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RSS2021 Vol. 8, No. 4
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2021, 8(4): 1-8.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.001
Abstract:
Introduction The increasing proportion of installed renewable energy, represented by photovoltaic and wind power, and the continuous decrease of coal power make the power grid's demand for high-quality regulation resources continue to increase and bring new pressure to the peak shaving of nuclear power. It is urgent to improve the peak shaving capability of nuclear power through system upgrading, so as to improve the utilization efficiency, system safety and economy of nuclear fuel. Method The current situation of hydrogen energy preparation, storage, transportation and utilization was investigated and the suitable hydrogen energy storage technology route for nuclear power peak regulation was explored. Then the economic benefits of different hydrogen energy utilization technology routes were analyzed by taking the current operation situation of a nuclear power plant as an example. Result Hydrogen production used surplus nuclear power can improve the utilization efficiency of nuclear power and has good economic benefits and application potential. Conclusion With the improvement of technology and the reduction of equipment cost, hydrogen production using surplus nuclear power can not only improve the utilization efficiency of nuclear power units and obtain better economic benefits, but also contribute to the development of hydrogen energy industry. As a green energy with high energy density, hydrogen energy will play an extremely important role in energy saving and emission reduction and help achieve the goal of carbon neutrality.
2021, 8(4): 9-15.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.002
Abstract:
Introduction With the proposal of "peak carbon dioxide emission, carbon neutrality" and the deepening of energy reform, hydrogen energy, hydrogen energy as an important industrial raw material and energy fuel has been widely concerned and entered a rapid development period. Hydrogen energy industry chain mainly includes the hydrogen preparation, storage, transportation and utilization, which involves the integration and technological innovation of many industries. This paper is aimed at sorting out the current situation of hydrogen energy industry chain and analyzing the challenge faced by each node in order to provide suggestions for the development of hydrogen energy industry in the future. Method In this paper, we investigated the current technical status, analyzed the problems and challenges of the hydrogen energy industry chain, and put forward the relevant suggestions. Result Although China has technical reserves and industrial layout in all aspects of hydrogen energy industry, many technical shortcomings need to be solved. Among them, alkaline water electrolysis technology, high-pressure hydrogen storage technology, natural gas pipeline mixing hydrogen transportation technology has preliminarily met the application conditions. However, some problems in the technologies such as low temperature liquid hydrogen technology, hydrogen manufacturing with proton exchange membrane and fuel cell technology, hydrogen manufacturing with solid oxides and fuel cell technology remain to be solved. Meanwhile, compared with international advanced level, the development of hydrogen-fueled gas turbine in China is relatively backward. Conclusion As a strategic energy, the utilization of hydrogen energy is very important to promote the green transformation of energy and industry. But there are still many problems. Hence, it is necessary to make a reasonable layout, avoid the repetitive construction and introduction of low-end technology to accelerate the development of hydrogen energy industry.
2021, 8(4): 16-25.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.003
Abstract:
Introduction When inviting bids for domestic offshore wind power projects, the owner often puts forward requirements for the foundation top load and tower mass provided by the windturbine manufacture, and rarely put forward requirements for the the foundation mass provided by the design institute. During the detailed design stage, the windturbine manufacturer and the design institute optimize the tower and foundation respectively in turn, so it is usually difficult to get the global optimal design with the minimum total mass of the tower and foundation. Method An integrated test design method of offshore wind turbine tower and monopile was proposed. Through the test design of an offshore wind power project, several design schemes with different tower types, tower bottoms and monopile diameters were obtained, and the corresponding foundation top load, tower mass and monopile mass were obtained through load calculation and iterative optimization of tower and monopile design. Result The results show that the design with the smallest tower bottom load or tower mass is not the optimal one with the smallest mass of the whole support structure. The optimal support structure design with the lightest total mass of tower and monopile can be obtained by the experimental design method. Conclusion Based on the results of this paper, it is an effective method to reduce the cost of offshore wind power by adopting the integrated design of experiment of tower and monopile in finding the global optimum for the whole support structure. In the future offshore wind power bidding stage, the owner will formulate the optimal rules for the whole cost of the tower and monopile, and require the use of integrated design of experiment.
