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- S. ENERGY CONSTR. is a Peer-Reviewed journal started in 2014 which declared a Gold Open Access journal and dedicated to the free sharing and dissemination of knowledge in energy construction.
- 2023, indexed by Scopus
- 2022, indexed by EBSCO Research Database
- 2021, indexed by DOAJ(Directory of Open Access Journals)
- 2021，indexed by Japan Science and Technology Agency (JST).
About Journal
Bimonthly Publication，Start in 2014.12
Supervisor：China Southern Power Grid Digital Media Technology Co., Ltd.
Sponsor：
China Energy Engineering Group
Guangdong Electric Power Design Institute Co., Ltd.
Editor：Editorial Board of S. ENERGY CONSTR.
Publisher：Energy Observer Magazine Co., Ltd.
Honorary Chairman：DU Xianwan
Chairman：PENG Xueping
Co-Editor-in-Chief：YANG Yongping, FAN Yongchun
Associate Editor：ZHANG Chunwen
Editorial Director：ZHENG Wentang
Address：1 Tianfeng Road, Science City, Huangpu District, Guangzhou, P. R. China
Tel：+86-20-32116683; 32115630
ISSN 2095-8676
CN 44-1715/TK
CODEN: NFNYJK
Email：nfnyjstg@gedi.com.cn
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RSSThe call for papers focuses on academic frontiers and hot issues in the fields of "carbon peak and neutrality" and special columns, features, and special issues will be published irregularly.
- Special Issue of Large-scale Renewable Energy Hydrogen Production Technologies
- Special Issue of "Controlled Nuclear Fusion Power Engineering Technology" in May 2024
- Special Issue of ''Electric Power and Meteorological Technology'' in Jan. 2024
- Special Issue of ''DC Transmission Technology for New Power System Construction'' in Sep. 2023
- Special Issue of ''Offshore Wind Power Engineering Technology'' to be Published in Jul. 2023
- Special Issue of ''Hydrogen Energy Technology'' to be Published in May 2023
- Special Issue of "New Power System and Energy Storage Technology" to be Published in Dec. 2022
- Special Issue of "Low-Carbon Collaborative Transformation Technology for Thermal Power Generation Units" to be Published in Sep. 2022
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
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Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-139
Abstract:
Introduction Gravity energy storage, as a new form of energy storage, plays an increasingly important role in balancing power supply and demand, responding to intermittent energy fluctuations, and other aspects of the power system. Method Focusing on the gravity energy storage system based on ground structure and slope gravity energy storage, the paper analyzed in detail the research status of these two forms of gravity energy storage both domestically and internationally. Firstly, compared with traditional energy storage forms, the working principle and advantages of gravity energy storage were provided. Then, the research status and economic cost analysis of the gravity energy storage system based on ground structure and slope gravity energy storage structures were presented. Then, two typical types of slope gravity energy storage system structures, i.e. mountain mining car type and mountain cable car type, were introduced in detail, and the effect of parameters such as slope and weight on system efficiency and cost performance was explained. Finally, prospects and suggestions were given for the technical characteristics of gravity energy storage systems. Result The gravity energy storage system based on the ground structure is stable and has a high initial investment cost, making it suitable for users with large power fluctuations. The slope gravity energy storage features low construction cost and simple operation and is suitable for users in high mountain terrain with low power demand. Conclusion With the gradual maturity of gravity energy storage technology and its continuous cost reduction, it will play an important supporting role in the construction of power systems as a new type of energy storage in the future.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-147
Abstract:
Introduction By analyzing the history of human utilization of energy and the current situation of China's rural energy, this paper summarizes the main energy structure characteristics of rural areas in China. Method Through literature method, comparative analysis and other research methods, this paper explored the current situation of rural energy development and identified the existing problems and future development trends of rural energy development. Result From the perspective of the diversification of rural energy use, the usage of firewood is gradually decreasing, the development of rural biogas tends to be stable, the rural electricity consumption is becoming saturated after the completion of rural power grid transformation, the proportion of gas is increasing year by year with the implementation of the "West-to-East Gas Transmission" policy, the solar thermal utilization is steadily declining after the large-scale popularization, and the solar power generation is rapidly increasing with the breakthrough of photovoltaic power generation technology. Conclusion According to the current situation of rural energy in China, the traditional way of using rural energy has been gradually changed, and the development of new energy has been paid attention to. In combination with national policies, the corresponding energy characteristics of rural energy have been found, and the development trend of rural energy under the "dual carbon" goal in the new era of "energy saving and emission reduction" has been explored.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-108
Abstract:
Introduction During the hydrogen production process at hydrogen refueling stations, the mixture of ethanol and hydrogen can easily form a combustible gas, which may explode if ignited by sparks or high temperatures. In order to reduce the risk of explosion during hydrogen production and storage at hydrogen refueling stations, experimental research is essential. Method The explosion characteristic parameters were analyzed for hydrogen-ethanol-air mixture with different equivalence ratios and ethanol blending ratios at 1 bar and 400 K. By calculating the flammability limit and deflagration index of mixed gas, the degree of explosion hazard was evaluated, and effective safety measures were formulated to reduce the risk of explosion. Result The experimental research results show that an increase in the equivalence ratio will shorten the explosion time, making it ultimately tend to a stable value. The stable explosion times corresponding to hydrogen volume fractions (30%, 50%, 70%) are 0.03 s, 0.025 s, and 0.019 s. The maximum explosion pressure, maximum pressure rise rate, and deflagration index all increase and then decrease with the increase of equivalence ratio, reaching their peak at an equivalence ratio of 1.3. The flammability limit of the mixed gas continues to decrease with the addition of ethanol, and the decrease in UELmixture (upper flammability limit of mixture) is significantly higher than that in LELmixture (lower flammability limit of mixture). In addition, the maximum pressure rise rate and deflagration index show a significant decreasing trend with the addition of ethanol, and the maximum deflagration index calculated for this research is 11.85 MPa·m/s. Conclusion The research results have revealed the effect of equivalence ratio and blending ratio on the explosion characteristics of mixed fuels, providing a solid theoretical basis for reducing explosion risks in hydrogen production and storage processes at hydrogen refueling stations.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-179
Abstract:
Introduction With the depletion of fossil fuels and bio-fuels' emergence, ethanol-hydrogen hybrid fuel as a new generation of renewable clean fuel has attracted wide attention, so it is necessary to study the effect of ethanol-hydrogen premixed flame combustion characteristics. Method Based on the constant volume combustion system and combined with high-speed schlieren technology, the effects of the equivalent ratio and pressure on the laminar combustion characteristics of ethanol-hydrogen premixed flame were studied under the conditions of initial temperature of 370 K, hydrogen ratio of 50%, equivalent ratio of 0.7~1.4 and initial pressure of 1, 2 and 4 bar. Focusing on the propagation combustion characteristics of the flame, the laminar combustion velocity was calculated and its influencing factors were analyzed. The relevant reaction model was established with the help of Chemkin simulation platform, and the chemical dynamics of the laminar combustion characteristics were analyzed in detail by using Marinov's ethanol oxidation reaction mechanism. Result The results showed that the laminar combustion velocity was positively correlated with the adiabatic flame temperature and reached the maximum value around φ=1.1. The pressure significantly affects the net heat release rate, and the peak value occurs in the higher temperature region with a greater equivalent ratio. R1:H+O2⇔O+OH represents the most sensitive reaction which promotes the laminar combustion velocity of the flame. With the increase of pressure, the peak molar fraction of H, OH, and O free radicals gradually decreased and moved upstream. With the increase of the equivalent ratio, the molar fraction of H and O free radicals gradually decreased, and the molar fraction of OH free radicals first increased and then decreased. Conclusion The equivalent ratio, pressure and active free radicals have significant effects on the laminar combustion characteristics of ethanol-hydrogen premixed fuel, which can provide theoretical basis for subsequent studies.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-361
Abstract:
