper, based on current application of the infrared intelligent monitoring system in convertor stations. [Method] With analysis of the characteristics of the equipment in valve hall, the type and location of the camera probes was determinated. Then, a final scheme was shaped after the check of electrical distance, block and percision. [Result] An example of the infrared intelligent monitoring system is designed and checked in Dongfang convertor station, and some adjustment in the location and number of the camera probes is made. It is illustrated that an omni-directional monitoring system could be built. [Conclusion] This work provide some guidance for similar projects.
2019, 6(1): 109-113.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.019
Abstract:
[Introduction] In order to realize the standardized architectural design, factory processing and assembly construction for substations. [Method] The control building of 500 kV substation was taken as the research object, and the location of its industrial facilities was specified according to the functional requirements of the substation. Through comprehensive consideration of process flow, functional requirements, building materials, building technology, natural conditions and other factors, the selection of building materials, structural type selection, modular design, fire prevention, energy saving and other aspects were comparative analysis. [Result] The results show that the structure and wall integrated assembly system under the existing conditions is the most suitable for 500 kV substation. [Conclusion] The structure and wall integrated assembly system is feasible and representative.
2019, 6(1): 114-118.
doi: 10.16516/j.gedi.issn2095-8676.2019.01.020
Abstract:
[Introduction] Aiming at the problems of long inspection period, high operation intensity and no guarantee of objectivity and integrity of inspection results of the current tree barrier inspection of transmission line, this paper presents a method for three-dimensional modeling of transmission lines and intelligent identification of dangers of tree barriers based on three-dimensional laser point cloud data of fixed-wing UAV. [Method] Point cloud data of transmission lines was collected by three-dimensional laser scanner equipped with fixed wing UAVs, then extracted the power line points in the point cloud and simulate the complete power lines, calculated the euclidean distance between vegetation and power line protection area, and we can get the information of tree barriaer points or early-warning points through comparing the calculated results with the power line safety specifications. [Result] The test results showed that the error of automatic fitting power line is small, which meeted the requirements of tree barrier detection. [Conclusion] This method can extract power lines automatically, quickly and completely, and the extraction accuracy meets the accuracy requirements of tree barrier detection, greatly improved the quality and efficiency of existing tree barrier danger detection method of transmission line.