2021, 8(4): 26-31.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.004
Abstract:
Introduction As the foundation of one-step transportation and installation technology, composite bucket foundation of offshore wind power generation has been widely used in the development of offshore wind power. The main research content of this paper is to ensure the stability of composite bucket foundation during the construction. Method Through the transport field experiment of one-step transport installation ship, the real-time monitoring of tower drum and blade lifting and towing process during the construction of Xiangshui 25# wind turbine in Jiangsu was carried out. Result The results show that the dip angle of composite bucket foundation was smaller in the process of tower drum and blade lifting; during towing, the interaction force between drums, the roll angle and the height of liquid seal in tubes all met the requirements. Conclusion The results show that the composite bucket foundation had good stability during the tower drum and blade lifting process. In the towing process, the transport ship was closely fitted with the composite bucket foundation, which can ensure the stability of the whole structure in the transportation process. Moreover, the composite bucket foundation can provide stable buoyancy in the process of towing.
2021, 8(4): 32-36.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.005
Abstract:
Introduction Large capacity wind turbines and 66 kV power collection system will be selected for deep sea large-scale offshore wind power transmission. The wind turbines can be directly connected to the offshore converter station, so the offshore booster station can be cancelled and the intensive design can be realized. In this paper, the key electrical technology of intensive offshore converter station was preliminarily studied. Method On the basis of the existing offshore wind power flexible DC transmission technology, by studying the main circuit topology, core electrical equipment selection and platform layout optimization of the intensive offshore converter station, a feasible technical scheme for the key electrical technology was given. Result With the gradual popularization of offshore wind power 66 kV collection system, intensive offshore wind power flexible direct transmission will become the mainstream design scheme in the future. In this paper, the research conclusions with guiding significance were given for the key electrical technology points of intensive offshore converter station. Conclusion Compared with the traditional converter station, the intensive offshore converter station has obvious technical advantages. The research conclusions formed in this paper can provide technical support for the scheme decision-making and implementation of deep sea large-scale offshore wind power transmission project in the future, and have a good demonstration application prospect.
2021, 8(4): 37-42.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.006
Abstract:
Introduction In order to determine soil strength parameters more accurately and reliably, based on domestic and foreign engineering experience and research results, this paper proposes a practical method to obtain the undrained shear strength of clay and the friction angle of sand based on static cone pentration test (CPT) and standard penetration test (SPT) data. Method Firstly, it introduced the method of rapid stratification based on the four basic data of CPT, aiming to divide the sand layer and clay laye. Then the method of calculating the empirical coefficient N k t ![]()
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Conclusion The method discussed in this paper can provide more reliable reference for determining th design values of soil strength considering the existing condition in which offshore survey methods are limited and the equipment resources are relatively scarce.
2021, 8(4): 43-49.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.007
Abstract:
Introduction Due to the limitation of ecological protection and wind field boundary, there are obvious hill obstacles in the prevailing wind direction of some turbine sites, which affects the generating capacity and safety performance.This paper aims to study the methods to reduce the impact of the hilltops to the wind turbine. Method The numerical simulation method was applied for the the terrain with hilltop in the prevailing wind direction around the turbine site based on STAR-CCM+ software, analyzing the influence of sector management, elevating hub height and terrain optimization on the safety performance of the wind turbine. Result It's shown that sector management, elevating hub height and terrain optimization can improve the safety of the wind turbine. However, the method of double platform terrain optimization is more effective to improve the safety of the wind turbine for the project. Conclusion The results can provide reference for how to reduce the impact of upwind hilltop on the wind turbine.