Introduction With the digital development of nuclear power, more and more nuclear power equipment data can be collected, and the operation and maintenance personnel can obtain the operation conditions of each equipment through data analysis. Accurate operation condition classification of nuclear power equipment is the basis for realizing the health assessment and anomaly discovery of nuclear power equipment. However, due to the wide variety of sensors inside the nuclear power equipment, the amount of data to be analyzed is too large, which brings great challenges to the manual classification of the operation conditions of nuclear power equipment. To achieve accurate and rapid automatic classification of nuclear power equipment operation conditions, this paper proposes a self-supervised learning algorithm for nuclear power operation condition classification based on TICC clustering. Method Firstly, the historical operation data of nuclear power equipment was normalized, and the elbow method was used to determine the optimal cluster number. Then the TICC clustering algorithm was used to classify the historical operation data of nuclear power equipment, and the data fragments of each condition were labeled by the classification results. Finally, the labeled condition data was used to train the convolutional neural network to obtain the condition classification model. Ultimately, the real operation data of nuclear power equipment was used for verification. Result The experimental results show that the classification accuracy of the proposed algorithm is 96.6%, and the classification needs only 3.2 seconds. Conclusion Compared with the K-means algorithm and TICC algorithm, the algorithm proposed in this paper has a great improvement in accuracy and classification speed, and the algorithm can effectively help nuclear power operation and maintenance personnel complete the classification of operating conditions of nuclear power equipment.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-099
Abstract:
Introduction The safe operation of nuclear power equipment is crucial for nuclear power plants (NPPs), and the losses caused by accidents are immeasurable. Therefore, effective anomaly detection for nuclear power equipment is necessary. Considering the limitations of fixed thresholds and manual detection methods, which are difficult to adapt to the dynamic changes in time series data, this paper proposes an anomaly detection method based on POT for multivariate statistical processes. Method This paper adopted PCA to construct an anomaly detection model, where the SPE statistic of the model served as the initial threshold for the POT algorithm. Subsequently, the portion exceeding the initial threshold was fitted with a generalized Pareto distribution to determine the final dynamic threshold. An anomaly warning was issued when the anomaly score exceeded the final threshold. By combining multivariate statistical process control (MSPC) with extreme value theory (EVT), this method used MSPC to discover anomalies in the operating data of NPPs quickly and improved the sensitivity and reliability of anomaly detection by modeling and analyzing extreme events, so that it can quickly detect anomalies in high-dimensional operating data of NPPs. Result In the simulation experiment results, the proposed method has a higher accuracy and recall rate than conventional multivariate statistical and POT methods. In experiments with actual operating data from different equipment in NPPs, the method's effectiveness in anomaly detection has been demonstrated. Conclusion By combining MPSC with EVT, the anomaly detection method proposed in this paper can not only detect anomalies caused by changes in data relationships but also avoid false detection in traditional MSPC by determining the final threshold using the POT method. This method can handle high-dimensional time series operating data of NPPs, improve the efficiency of anomaly detection, ensure the safe and efficient operation of NPPs, and improve their economic benefits.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-120
Abstract:
Introduction Natural gas hydrate is a clean energy source with great exploitation value, but the insufficient heat supply in the late stage of hydrate extraction leads to a low gas production rate. Reservoir modification can significantly increase hydrate reservoir permeability and improve heat transfer efficiency. Based on this, the effect mechanism of the gas production rate of fractured hydrate reservoirs under heat injection extraction mode after fracturing is analyzed. Method Hydrate reservoir after fracturing modification was taken as the research object in this paper, and a numerical model of thermo-hydro-chemical was established to simulate and analyze the effects of heat injection temperature, fracture aperture, and heat injection velocity on the gas production rate of hydrate reservoir, and then the orthogonal design of heat injection parameters was carried out. Result The results show that the effect of heat injection temperature, heat injection velocity, and fracture aperture on gas production rate can be divided into three stages in the process of fractured hydrate heat injection extraction, and the higher the heat injection temperature, heat injection velocity, and fracture aperture, the higher the gas production rate of hydrate reservoir. The orthogonal analysis of heat injection parameters shows that the heat injection temperature has a significant effect on the peak gas production rate, followed by heat injection velocity, and the fracture aperture has the least effect. Conclusion In this paper, the effect mechanism of gas production rate in heat injection extraction of a hydrate reservoir with a single fracture is clarified, and the efficiency of hydrate extraction is qualitatively evaluated, which provides some ideas for hydrate extraction in situ.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-255
Abstract:
Introduction Realizing peak carbon dioxide emissions before 2030 and achieving carbon neutrality before 2060 have been identified as important strategic goals for fostering high-quality economic and social development in China. Carbon sink is one of the crucial approaches to achieving carbon neutrality. Effective carbon sink incentive policies are the guarantee for achieving "carbon neutrality". Method By sorting out the development of ecosystem carbon sinks both domestically and internationally, the main problems in the development of carbon sinks in China were revealed, and a comprehensive understanding of China's carbon sink projects was established. By studying the mechanism for carbon sink projects to participate in carbon market transactions, channels for reaping benefits were clarified. Furthermore, through comparative analysis and research on pilot experiences, relevant conclusions were drawn by analyzing specific issues. Result As shown by the results, the development of carbon sink projects in China is mainly focused on forestry carbon sink, involving fewer other carbon sink projects. With middle-and-short term as the main project cycle, the growth rate of project development has slowed down. There are mainly three problems faced by China's carbon sink development: (1) the limited variety of methodologies and more limitations for developing carbon sink; (2) the long development process and imperfect mechanism; (3) the insignificant incentive effect of the carbon market after development. Conclusion The research indicates that China's future work on ecosystem carbon sink still faces huge challenges. To promote the high-quality development of carbon sinks, it remains necessary to expedite the adjustment and upgrading of carbon sink support policies, increase investment in carbon sink technology, and actively develop the “carbon sink +” industry.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-145
Abstract:
Introduction In the current context of increasing energy demand and environmental conservation advocacy, it is necessary to seek alternative energy sources for traditional fuel generators. Therefore, a study on the evaporation characteristics was carried out to identify fuel with superior properties. Method The droplet suspension experiments were conducted to investigate the evaporation characteristics of droplets of methyl oleate fuel with ethanol contents of 0%, 20%, 30%, and 50% at the ambient temperature of 673 K and 773 K. Results The results indicate that as the ambient temperature increases from 673 K to 773 K, the evaporation rate of the blended droplets rises. Furthermore, with the continuous increase in ethanol contents, the difference in droplet evaporation rates between the two ambient temperatures becomes more pronounced. At lower ambient temperatures, the evaporation process of the droplets is relatively stable, with the droplet evaporation rate showing a gradual decrease trend. The addition of ethanol leads to an extension of the droplet's equilibrium evaporation stage, increasing the evaporation time and inhibiting the evaporation process. Conversely, at higher ambient temperatures, the evaporation process exhibits greater fluctuations, with the droplet evaporation rate showing a gradual increase trend and reaching its maximum at the ethanol content of 50%. The addition of ethanol induces micro-explosion events, reducing the evaporation time and enhancing the evaporation process. Moreover, increasing the ambient temperature and ethanol content promotes the occurrence, intensity, and frequency of micro-explosion events in droplets. Conclusions Based on the experimental results of droplet suspension experiments on the evaporation characteristics of methyl oleate and ethanol blended droplets, this study provides important data support and references for related fuel research and applications.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-180
Abstract:
Introduction The study aims to comprehensively and systematically explore the current development status of molten salt reactor (MSR) technology, clarify the advantages of MSR as the fourth-generation nuclear power technology, and analyze the major challenges facing its commercialization. By analyzing the development history, technical classification, and research and development progress in various countries, the study provides valuable references for the future development of MSR technology. Method Using the research methods of literature review and comparative analysis, the development history of MSR technology was reviewed, the different types of MSR technology were classified in detail, and the latest progress in MSR technology research and development in countries such as the United States, China, Russia, France, and Canada was deeply analyzed. Meanwhile, based on actual cases such as the MSRE experimental reactor and the TMSR project, the key technical progress and major challenges of MSR technology were discussed. In addition, the impact of international cooperation and technological innovation on the development of MSR technology was also analyzed. Result It is found that MSR technology has been widely concerned globally due to its advantages of high safety and high fuel utilization rate. The United States has verified the engineering feasibility of MSR through the MSRE experimental reactor, and China has made important progress in molten salt preparation and purification in the TMSR project. Russia, France, Canada, and other countries have also made significant achievements in the field of MSR technology. However, the commercialization of MSR technology still faces many challenges, including supply chain construction, fuel supply, regulatory framework adaptation, waste treatment, safety assurance measures, and complex maintenance and operation. Conclusion Although MSR technology faces many challenges, its advantages in safety, fuel utilization rate, and design flexibility give it broad development prospects. International cooperation and technological innovation are key factors in promoting the progress of MSR technology. With the continuous advancement of related technologies, these challenges are gradually being resolved. In the future, MSR technology is expected to become an important support for the global energy structure transformation, playing a crucial role in improving fuel utilization, reducing nuclear waste generation, and enhancing reactor safety. As research deepens and technology matures, MSR technology is expected to achieve commercialization and contribute to the global clean energy transition.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-245
