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[Abstract](100) [FullText HTML] (23) [PDF 1810KB](32) [Cited By] ()
Introduction Under the trend of accelerating the clean transformation of coastal energy and adjusting the industrial structure, offshore wind power will become an important support for the safe, clean and efficient transformation of power energy in coastal provinces due to its rich wind resources, high number of utilization hours and convenient consumption. Method In this paper, the current situation and future development prospect of offshore wind power industry were analyzed, and the comprehensive cost reduction trend of shallow-water and far-reaching deep-sea offshore wind industry was predicted. Result The results show that whether the Guangdong sea area can realize connection to grid at a fair price during the 14th Five-Year Plan period is dependent on the average annual comprehensive cost reduction rate; some far-reaching deep-sea projects in Guangdong can achieve connection to grid at a fair price by the end of the 14th Five Year Plan period, and there is still room for cost reduction under the scale effect. Conclusion Offshore wind power industry chain of our country has been improved gradually, but there are still many key components and core technologies relying on imports, so it is necessary to carry out continuous localization research to effectively reduce the industrial costs.
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[Abstract](36) [FullText HTML] (32) [PDF 2342KB](3) [Cited By] ()
Introduction Large-scale connection of wind power to the power grid poses great challenges to the stability (especially frequency stability) of grid operation.In order to solve the problem of inadequate frequency regulation capability caused by large-scale connection of wind power to the power grid and improve the frequency adaptability of wind power grid connection, wind turbines need to have frequency regulation function and response timeliness. Method This paper adopted a frequency regulation system scheme based on rotor kinetic energy and pitch angle reserve, which could provide active support for the power grid quickly and accurately during the power grid frequency change. First, the main control algorithm was designed based on the theoretical analysis of inertia response and primary frequency regulation algorithm logic. Then, the functional verification was carried out on the co-simulation platform. Result Finally, the actual test is carried out in a project, and the simulation and test results show that the frequency regulation system scheme based on rotor kinetic energy and pitch angle reserve can cope with a variety of grid frequency changes and quickly provide active support. Conclusion The frequency regulation system scheme of wind turbines can perform a fast inertia response (with the response time less than 500 ms) and primary frequency regulation response (with the response time less than 5 s) under various frequency change conditions and provide active support for the power grid, which can help recover the grid frequency and effectively improve the frequency adaptability of wind turbines.
Research for Factors Influencing the Heat Dissipation Performance of Semi-Direct Drive Permanent Magnet Wind Generator
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[Abstract](52) [FullText HTML] (18) [PDF 3006KB](6) [Cited By] ()
Introduction With the development of wind power generation technology, the unit capacity of permanent magnet wind generator is increasing, and the heating power is also increasing. The heat dissipation of generator is facing unprecedented challenges. How to effectively solve the problem of generator temperature rise and heat dissipation difficulty has been the focus of our study. Method Based on the STAR-CCM+ software platform, an integrated numerical simulation method for generator heat dissipation and cooling was proposed in this paper. The reliability of the numerical calculation method was verified by comparing the calculated values with the experimental values. On this basis, a study was conducted on the internal temperature distribution law and the factors influencing the cooling system heat dissipation performance of the high power permanent magnet wind generator. Result Under the rated power, the highest temperature of the winding and stator core appear in the middle area. If the process conditions allow, the cooling water pipe should be as close to the winding as possible to take away more heat. The stator core temperature and winding temperature can be reduced significantly by increasing the total intake air volume of the generator. The intake air temperature has a linear relationship with the maximum temperature of the winding and stator core. For every 5℃ decrease in the intake air temperature, the maximum temperature will be reduced by about 1.4℃. Reducing the intake air temperature can improve the heat dissipation performance of the generator to a certain extent. The intake water temperature has a linear relationship with the maximum temperature of the winding and stator core. For every 5℃ decrease in the intake water temperature, the maximum temperature will be reduced by about 3.3℃. Reducing the intake water temperature can greatly improve the heat dissipation performance of the generator. In addition, the gap between the cooling water pipe and the stator core greatly hinders the heat transfer of the cooling water pipe. Filling the gap with materials with good thermal conductivity can effectively improve the heat dissipation performance of the generator. Conclusion The conclusions drawn in this paper can effectively guide the heat dissipation design of permanent magnet wind generator and ensure the safe operation of wind turbines in normal work.