2021, 8(4): 50-65.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.008
Abstract:
Introduction In order to improve the consumption level of renewable energy and measure the risks caused by the uncertainty of its output, this paper used the complementary and coordinated dispatch of different characteristics power as a means to improve the economy of system operation and promote the consumption of renewable energy. Aiming at fluctuation and uncertainty of renewable energy and load, the theory of conditional value-at-risk (CVaR) was introduced to evaluate risks caused by the uncertainty in system dispatching and operation. Method Using multi-scenario technology to simulate system uncertainty, a unit commitment and multi-scenario analysis reserve decision optimal dispatching model considering conditional value-at-risk (CVaR) was established, and the objective was to limit the risk level to an acceptable premise and minimize the system operation cost. Finally, the proposed model and method was implemented on GAMS (general algebraic modeling system) platform and solved with the mixed-integer linear programming CPLEX solver. Result Simulation calculations show that unit commitment and reserve decision of different types power can effectively improve system operation economy, reliability, and the consumption level of renewable energy. Conclusion The rationality and effectiveness of the presented model and method were validated by the numerical results of the improved IEEE 24 and the actual power grid system of a province.
2021, 8(4): 66-72.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.009
Abstract:
Introduction The double-turbine regeneration system can improve the energy efficiency of the unit. How to design the control strategy and ensure its safety, economy and effectiveness has been the prime focus of our group. Method According to the functional requirements of the double-turbine regeneration system, a corresponding the scheme of instrument arrangement of measuring points was designed, and a complete set of start-up, speed control, system protection and back pressure control strategies were put forward systematically. Result The control strategy has been successfully applied in a 1 000 MW Ultra Super-critical Pressure Unit, the results show that the control strategy can make the double-turbine regeneration system not only meet the feed water speed control, but also meet the requirements of coordinated control of steam extraction, exhaust and overflow, so as to ensure the stable, reliable and economic operation of the system. Conclusion The proposed control strategy has reference significance for further study on control strategy for double-turbine regeneration system.
2021, 8(4): 73-78.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.010
Abstract:
Introduction With the improvement of people's awareness of environmental protection, noise control in the gas turbine plant has become important in environmental protection. As a huge industrial building group of the gas turbine plant, how to reduce its noise and its impact on the environment inside and outside the plant has become the focus of environmental protection and noise reduction design of the gas turbine plant. Methods After analyzing the noise characteristics of the cooling tower, taking the layout of cooling tower group in Dongguan gas turbine power plant as an example, the cooling tower group was modeled by SoundPLAN. Results According to the simulation results, the noise control effects of different schemes of cooling tower groups are analyzed, and the advantages and disadvantages of each noise control scheme are put forward. Conclusion The proposed noise reduction scheme of the cooling tower group can be used as a reference for the design of similar power plants in the future.
2021, 8(4): 79-84.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.011
Abstract:
Introduction In order to meet the recent European power plant construction needs, it is urgent to understand the requirements of European pipelines and fittings standards in power plant engineering. Method Aiming at pipe fittings, this paper compared the European pipe fitting standards with the corresponding clauses of domestic pipe fitting standards. Result After comparison, the difference between the European standard pipe fitting standard and the domestic pipe fitting standard is obtained: the European standard pipe fittings are more comprehensive in the scope of use of the industry and the scope of material use; the dimensional tolerances, wall thickness tolerances at the welding ends and tolerance on the form of the European standard pipe fittings are more stringent than domestic standards; European pipe fittings strength calculation standards are more conservative and more safe; European pipe fittings have their own characteristics relative to national standard pipe fittings in terms of pipe end bevel, flow area, elbow bending radius, etc; in addition, pipe fittings entering the European market need to comply with the European Union's administrative directive PED. Conclusion Through the above-mentioned standard differences, we have basically mastered the basic requirements of European standard pipe fittings standards, which can provide guidance for the practical application of European standard pipe fittings in power station projects.