Abstract:
Introduction As an important carbon capture method in CCUS, pressure swing adsorption (PSA) CO2 capture technology has been widely used. However, the excessive capture energy consumption and operation cost restrict the promotion and implementation of the technology. How to accurately select the appropriate capture technology according to the actual situation and reduce the capture energy consumption is particularly important. Method This paper discussed the basic research and technical application of PSA technology at home and abroad, and analyzed the economy and prospect of PSA technology in petrochemical industry based on a practical application case of PSA technology for CO2 capture in a petrochemical enterprise. Result In this case, the project using PSA CO2 capture technology captured and stored about 800000 tons of medium-concentration carbon sources produced by the purification unit and low-temperature methanol washing unit of the coal-to-hydrogen plant. For 73.9% concentration of CO2 raw gas, the device achieved 96% CO2 recovery rate and 98% capture purity. H2S, CH4 and CH3OH are all controlled below 150 ppm, which can achieve about 56 kWh/t CO2 capture power consumption. It is found that pressure swing adsorption technology has the advantages of low energy consumption, low piezoresistivity, continuous process and strong stability of adsorbent, which shows the technical and economic feasibility. Since pressure swing adsorption is mainly physical adsorption, PSA may face the problem of high energy consumption and insufficient enrichment concentration for the treatment of low concentration of CO2 feed gas. Conclusion In summary, PSA CO2 capture technology is suitable for the treatment of medium concentration carbon sources, and has potential in thetreatment of exhaust emissions in petrochemical, cement and other industries in the future.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-343
Abstract:
Introduction The realization of dual carbon goals in the construction of a new power system necessitates the transformation of existing thermal power plants to accommodate peak load operations. The safety of thermal power units during flexible operation is a critical element for enhancing the overall stability of the power system. Air preheater is the key auxiliary equipment that affects the wide-load operation capacity of thermal power units. This paper addresses the challenges associated with flue gas temperature fluctuations and blockage and corrosion induced by excessive ammonia injection. It is very important to develop a real-time assessment and safety status monitoring model for dust and blockage of rotary air preheaters. Method Based on the big data of wide-load operation monitoring of 600 MW and 350 MW units in central China, the paper developed a model for air preheater blockage assessment based on approximation of the resistance coefficients in the case of various time scales. Furthermore, the flue gas temperature at the outlet of the air preheater and the cold end working temperature were used as monitoring indicators to count the proportion of parameters exceeding the limit in multiple load sections of the unit. Result The results show that, at a peak regulation load of 39%, there is approximately a 20% probability of temperature exceedance. In addition, the independent calculation of the blockage risk based on the two indicators may result in a certain degree of underestimation of its degradation rate compared to the calculation based on a joint distribution. Besides, with the verification of data from the two units, the method can quantify the short-term (within the soot-blowing cycle) and mid-and-long term evolution of the air preheater blockage. Conclusion This assessment strategy applies to other equipment and systems in thermal power plants, such as SCR denitrification systems and coal mills, providing a quantitative assessment of safety risks during peak load operation. It guides thermal power units to efficiently and stably cooperate with the new power system in dispatching.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-308
Abstract:
Introduction Wind turbine generator systems (WTGS) are prone to various types of failures due to the harsh operating environment. For the main bearing, a central component of the transmission system, it is difficult to detect and evaluate its early failure, and offshore operations are restricted by limited weather windows. How to accurately evaluate the operating conditions of the main bearings of offshore units has become a major difficulty for the industry. Method The study focused on the operation condition of the main bearing of an offshore direct-drive generator with a capacity of 7 MW. The transmission process of the wind wheel load in the transmission chain was deduced by the theoretical formula, and the radial load and axial load on the main bearing were obtained. Through the finite element calculation and analysis of the main bearing, the load distribution within the bearing raceway was obtained, which was mutually verified with the theoretical derivation, and the position of the vibration monitoring point was determined preliminarily. Result Finally, according to the position of the bearing measuring point, the vibration monitoring is carried out in the WTGS site, and a clear time-domain vibration curve is obtained. The vibration monitoring results such as the effective value of the vibration of the main bearing, the response frequency of the impact signal, and the acceleration envelope characteristics are analyzed. Combined with the detection results of the grease composition inside the bearing, the damage degree of main bearing's specific components is qualitatively judged. Conclusion This study has identified the measuring point position of the main bearing of multi-megawatt direct-drive offshore WTGS, and accurately assessed the operating condition of the main bearing, which can provide technical support for design and maintenance personnel.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-058
Abstract:
Introduction Energy is widely considered the fuel of industry and the lifeline of the national economy. The impressive economic and development achievement of Guangdong after reform and opening up relied heavily on the support and logistical backing from the development of its energy industry. Being a major energy consumer with limited resources and thus featuring low self-sufficiency in energy, Guangdong has always faced the threat of energy scarcity. After decades of development and transition, its energy sector is gradually evolving into a diversified new energy system composed of traditional thermal power, nuclear power, offshore wind power, and photovoltaic power generation. It has shifted from being a limiting factor in economic production to becoming an integral component of the province's high-tech manufacturing industry chain. Analyzing the economic contribution of energy sector from a macroeconomic perspective holds practical significance for formulating scientific energy industry development plans and promoting high-quality, coordinated development of energy and economy in Guangdong. Method Firstly, a research dataset was established by integrating the indicator data that represent the development of the energy sector and economy in Guangdong. Subsequently, both the vector autoregression model and the Feder two-sector production function model were employed to conduct a quantitative analysis of the overall economic contribution and spillover effects of Guangdong's energy sector. Result The analysis indicates that, during the late industrialization phase, a mutually reinforcing relationship existed between the energy sector and economic development in Guangdong. The production of the energy sector makes a significant overall contribution to economic growth, with notable spillover effects. However, the economic stimulus effect of energy investments is comparatively low. Conclusion The study empirically estimates the economic contribution of energy sector in Guangdong and based on the findings, suggests recommendations for high-quality development of Guangdong's energy sector. These can serve as references for the development planning and policy-making of Guangdong's energy development.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-294
Abstract:
Introduction Gas-steam combined cycle units have been widely used in combined heat and power, but their minimum power generation is limited by heat supply. Especially during the winter heating period in the north, gas-steam combined cycle units cannot reduce their output, thus impeding the grid integration of wind energy and causing wind curtailment. Method To address this issue, this paper investigates whether utilizing the operational flexibility of gas-steam combined cycle units in combined heat and power dispatch can promote wind power accommodation. To this end, a mathematical model was established to describe the diversified operating modes of gas-steam combined cycle units, then an economic dispatch model for combined heat and power considering wind power accommodation was constructed to co-optimize the unit commitment of coal-fired units, the operating modes of gas-steam combined cycle units, and the output distribution and reserve sharing among units. Result Case simulations revealed that during difficult periods of wind power accommodation, switching gas-steam combined cycle units from the two-on-one mode to one-on-one mode can reduce the wind curtailment rate by 1.28%, and switching them from extraction condensing to back pressure mode can reduce the wind curtailment rate by 4.55%. Conclusion Case analysis shows that making full use of the mode switching ability of gas-steam combined cycle units in combined heat and power dispatch can reduce the output of units during periods of high heat load, increase the wind power accommodation space to reduce the wind curtailment, increase the output ranges of units during periods of low heat load, thereby providing spinning reserve for the system and optimizing the reserve sharing among units.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-041