Wind Power, Hydropower and Thermal Power Combined Low-carbon Maintenance Optimization Based on Continuous Hidden Markov Model
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[Abstract](21) [FullText HTML] (30) [PDF 2832KB](3) [Cited By] ()
Introduction In the context of the new power system, low-carbon maintenance of wind turbines and coordinated maintenance with conventional wind turbine generator systems (WTGS) need to be solved urgently. In this paper, taking into account the impact of multi-attribute meteorological factors and low carbon and economic needs, an optimization model for wind power, hydropower and thermal power combined low-carbon maintenance based on continuous hidden Markov model is established. Method Firstly, dynamic tracking of wind farm maintenance capacity was realized by taking rainfall, wind speed and lightning hazard degree as the observation sequence, taking maintenance capacity as hidden state sequence, and using continuous hidden Markov model (CHMM) process. Then, an optimization model for wind power, hydropower and thermal power combined low-carbon maintenance was constructed by taking the optimal maintenance capacity as the decision-making basis, taking the minimum total cost as the optimization objective, and taking the maintenance constraints and system control constraints into consideration. Finally, took the IEEE30-node system as an example. Result The results show that the proposed model has more significant economic benefits and low carbon characteristics. Conclusion The research in this paper has high theoretical value for the operation and maintenance of WTGS, and has strong engineering applicability.
Research for Vertical Bearing Characteristics of Top Grouting Jacket Pile Foundation in Clay Foundation
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[Abstract](27) [FullText HTML] (20) [PDF 1967KB](2) [Cited By] ()
Introduction The top grouting jacket pile foundation is a new type of foundation application for offshore wind power jackets on clay seabed. Since the grouting section can bear some loads, its stress and deformation mechanism is significantly different from that of conventional tubular piles. The existing design often ignores the bearing capacity sharing of each part of the foundation, and only treats the grouting section as a hollow tubular pile, ignoring the bearing capacity of the grouting section. Method This paper firstly compared the bearing capacity calculation formulas of existing ocean pile foundations and mesoscale foundations, and analyzed the applicability of various calculation formulas to top grouting jacket pile foundations. Then, a numerical model for top grouting pile foundation on clay seabed was established using the finite element method. The validity of the numerical model was verified by comparing with the field test and centrifugal model test results. Finally, based on the finite element results, the vertical bearing capacity calculation formula suitable for the top grouting pile foundation was analyzed. Effects of various soil strength distributions and length-diameter ratios on the foundation bearing characteristics and bearing proportion were explored. Result Results show that for the soil layers with linearly increasing strength and under various surface strengths, with the increase of the surface strength, the bearing capacity of the grouting section increases, but the bearing proportion of the grouting section gradually decreases. For the same soil layer, the bearing proportion of the grouting section gradually decreases with the increase of the buried depth of pile foundation (length-diameter ratio). Conclusion The bear loads of the grouting section can increase the vertical bearing capacity of jacket pile foundation, which is of great significance for the optimization of jacket pile foundation engineering.
, Available online , doi: 10.16516/j.gedi.issn2095-8676.2023.0000-00
[Abstract](44) [FullText HTML] (20) [PDF 1272KB](4) [Cited By] ()
Introduction In view of the economic benefits of AGC frequency modulation project of combined energy storage in Guangdong coal-fired power plant, the method of establishing typical engineering cases is demonstrated. Method The latest version of the south area of FM auxiliary market gains and settlement rule was summarized, the FM performance indexes of the lithium iron phosphate battery energy storage of Guangdong's typical 2×600 MW coal-fired units were calculated, and then benefit model was set up, the key parameters such as the cost, mileage, clearing price, operation time were estimated or assumed. Finally, under the contract energy management mode, the economic efficiency was calculated from the perspective of investors and the variation of financial indicators under different total investment, operation years and income sharing was analyzed. Result The results show that in the measured case, except for the first scheme, the IRR of capital in other scenarios all exceeds 7%. Conclusion The frequency modulation project of lithium iron phosphate battery energy storage in Guangdong has a good return on investment within four years. After that, investors can still be attracted to participate in this project with the decrease of total investment and the increase of share.