2021, 8(4): 85-94.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.012
Abstract:
Introduction Aiming at the current problems of the continuous update of the security requirements and low efficiency and uncontrollable effects of security rectification on-site operations for the power monitoring system, and the status quo of large area off-grid operation of some secondary equipment without effective rectification methods, secondary equipment centralized security operation and maintenance and key technologies of active perception, diagnosis and early warning are studied. Method Compliant grid-connected devices were unified deployed in substations, the technologies of deep belief nets multi-class support vector machine intrusion detection and adaptive probabilistic marking scheme IP traceback were used to filter recording data, active percept and retrospective diagnosis invaded threats, the risk early warning and comprehensive assessment technology based on combining with threat and adversarial analysis were adopted to carry out impact assessment and rating, and the existing recording master station system was used to expand the security operation and maintenance management business to form centralized operation and maintenance management model. Result Practical results show that this method can achieve the goals that the security system of substation secondary equipment is centralized managed and efficiency of operation and maintenance is higher. Conclusion The proposed method is effective and feasible to solve the problem of on-site security rectification of secondary equipment combined with the Guangxi power grid operation case.
2021, 8(4): 95-106.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.013
Abstract:
Introduction New energy power generation is intermittent and random, and its power is uncertain data, which will cause changes in grid voltage and frequency, thus pose a threat to the safe operation of the power system. In order to ensure the safety of grid voltage after large-scale new energy grid connection, considering the uncertainty of new energy generation, a reactive power optimization strategy of power grid incorporating renewable energy based on interval modeling is proposed. Method This strategy used interval to describe uncertain parameters in reactive power optimization model, and then established interval reactive power optimization model. The interval power flow algorithm based on optimization scenario was used to solve the interval power flow equation, thus obtaining the interval of state variables and determining the feasibility of control variables. On this basis, the improved particle swarm optimization algorithm was used to solve the interval reactive power optimization model, and the local search method and discrete variable cross-processing operation were added to the particle swarm optimization algorithm to improve optimization ability. In order to verify the effectiveness and superiority of the proposed method, IEEE 14 - bus and IEEE 30 - bus examples were used for simulation, and the proposed algorithm was compared with the adaptive genetic algorithm and the ordinary particle swarm optimization algorithm. Result The simulation results show that compared with adaptive genetic algorithm and ordinary particle swarm optimization algorithm, the improved particle swarm interval reactive power optimization strategy has a faster convergence speed, stronger optimization capabilities, and can effectively solve the discrete variables in the model. Conclusion Our data suggest that the proposed strategy can effectively solve the interval reactive power optimization problem and ensure the operation safety of grid voltage after large-scale new energy grid connection.
2021, 8(4): 107-114.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.014
Abstract:
Introduction Faced with the opportunities and challenges of the development of "Internet plus" smart energy, many energy companies are exploring transformation to build a prosperous energy ecosystem. One way is to build an open, shared, agile and flexible energy service platform by using Internet thinking and technologies. Method According to the fast expansion,variability,high reliability requirements of energy service platform, this paper analyzed the incompatibility of traditional monolithic architecture, and proposed the application of microservice architecture for platform construction. Then we introduced the methods and key points of the design and implementation of a micro-service-based "Internet plus" smart energy service platform. Result Based on this method, the author constructed the "Internet plus" smart energy service platform and built multiple energy Internet applications for different users, and implemented the dynamic expansion of business microservice successfully. Conclusion It shows that the "Internet plus" smart energy service platform based on microservice has good scalability, reliability, and deployment flexibility. The platform can support the rapid development of "Internet plus" smart energy business applications.
2021, 8(4): 115-122.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.015
Abstract:
Introduction To solve the problem of difficult site selection for grounding electrodes in HVDC transmission projects in Guangdong, this paper analyzes the connection of existing grounding electrodes to form a WAN grounding electrode for future DC project access to reduce the impact on electrical facilities and underground metal piping facilities around the electrode site. Method The feasibility of forming a wide-area grounding electrode by using existing grounding electrodes as sub-grounding electrodes was analyzed, several typical application scenarios of WAN grounding electrodes were proposed, and the natural shunted current calculation, current distribution averaging and multiple DC simultaneous operation conditions of each sub-grounding electrode were carried out. Result WAN grounding electrode can reduce the design requirements of Yuedong pole site and mitigate the impact of Yulongling grounding electrode on oil and gas pipeline and surrounding power system, and has the feasibility of implementation. However, the benefits are still not obvious without adding any current averaging resistors. Conclusion This study provides ideas and methods to reduce the difficulty of constructing new grounding electrodes by using WAN grounding electrodes.