Abstract:
Introduction Transmission towers are crucial infrastructure in power systems, and their wind-induced collapse can cause significant losses to power systems. To find solutions to prevent wind-induced collapse of transmission towers, it is necessary to investigate the causes, contributing factors, and processes of wind-induced collapse. Method Research results on wind-induced collapse of transmission towers were reviewed from the perspectives of accident analysis, full-scale tests, wind tunnel tests, and numerical simulations. The relevant research results were analyzed and summarized, and recommendations for subsequent research were provided. Result The investigation revealed that the factors contributing to the wind-induced collapse of transmission towers include the presence of weak members in the tower body, defects in the calculation of wind loads on transmission lines in the code, and extreme wind loads not considered in the code. Conclusion It is recommended to research extreme wind load models, the impact of crosswind and torsional wind loads, accurate models of single tower and tower line systems, and improvement of relevant regulations in the code.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2024-001
Abstract:
Introduction The mangrove ecosystem has a high carbon sequestration capacity and is an important part of the global carbon cycle. Exploring its carbon sink potential can promote the mitigation and adaptation to climate change, providing a potential marine solution for China's carbon peak and carbon neutralization. Method In this study, the methodology of mangrove blue carbon assessment was studied to estimate the carbon reserve and carbon sink potential in Guangdong Province. The carbon reserve in mangroves in Guangdong Province was about 3 222 034.79 t C, of which the carbon reverse in vegetation was about 1 094 464.79 t C and the carbon reserve in soil was about 2 127 570 t C. Among different mangrove communities, the vegetation carbon reserve of Aegiceras corniculatum was the highest, reaching 1 508 930.79 t C, followed by Avicennia marina, Kandelia obovata and Sonneratia apetala, with carbon reserve of 1 508 930.79 t C, 859 115.16 t C, 193 295.54 t C and 660 693.3 t C respectively. Result According to the " Special Action Plan for Mangrove Protection and Restoration (2020-2025)", by 2025, 55.00 km2 of mangroves will be planted in Guangdong Province, and the carbon sink potential can increase by 36 171.49 t CO2-e ~99 890.67 t CO2-e, with great carbon sink potential. Conclusion This study can provide scientific basis for the afforestation of mangrove carbon sink in Guangdong Province, and is of great significance for China's carbon peak and carbon neutrality cause.
Strategies for Improving the Safety and Operational Reliability of High-Voltage Frequency Converters
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-184
Abstract:
Introduction "Energy saving and emission reduction" is the national technical requirement for industrial projects in recent years, and the frequency conversion technology can make process equipment adjust output under different working conditions, thereby saving resources. However, frequency converters are power electronic devices, and the failure rate of IGBT components is relatively high, and the requirements for the operating environment are harsh. Therefore, it is very important to improve the safety and operational reliability of high-voltage frequency converters. Method In the case of failure of individual power units of the high-voltage frequency converter, according to the neutral point drift technology, the position of the neutral point and the angle between the three-phase voltages are adjusted, so that the high-voltage frequency converter can bypass some faulty power units can still operate normally; Send the real-time status of the high-voltage inverter to the DCS, and realize the automatic bypass technology of the high-voltage inverter according to the logic configuration of the DCS; Set up a separate high-voltage inverter room to provide a relatively good operating environment for high-voltage inverters through air conditioning, ventilation, and air duct systems. Result After adopting the internal strategy and external environment strategy for the high-voltage inverter, the failure rate of the high-voltage inverter is reduced, and the safe operation time of the high-voltage inverter is prolonged. Conclusion The use of neutral point drift technology and the automatic bypass technology of the whole machine can reduce the failure probability and frequency of high-voltage inverters, and jointly improve the temperature and humidity conditions of the operating environment, which can increase the continuous and reliable operation time of the inverter, to greatly improve the safety and operation reliability of inverters.
Research on Carbon Emission Accounting and the “Dual Carbon” Transformation Path of Industrial Parks
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-311
Abstract:
Introduction As an important carrier of China's industrialization and urbanization, industrial parks not only provide a large amount of infrastructure and public services, but also become the main source of carbon emission in China and an important entry and focus point for achieving China's goals of carbon peaking and carbon neutrality. The paper proposes a theoretical research framework for analyzing the transfer process of carbon emission in industrial parks and optimizing the decision-making process of the "dual carbon" path, in order to achieve the refined management of carbon emission in industrial parks. Method Firstly, we analyzed the carbon emission characteristics of energy, industry, construction, transportation, and infrastructure in industrial parks, and established a carbon emission accounting model for industrial parks based on inventory analysis method. Secondly, considering the impact of factors such as gross industrial output value, industrial structure, energy structure, and energy consumption on carbon emission, we established a decomposition model of factors influencing carbon emission based on the STIRPAT method. Finally, we analyzed the mechanism and impact path of digital technology empowering green and low-carbon transformation, and proposed the optimization plan for decision-making of the "dual carbon" path. Result Taking Ganzhou Economic and Technological Development Zone in Jiangxi Province as the research object, we calculated the carbon emission and carbon emission intensity from 2020 to 2022, identified the main factors influencing the increase of carbon emission, and planned the "dual carbon" transformation path from four aspects: industrial structure, energy structure, policy system, and platform construction. Conclusion Research suggests that the proposed model can fully explore the information contained in statistical data of industrial parks and is scientific and effective, providing theoretical support for the decision-making of "dual carbon" transformation path and the construction of industrial internet platform for digital carbon management of industrial parks.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-277
Abstract:
Introduction This paper aims to explore a novel floating offshore photovoltaic system that not only effectively collects marine solar energy but also performs intelligent climate early warning. Method By integrating offshore photovoltaic technology with intelligent meteorological monitoring technology, we developed a viable intelligent offshore photovoltaic climate early warning platform. Firstly, the floating offshore photovoltaic platform was used to convert solar energy into electrical energy. Secondly, the intelligent monitoring system monitored ocean weather conditions in real-time and gave early warnings to improve the reliability of photovoltaic power generation. Result Tests show that the floating offshore photovoltaic system can effectively collect solar energy under different sea areas and weather conditions, and the intelligent meteorological monitoring system is used to timely give early warnings on the changes in marine meteorology. Conclusion This study finds that the platform has broad application prospects and market potential. It can provide references for the development of marine renewable energy and provide ideas and methods for related research and practice.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-347
Abstract:
Introduction With the increasing demand for flexible peak shaving of thermal power units and the rapid development of information technology, thermal power enterprises are shifting from the traditional operation and management mode toward a cleaner, more efficient, reliable digital and intelligent mode. How to improve the intelligence, precision and reliability of coal-fired units in the flexible peak-shaving process has become a key issue of concern to those in the industry. Method Aiming at the deep peak shaving of coal-fired units, this paper first summarized the typical problems in the process of flexible peak shaving, and analyzed the overall development of control theory applied to boilers. Based on this, this paper conducted a comprehensive analysis of coal-fired boiler flexible peak shaving algorithm models and their applications based on intelligent control from four aspects: optimization control of boiler combustion performance, precise control of wide-load denitration, boiler operational energy efficiency control, and monitoring and diagnosis of main and auxiliary machinery equipment. Result On this basis, the research progress and application effects of intelligent control theory and models in the flexible peak shaving of coal-fired boilers are discussed in detail. Conclusion At present, based on the common problems in the flexible peak-shaving process of coal-fired boilers, it is necessary to improve the accuracy of basic data acquisition, promote the complementary integration of data and knowledge, and strengthen multi-objective optimization control and DCS control system optimization on the basis of the stable combustion ability improvement of the combustion organization method. At the same time, it is important to consider the dialectical optimization relationship between peak shaving economy and unit life, thereby providing intelligent and precise solutions to improve the flexible peak shaving capabilities of coal-fired boilers.
Accepted Manuscript
, Available online ,
doi: 10.16516/j.ceec.2023-132
Abstract:
Introduction This paper mainly discusses the principles, methods and measures of lightning protection design of offshore floating photovoltaic power station to meet the safe operation of offshore floating photovoltaic power station in harsh climate conditions. Method Through the in-depth analysis of the marine environment, offshore floating photovoltaic power station structure and lightning characteristics, this study proposed a series of effective lightning protection measures. First, the use of metal structure could improve the lightning resistance capacity of the floating photovoltaic power station. Secondly, the installation of lightning rods could absorb and release lightning energy, reduce the impact of lightning on the power station. In addition, the establishment of the ground grid could effectively disperse the ground potential and reduce the risk of lightning strike. The use of insulating materials helped to reduce the direct invasion of lightning on the power station equipment. At the same time, the installation of monitoring equipment could be real-time monitoring of lightning activities, timely response measures. Regular inspection and maintenance was an important part to ensure the stable operation of the lightning protection system. Result The principle and implementation method of each lightning protection measure are elaborated, and some technical problems in lightning protection design are proposed. For example, how to ensure the good grounding of the lightning rod, how to choose the appropriate insulation material, etc. These achievements provide an effective reference for the improvement of the lightning protection capacity of the offshore floating photovoltaic power stations. Conclusion The results of this study will help to improve the lightning protection capacity of the offshore floating photovoltaic power stations and ensure the safe operation of the power stations. Based on full consideration of the marine environment, the structure of the offshore floating photovoltaic power station and the lightning characteristics, the appropriate lightning protection measures can effectively reduce the risk of lightning strike and ensure the stable operation of the power station. This is of great significance for promoting the development of renewable energy and protecting the environment. Further study can provide more reference and guidance for lightning protection design to cope with the more complex and harsh climate conditions in the future.
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2024, 11(4): 1-15
doi: 10.16516/j.ceec.2024.4.01
Abstract:
Introduction The new generation of the Internet of Things (IoT) is being fostered in the era of Internet of Everything (IoE), realizing its diverse development by selecting and combining new information, functions, and applications. The Energy Internet of Things (Energy IoT) which is based on IoT, envisions a future where physical things are connected through a dynamic network that exchanges information and energy. The Energy IoT is giving rise to new service models and methods for organizing, exchanging, and managing energy; It covers not only new concepts such as Energy-as-a-Service and Prosumer, but also leads to innovative applications in smart buildings, intelligent metering, smart grids, distributed energy, virtual power plants and more. Method This paper analyzed the current status of the Energy IoT, including its key industry drivers, potential technologies and applications, challenges and related research areas. Result This paper discusses and compares the definitions of Energy Internet and Energy IoT from academic and industry perspectives. And it analyzes some major stages and issues of future research in the Energy IoT. Conclusion This paper provides a useful reference for further research and practical applications in the field of Energy IoT.
2024, 11(4): 16-22
doi: 10.16516/j.ceec.2024.4.02
Abstract:
Introduction CO2 catalytic hydrogenation for fuel synthesis is an economically feasible and large-scale implementable technology for CO2 utilization, which can solve the problems of environment and resource shortage, and has gained wide attention in recent years. In this work, a microchannel reactor for CO2 catalytic hydrogenation to synthesize hydrocarbon fuels is developed. Method Based on the design concept of thermodynamic calculation, catalyst preparation, reactor design, structure optimization and performance testing, an anlysis was carried out. Result The thermodynamic analysis shows that hydrocarbon fuels can be produced from CO2 catalytic hydrogenation. Six iron-based catalysts are developed to improve the reaction rate of hydrocarbon fuel synthesis. Based on the computational fluid dynamics (CFD) simulation, the structure of the microchannel reactor is designed and optimized. The microchannel reactor has the advantages of simple-compact structure and strong heat-mass transfer capability. The experimental results show that the Zn-Fe catalyst exhibits the best performance of CO2 catalytic hydrogenation for the synthesis of low-carbon olefins. CO2 conversion and low-carbon olefins selectivity are 32% and 44% respectively. Conclusion The microchannel reactor designed in this work has the dual functions of CO2 utilization for hydrocarbon fuel synthesis, which is of great significance to China's response to climate change, the realization of the dual-carbon target and the development of hydrocarbon fuel industry.
2024, 11(4): 23-30
doi: 10.16516/j.ceec.2024.4.03
Abstract:
Introduction In order to solve the problems of high cost and complex preparation process of solar desalination devices, organic small molecule photothermal materials, which possess advantages such as light weight, low cost, simplified synthesis and purification processes, are selected as solar energy absorption materials. Method A kind of organic conjugated small molecule Y6 was combined with a low-cost cellulose paper to prepare a Janus structure water evaporator with wide spectrum absorption in the range of 350~1 000 nm and high photothermal conversion performance. Result The bottom surface of the evaporator has efficient water adhesion, facilitating rapid water collection, while the top surface has water repellency, which can achieve the self-floating ability. Moreover, each 3.14 cm2 device only needs 0.5 mg photothermal material to achieve a temperature of more than 70 ℃, demonstrating significant material-saving advantages. Conclusion Under 1.0 kW/m2 solar irradiation, the photothermal conversion efficiency of Y6-based evaporator is 64.4%, and the evaporation rate is up to 1.13 kg/(m2·h), which is obviously higher than that of the control cellulose paper evaporator. After solar evaporation desalination, the purified water obtained exhibits a significant reduction in ion concentration by 4~6 orders of magnitude compared to the initial simulated seawater. When the evaporator is integrated with a thermoelectric device, the evaporation rate reaches 1.02 kg/(m2·h) under 1.0 kW/m2 solar irradiation. Meanwhile, an output voltage of 55 mV is generated. This study demonstrates that the solar evaporator based on organic small molecule Y6 has a promising application prospect in the synergistic effect of photothermal water purification and thermoelectric power generation.
2024, 11(4): 31-41
doi: 10.16516/j.ceec.2024.4.04
Abstract:
Introduction With the establishment of the energy Internet architecture mainly relying on new energies, HVDC transmission has become an important way of power transmission, power grids present a new characteristic of "strong DC and weak AC". Synchronous condensers have unique advantages in dealing with the issue of "strong DC and weak AC" by virtue of their dynamic performance such as fast reactive power response and strong voltage support capability. Method To study the application of synchronous condensers in HVDC works, this paper summarized the development of synchronous condensers, introduced the current development status of several major types of synchronous condensers in China, such as synchronous condensers for transforming thermal power units, new-generation large-capacity synchronous condensers, distributed synchronous condensers, analyzed the working principle and dynamic characteristics of synchronous condensers. Then the paper summarized the virtues of synchronous condensers when compared with other reactive power compensation devices such as SVC, the application scenarios, existing configuration strategies of large-capacity synchronous condensers and distributed synchronous condensers. Result Finally, a simulation model of DC transmission system with synchronous condensers is built on the PSCAD/EMTDC platform. The simulation verify the suppression capability of synchronous condensers for commutation failure at the sending end and transient overvoltage at the receiving end caused by commutation failure, as well as the dynamic reactive power compensation capability under lagging phase operation. Conclusion The analysis shows that synchronous condensers have adequate suppression of transient overvoltage and commutation failure and their reactive power response speed and dynamic reactive power support capability will not be affected by lagging phase operation, which contributes to their prospect of engineering application for steady-state compensation in converter stations.
2024, 11(4): 42-53
doi: 10.16516/j.ceec.2024.4.05
Abstract:
Introduction With the advancement of the "dual carbon" goals and the introduction of new energy allocation and storage policies in various regions, there is a need to further clarify the role of distributed energy storage in the new types of distribution networks and the configuration of associated energy storage system. Method This paper began by summarizing the configuration requirements of the distributed energy storage systems for the new distribution networks, and further considered the structure of distributed photovoltaic energy storage system according to different application needs. To maximize the economic aspect of configuring energy storage, in conjunction with the policy requirements for energy allocation and storage in various regions, the paper clarified the methods for configuring distributed energy storage systems and summarized the commonly used algorithms for determining the location and capacity. Based on this, research suggestions were proposed. Result Proper configuration of energy storage should be based on clear demands, selecting the appropriate topology and offering a configuration plan that is optimized by comprehensively considering indicators such as power supply stability, security, and economic efficiency of the distribution network. Conclusion Distributed energy storage technology is the key aspect of the new distribution networks and an essential means to ensure the safe and stable operation of distribution networks. To harness its full potential, further research into its optimal configuration and related control technologies is necessary.
2024, 11(4): 54-64
doi: 10.16516/j.ceec.2024.4.06
Abstract:
Introduction Compressed air energy storage (CAES) is a technology for storing electrical energy on a large scale, only second to pumped storage in terms of scale. The gas storage device is an important component of CAES. The gas storage facilities of compressed air energy storage power plants that have been put into commercial operation domestically and abroad are mostly natural geological structures such as salt caverns and abandoned mines. Large-scale, long-term compressed air energy storage requires more economical and widely applicable gas storage facilities. Method Artificial underground cavern gas storage facilities largely freed compressed air energy storage power plants from the reliance on specific geological conditions, becoming a strong support for the large-scale construction of long-term compressed air energy storage power plants. However, there were few research achievements in this field domestically and internationally. Understanding the research status at home and abroad, summarizing advanced experiences from other industries, and clarifying the challenges that need to be addressed urgently in this field had significant implications for the large-scale construction of compressed air energy storage power plants. Result There are significant differences in the operating characteristics between artificial underground caverns in compressed air energy storage power plants and conventional artificial caverns such as natural gas storage facilities and hydroelectric water conveyance tunnels, and there is a lack of mature design methods and regulations for this field, with many technological challenges still awaiting resolution. This paper reviews the characteristics and key research contents of underground artificial caverns in compressed air energy storage power plants. Conclusion Prioritizing safety, considering cost-effectiveness and fostering innovation provide a guarantee for the independent development of the underground hard rock gas storage facilities for compressed air energy storage power plants. This technology holds practical significance in enriching China's energy storage and power generation experiences, and improving new power systems. If this technology matures, it can provide strong support for the construction of a new power system in China.
2024, 11(4): 65-75
doi: 10.16516/j.ceec.2024.4.07
Abstract:
Introduction In response to the inability of existing communication conditions to meet the intelligent O&M and ecological monitoring needs of offshore wind farm, this article explores and proposes a 5G customized network scheme to solve the problems of poor signal accessibility, incomplete network coverage, and low smoothness in offshore wind farms. Methods In this paper, a comprehensive O&M and monitoring scheme was proposed by using 5G customized network technology, which was as follows: through the deployment of 5G macro base stations outdoors, 5G indoor distribution in towers, and underwater laying of optical networks, the 3D coverage of wind farm communication networks was realized; Based on 5G slicing technology, one network could be used for multiple purposes to meet the needs of offshore wind farms for network differentiation; computing nodes were deployed in the centralized control center computer room, and private network data was forwarded through the edge UPF (user plane function) to achieve computing-network integration. Result The intelligent management and ecological environment monitoring scheme for offshore wind farms based on 5G technology proposed in this article has been piloted and tested based on the project. The test results show that the maximum effective coverage radius of 5G base stations reaches 11.3 km, and the stable transmission uplink rate reaches 5 Mbps, meeting the needs of observation data return and unmanned ship video return in the sea area. By deploying two 2.1G 8TR enhanced base stations on the booster station and wind turbine to enhance sea area coverage, the pull-net test around the wind farm verified that the 5G private network can effectively cover wind farms, with a coverage rate of 98.4%, which can basically meet the coverage needs of the entire wind farm. Conclusion This scheme utilizes a 5G private network to cover the sea area of the wind farm and achieves underwater communication through STN (Smart Transport Network) and underwater optical networks. Consequently, it innovatively constructs a 3D ocean monitoring and communication network, laying the communication foundation for the intelligent management and ecological environment monitoring of offshore wind farms.
2024, 11(4): 76-87
doi: 10.16516/j.ceec.2024.4.08
Abstract:
Introduction With the continuous increase of offshore wind farms, conflicts in the use of marine areas has become increasingly severe. The integrated development of offshore wind power and aquaculture has attracted growing attention, with various structural designs for wind turbine foundations integrated with aquaculture cages being proposed. However, most of these designs are still in the conceptual stage and far from practical engineering applications. Method Based on the requirements of equal netting mass, equal biomass of marine growth attached to the netting, and equivalent hydrodynamic performance of the netting, the paper introduced an efficient method to calculate the equivalent loads of the cages. Considering the design loads of a 14 MW wind turbine and marine hydrological conditions, a jacket foundation structure suitable for the 14 MW offshore wind turbines was designed, integrating internal and external aquaculture cages to propose two integrated systems combining jacket foundations and marine aquaculture cages. Using the Morison model and considering the impact of nonlinear waves, static analyses of different designs were conducted in SACS based on the proposed equivalent modeling method for the cages. Result The study shows that the integration of internal and external cages with the jacket foundation has little to negligible impact on the first and second order frequencies of the overall system and a more significant effect on the third order frequency. The rotation condition is the controlling case, and after adding internal and external aquaculture cages, local reinforcement of the jacket foundation is required. Computational results for the integrated designs of the 14 MW offshore wind turbine jacket foundation with internal or external cages meet the regulatory design requirements. Conclusion The analysis results provide a reference for the engineering application of the integrated system design of offshore wind turbine foundations and marine aquaculture cage systems.
2024, 11(4): 88-101
doi: 10.16516/j.ceec.2024.4.09
Abstract:
Introduction Aiming at the characteristics of offshore converter stations, the design scheme for wireless communication system of offshore converter station is proposed. Method By analyzing the characteristics and current application of offshore wireless communication technology and considering the requirements of equipment operation, station warning and personnel activities of offshore converter stations, the configuration scheme for the wireless communication system of offshore converter stations was proposed. Result Through the NAVTEX system, the requirement to receive weather and safety information is realized. Through the radar optoelectronic system and VHF ship to ship communication system, the requirement for vessel caution and expulsion is realized. Through UHF cluster intercom system, WiFi and mobile communication system, the daily communication requirement of personnel is realized. Through the lifeboat emergency communication system, microwave transmission system and satellite communication system, the requirement of personnel emergency avoidance is realized. Conclusion Therefore, the system can realize the basic communication requirements during the daily operation and maintenance of offshore converter stations, ensure the safety of equipment and personnel, and provide guidance for the design of wireless communication systems for offshore converter stations.
2024, 11(4): 102-110
doi: 10.16516/j.ceec.2024.4.10
Abstract:
Introduction In order to realize the goal of "dual-carbon", the green and low-carbon transformation of power supply side is the key to realize the green and low-carbon transformation of Guangdong, and at the same time, the construction of a diversified power supply support system with a high proportion of new energy is also the most important task for achieving a new type of power system in Guangdong. Therefore, it is of great significance to plan the carbon neutral power supply structure of Guangdong in advance. Method Based on the study of the prospective energy supply and demand pattern of Guangdong Province, this paper integrated the low-carbon transformation and energy security, considered the constraints from the proportion of non-fossil energy consumption, resource conditions, and the balance of power supply, and proposed a carbon-neutral power supply development idea for Guangdong, analyzed different transformation paths, and put forward relevant suggestions. Result The study shows that during the period of carbon neutrality, the total installed capacities of power supply in Guangdong Province is expected to reach about three times of the current installed capacities; the main body of power supply will be transformed from the current combination of "thermal power + nuclear power + external power supply" to "new energy + nuclear power + external power supply"; The proportion of non-fossil energy installed capacity will reach 80%, of which the proportion of new energy resources in the province will reach 50%. Conclusion The prospect of power structure adjustment in Guangdong Province seems optimistic. However, this process still faces many challenges from policy, technology and market, etc. It is suggested to pay attention to the role change of thermal power in the power system, safeguard the key factors of non-fossil energy development, and emphasize the building of regulating capacity for new power system; in order to meet the demand for electricity consumption in Guangdong twice as much as the status quo during the period of carbon neutrality, it is even more important to pay special attention to technological innovation issues leading the clean and low-carbon transformation of power supply structures, and through scientific and technological innovation, to promote the exploration of new energy types and new energy technologies towards the development of greater energy density and more efficient energy conversion.
2024, 11(4): 111-117
doi: 10.16516/j.ceec.2024.4.11
Abstract:
Introduction Under the vision of carbon peak and carbon neutralization, the construction of the new power system substations is imperative. Method To promote the transformation of traditional substations to new power system substations, a full-lifecycle green and low-carbon construction scheme for new power system substations was proposed. Focusing on electrical equipment, building structures, building equipment and integrated energy, the carbon emissions throughout the entire life cycle of substations were reduced, and the new power system substations were constructed and operated in a green and low-carbon manner. Result The results show that compared with conventional substations, the proposed green and low-carbon construction scheme not only improves the development and utilization of renewable energy and accelerates the low-carbon upgrade of power grids, but also promotes energy saving and consumption reduction of power grid equipment, reduces carbon emissions and O&M costs of substations, and improves the utilization level of basic resources of substations, thus improving the comprehensive economic benefits of the substations. Conclusion The proposed green and low-carbon construction scheme has certain universality and replicability. It can provide theoretical and practical guidance for the transformation and transition of substations, and lay the foundation for the low-carbon development of the power grid.
2024, 11(4): 118-126
doi: 10.16516/j.ceec.2024.4.12
Abstract:
Introduction In order to improve heat exchange efficiency, the condensate pipelines, main water supply pipelines drain pipelines and partial extraction pipelines of nuclear power plants are all coated outside the pipelines. At present, the test methods of ferromagnetic pipelines are mainly conventional ultrasound and ultrasonic guided waves. These test methods are limited by the detection environment and preconditions, which increase the difficulty of test. In order to improve the test efficiency of pipelines with insulation layer, we shall enrich technical methods, shorten maintenance period and improve economic benefit of nuclear power plant. Method This paper mainly studied the feasibility and reliability of pulsed eddy current testing method under low frequency electromagnetic interference in nuclear power plant, and used the measured and calculated values of the induced voltage to establish the optimal parameter inversion problem. In combination with the coupling relationship between the parameters and based on the time-domain analytical solution of the pipeline pulsed eddy current field, the paper established the specific relationship between the measured value and the calculated value of the induced voltage, and established the optimization parameter inversion problem. In combination with the coupling relationship between the parameters, the paper proposed a pulsed eddy current detection method for in-service operation and maintenance of insulated pipes in nuclear power plants. Result Using the pulsed eddy current detection method for the relative wall thickness of ferromagnetic pipelines proposed in this paper, in-service sample pipelines of nuclear power plant are tested and the testing result is compared with conventional ultrasonic testing. The error of the two testing results is about 5%. Conclusion The testing results of impulse eddy current testing are reliable and it is suitable for non-destructive testing and evaluation of nuclear power plant ferromagnetic pipeline wall thickness corrosion thinning.
2024, 11(4): 127-136
doi: 10.16516/j.ceec.2024.4.13
Abstract:
Introduction In the low-voltage distribution network, the residual current protection device, as an important guarantee of electricity safety, can reduce the harm caused by the leakage fault of electrical appliances and prevent human electrocution accidents. The current residual current protection device relies on the residual current signal size as the basis for the action of the protection mechanism, but has no function to identify the electrocution characteristics. To address this problem, this paper proposes a method for electrocution signal feature extraction and electrocution diagnosis in low-voltage distribution networks based on wavelet decomposition and denoising, as well as GRU. Method In this paper, the residual currents collected from electrocution experiments were pre-processed by downsampling and discrete wavelet denoising; The time and frequency domain electrocution characteristic parameters of the residual currents were extracted by the sliding window method, and the Fourier transform was used to extract the characteristic parameters of residual currents to the second harmonic amplitude. All the extracted feature parameters were used to form a high-dimensional feature space vector; which was subject to dimensionality reduction using the method of principal component analysis to obtain a new set of three-dimensional feature vectors. A diagnostic model for electrocution was established, and the three-dimensional feature vectors representing electrocution features were input into the model. Comparison experiments were conducted on electrocution signals using five different electrocution diagnostic models, such as recurrent gated network (GRU). Result The experimental results show that the convergence of the GRU-based electrocution diagnosis model is good, and the recognition rate reaches 98.33%. Conclusion The method provides new insights for the research and development of a new generation of residual current protection devices and offers an effective guarantee for electrical safety.
2024, 11(4): 137-143
doi: 10.16516/j.ceec.2024.4.14
Abstract:
Introduction In the nuclear power plant, the steam pipeline is generally installed with an insulation layer on the outer wall to improve heat transfer efficiency. Currently, the main detection means for ferromagnetic pipelines are conventional ultrasound and ultrasonic guided waves. Prior to the inspection, the insulation layer on the outer wall of the pipeline needs to be removed, leading to extended inspection time, increased labor costs, and an inability to meet the requirements for high-quality development in nuclear power plants. The application of the pulsed eddy current (PEC) technique for nuclear power plants can eliminate the need for insulation layer removal, enabling non-stop online screening. The defects testing by coil placement is an essential indicator of the PEC technique. Method In this paper, the modeling and simulation of the pipelines was conducted by applying ANSYS Maxwell, coaxial and vertical detection coils were designed respectively to simulate the detection capability of PEC on flat bottom defects with consistency in the lift-off distance, materials and other conditions. Sample pipes were selected from the nuclear power plant for coaxial and vertical PEC testing. The pulsed eddy current testing (PECT) results were cross-validated with ultrasonic thickness measurement, and the effects of two coil placement methods on PECT were compared. Result The results show that vertical coils are more effective in defect detection compared to coaxial coils. Conclusion The defects testing by coil placement has great significance for implementing PEC in the nuclear power sector.
2024, 11(4): 144-155
doi: 10.16516/j.ceec.2024.4.15
Abstract:
Introduction The gas turbine generator set (GE-PG9351FA) with a DLN2.0 + burner and a designed NOx emission concentration of 50 mg/m3 is used in a gas turbine power plant. During the warm-up periods, the generator set emitted a large amount of yellow smoke, which violates provisions stipulated in the "Emission Standard for Air Pollutants from Thermal Power Plants" (GB 13223—2011) and is complained by the surrounding residents. According to the new emission regulations for environmental protection in Jiangsu, starting from January 1, 2023, the converted NOx emission average throughout the operation period should be less than 30 mg/m3. In order to meet this requirement and reduce the emission of yellow nitrate smoke during start-up, the renovated SCR denitration technology for the flue gas of the HRSG (Heat Recovery Steam Generator) is adopted. Data simulation, deduction, analysis and summarization of various indicators are conducted during the start-up process to refine a reasonable startup operation method. Method To validate the feasibility of this method, the power plant conducted multiple peak shaving start-up process operation tests. Based on the actual NOx emission characteristics, adjustments were made to the start-up point, gas turbine load control, and input nodes for the SCR system in the operation method. This process resulted in an optimized operational strategy. Result The test results show that by optimizing the SCR denitration system input point, gas turbine start-up point and warm-up load after grid connection, the converted NOx emission average throughout the operation period is less than 30 mg/m3, and the phenomenon of yellow nitrate smoke disappeared. Conclusion This strategy is based on the characteristics of NOx and yellow nitrate smoke emission during the gas turbine start-up process. Afterward, through data deduction and numerous experiments for validation, it can provide direct guidance for reducing yellow nitrate smoke emission during the start-up process of similar gas turbines. Additionally, it can serve as an analytical reference for controlling NOx emissions during peak shaving operations in gas turbine power plants.
2024, 11(4): 156-163
doi: 10.16516/j.ceec.2024.4.16
Abstract:
Introduction With the development of photovoltaics, energy storage, new building materials and prefabricated construction industry, Building Integrated Photovoltaic (BIPV) technology which features the integrated design and manufacturing of photovoltaic modules with components such as roofs, walls and sunshades is evolving as Building Integrated Photovoltaic and Energy Storage (BIPVES) technology. Method The article proposed the world's first rechargeable cement-based battery, promoting the integration of building walls with photovoltaic power generation and storage and discharging devices. Cross-disciplinary innovation was applied to equipment and materials, where high-definition, high transmittance patterned designs were printed on glass surfaces to manufacture high-efficiency photovoltaic building materials. Prefabricated energy storage walls were developed and integrated with various steel-structure prefabricated building systems to achieve customized production and prefabricated construction, leading to a transformative trend of integrating building components with photovoltaics and energy storage. Result Cement-based batteries allow building walls to have multiple functions, including photovoltaic power generation, energy storage and power supply; The new generation of photovoltaic building materials helps save costs on building facade decoration materials and reduce building carbon emissions; The integration of photovoltaics, energy storage and renewable energy technologies in buildings can achieve maximum benefits. Conclusion The new photovoltaic building materials and new energy storage technologies such as cement-based batteries show promising prospects. Combining and integrating rechargeable battery components, photovoltaic exterior panels, prefabricated building walls and embedded parts for widespread application is feasible.
2024, 11(4): 164-171
doi: 10.16516/j.ceec.2024.4.17
Abstract:
Introduction With the development of "3060" double carbon target, the usage of the PV and wind power for hydrogen gas production is becoming a hot and cutting-edge direction. The combustion of natural gas mixed with hydrogen gas in gas turbine of hydrogen gas industry will become the final step to convert hydrogen into electric power. The gas turbine unit have pressure regulation station, front module and connection pipe. The front module have requirements on the flow rate, pressure, temperature and particle content. And the pressure regulation station will provide the required mixed gas to front module. The connection pipe will have a length of 1 000 m which depended on the different arrangement. The character of pressure drop and temperature drop of connection pipe will have direct impact on the interface parameter of pressure regulation station. So it is necessary to study the character of pressure drop and temperature drop of connection pipe. And it will provide a practicable solution for the future gas turbine fired with natural gas mixed with hydrogen gas. Method The fuel demand was given for the H class gas turbine fired with mixture of natural gas and hydrogen gas after the simulation calculation with GT Pro software. The recommended material selection and velocity selection were presented based on required temperature and pressure drop by H class gas turbine front module and the physical character of mixed gas. The pipe pressure drop and temperature drop due to pressure drop were also calculated. Result The pipe material selection, diameter selection, pipe pressure drop and temperature drop due to pressure drop of pipe are presented. Conclusion For present time, the pipe design between natural gas pressure regulation station and gas turbine front module shall evaluate the material, outer diameter, wall thickness, velocity, pipe resistance, etc., each by each under the condition with hydrogen gas mixture. Thus the gas turbine can use natural gas at present phase and can be shifted to combustion with mixed hydrogen gas smoothly.
2024, 11(4): 172-179
doi: 10.16516/j.ceec.2024.4.18
Abstract:
Introduction This paper explores multiple issues including the voltage application method, test voltage standard, test casing layout, and test item sequence for the handover test of the electrical primary equipment of the world's first 500 kV offshore booster station. Method Based on the test conditions and requirements, a comparison and analysis of the test voltage values and the insulation strength of the equipment were conducted. According to the structural characteristics of GIS and cables, the method of jointly testing GIS and cables was used to apply voltage to the cables. Considering the spatial environment and maximum insulation distance of the offshore booster station, the 500 kV GIS withstand voltage test casing was arranged outside the booster station. By comparing the test voltage values of the test items for 500 kV and 66 kV distribution equipment, the test item sequence was arranged rationally. Result The voltage application method for the withstand voltage test of the medium voltage winding of the main transformer, the voltage standard for the 66 kV GIS test, and the sequence of test items for cables and GIS equipment are determined. The handover tests of transformers, cables, and GIS are completed at the manufacturing base. Conclusion The handover test method for the electrical primary equipment of the world's first 500 kV offshore booster station can be used to simplify the test preparation work and shorten the test period. The method demonstrates certain engineering application value and can be used as references for other offshore booster station projects.
2024, 11(4): 180-189
doi: 10.16516/j.ceec.2024.4.19
Abstract:
Introduction Offshore wind power generation is gradually being widely applied in the global energy structure transformation due to its advantages of high annual power generation and stable power generation. However, due to the complex and ever-changing marine environment for offshore wind turbine construction, this poses significant obstacles to the construction process and technical solutions of offshore wind turbine foundations. Method In the context of the construction project of a certain offshore wind farm, this paper analyzed the type selection criteria and feasibility of pile driving construction ships, pile stabilizing platforms and hydraulic pile hammers. At the same time, in response to the construction requirements for wind turbine foundation pile driving, the preparation work before the operation, the construction plan for the pile stabilizing platform, and the wind turbine foundation pile driving operation with the cooperation of the main-auxiliary crane ships were emphasized. Furthermore, the control and correction measures for verticality in wind turbine foundation pile driving were analyzed. Result Steel pipe pile driving construction process can effectively ensure the project quality and expected progress, and has significant economic benefits, safety and reliability. During the pile driving process, it's necessary to complete preliminary and final adjustments to the verticality accural control. Conclusion Through the study of pile driving construction technology for offshore wind turbine foundations, it will provide useful reference and inspiration for similar offshore wind turbine projects.