2021, 8(4): 123-129.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.016
Abstract:
Introduction It is an inevitable trend for the current power grid construction in the urban area in domestic to adopt a compact indoor layout for the whole house in the power grid project. However, how to dissipate a large amount of heat emitted by indoor equipment without adversely affecting the surrounding environment is an issue worthy of in-depth study. As a cost-effective, noise-free ventilation scheme, natural ventilation should be given a priority. In order to study the influence of different schemes on natural ventilation of the indoor pre-insertion resistor circuit when other conditions remain unchanged, by changing the position and form of the ventilators, this paper discusses the cooling method of an indoor pre-insertion resistor circuit field in a VSC-HVDC converter substation in Guangzhou. Method Based on CFD, the temperature field and velocity field of the air flow in the factory building under the conditions of using streamline ventilator and thin ventilator were simulated respectively. Result The result of the simulation show that the natural ventilation scheme is feasible. It can also be verified that the streamlined ventilator increases the effective ventilation area, optimizes the indoor air flow field, reduces the internal ambient temperature of the indoor DC field by about 2 °C more compared with the thin ventilator, and can achieve a better overall cooling effect under the same ambient temperature. Conclusion It can be concluded that natural ventilation of the indoor pre-insertion resistor circuit is proved to be feasible, and heat dissipation effect of the streamlined ventilator is better than that of the thin ventilator in a specific environment. This project can provide reference and basis for similar VSC-HVDC converter substation in the future.
2021, 8(4): 130-134.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.017
Abstract:
Introduction Trenchless horizontal directional drilling is widely used in power cable line project to cross natural or artificial obstacles at present.Multiple cable protection tubes need to be laid successfully at one time in engineering applications. It is defined as multiple pipelines pulling crossing, and it is widely used because of it's excellent economic and environmental protection advantages. However, there is only the calculation method of single pipe pullback force of plastic pipe at present. This paper aims to study the calculation method of pullback force of multiple pipelines. Method This paper was based on a 220 kV cable line project in the Pearl River Delta. This project used horizontal directional drilling to cross the national first-class waterway for twice at the same place, and most of the crossing stratum was plastic clay layer. The calculation method of single pipe pullback force was used for analysis in the project, and the change curve of pull back force was measured on site during the implementation. Result The comparative analysis between theoretical calculation and measured results shows that: under the condition of plastic clay layer, the measured pullback force of multiple pipelines is 4～6 times that of single pipe with the same weight and envelope diameter. The straight-line pullback of pipelines is very important to reduce the pullback force and implementation risk. Conclusion In this paper, the concept of multiple pipelines pulling and the calculation reference value of pulling force in trenchless horizontal directional drilling crossing project can provide a reference for the crossing design and construction of similar projects in the future.
2021, 8(4): 135-141.
doi: 10.16516/j.gedi.issn2095-8676.2021.04.018
Abstract:
Introduction With the proposal of the goal of "carbon neutrality and peak carbon dioxide emission" in China, renewable energy power generation enterprises are facing the demands of rapidly expanding the installed capacity and vigorously developing investment and mergers and acquisitions. Under the background of the increasing shortage of existing subsidy funds in China, how to determine the subsidy income of renewable energy projects and adopt a reasonable method to evaluate the project has always been the difficulty of M&A decision. Method This paper focused on the new subsidy policy issued in 2020, calculated the cashing coefficient of renewable energy stock subsidy, and calculated the scale and time of subsidy cash inflow based on multi scenario assumption. Result Through the calculation of equal subsidy coefficient and investment valuation model, the end time of subsidy gap and the equal subsidy coefficient of each year are defined, and the best valuation method is selected based on the characteristics of renewable energy projects. Conclusion The offshore wind power and onshore wind power projects in some regions are valued using the valuation model, which provides important decision support for enterprise investment and mergers and acquisitions.
2021, 8(4): 142-147.
Abstract:
