To accurately diagnose the aging condition of the vehicle-mounted high-voltage cable terminals under the combined electro-thermal stress, this paper proposes a terahertz frequency spectrum technology-based method. First, an electro-thermal aging platform is established in the laboratory to obtain the test samples of ethylene-propylene rubber (EPR) cable terminals with different aging gradients. Then, the degree of electro-thermal aging is characterized by frequency spectrum, absorption coefficient spectrum, absorption spectrum, refractive index and dielectric constant in the terahertz domain. Moreover, the micro-morphology and micro-area structure of the test samples under different aging gradients are also observed by scanning electron microscopy, and both the material and chemical properties are analyzed. The findings demonstrate that terahertz frequency spectra offer significant benefits in non-destructively detecting and identifying the insulation condition of vehicle cable terminals during electro-thermal aging. Laboratory tests confirm the feasibility of utilizing the terahertz frequency spectrum to assess the insulation aging state of EPR cable terminals, making it potentially applicable for on-site purposes.
{"title":"Terahertz Frequency Domain Response for Insulation State Assessment of Vehicle Cable Terminal Under Electro-Thermal Aging","authors":"Binglei Cao;Shuaibing Li;Yi Cui;Dong Yang;Yongqiang Kang;Baopeng Lu;Guangning Wu","doi":"10.17775/CSEEJPES.2023.02300","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2023.02300","url":null,"abstract":"To accurately diagnose the aging condition of the vehicle-mounted high-voltage cable terminals under the combined electro-thermal stress, this paper proposes a terahertz frequency spectrum technology-based method. First, an electro-thermal aging platform is established in the laboratory to obtain the test samples of ethylene-propylene rubber (EPR) cable terminals with different aging gradients. Then, the degree of electro-thermal aging is characterized by frequency spectrum, absorption coefficient spectrum, absorption spectrum, refractive index and dielectric constant in the terahertz domain. Moreover, the micro-morphology and micro-area structure of the test samples under different aging gradients are also observed by scanning electron microscopy, and both the material and chemical properties are analyzed. The findings demonstrate that terahertz frequency spectra offer significant benefits in non-destructively detecting and identifying the insulation condition of vehicle cable terminals during electro-thermal aging. Laboratory tests confirm the feasibility of utilizing the terahertz frequency spectrum to assess the insulation aging state of EPR cable terminals, making it potentially applicable for on-site purposes.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"11 1","pages":"458-467"},"PeriodicalIF":6.9,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10520190","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The implementation of modular multilevel converters (MMC) in an electric ship to create a medium voltage direct current (MVDC) energy conversion system that is efficient, small, dependable, and easily scalable has garnered considerable interest. In this research, an improved two-step nearest level control (E-NLC) is presented for MMC with a three-level submodule (3L-SM) as the rectifier of the electric ship power generation units in order to ease the economical and reliable operation of MMCs in MVDC systems. To achieve DC fault-clearing capability, the use of MMC with 3L-SM minimizes the number of switching devices when compared to the regular MMC topology. The suggested E-NLC scheme aims to reduce total harmonic distortion (THD) and achieve the nearest zero common mode voltage (CMV). The output voltage vector of the three phases is tuned using eight candidate vectors capable of suppressing CMV rather than the nearest-level vector, and the rounding function is modified to improve harmonic performance by increasing the approximation between stepped and modulated waves. The generator-connected MMC with THD reduction and CMV elimination maximizes the mover's protection in the generating unit of the electric ship's MVDC system. Simulation and experiment results validate the efficacy of the suggested approach with respect to steady-state and dynamic-state performance.
{"title":"Enhanced Two-Step Nearest Level Control with Enhanced Power Quality for Electric Ship System","authors":"Hui Hwang Goh;Jiaru Sun;Xue Liang;Dongdong Zhang;Wei Dai;Shaojian Song;Tonni Agustiono Kurniawan;Kai Chen Goh","doi":"10.17775/CSEEJPES.2023.00740","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2023.00740","url":null,"abstract":"The implementation of modular multilevel converters (MMC) in an electric ship to create a medium voltage direct current (MVDC) energy conversion system that is efficient, small, dependable, and easily scalable has garnered considerable interest. In this research, an improved two-step nearest level control (E-NLC) is presented for MMC with a three-level submodule (3L-SM) as the rectifier of the electric ship power generation units in order to ease the economical and reliable operation of MMCs in MVDC systems. To achieve DC fault-clearing capability, the use of MMC with 3L-SM minimizes the number of switching devices when compared to the regular MMC topology. The suggested E-NLC scheme aims to reduce total harmonic distortion (THD) and achieve the nearest zero common mode voltage (CMV). The output voltage vector of the three phases is tuned using eight candidate vectors capable of suppressing CMV rather than the nearest-level vector, and the rounding function is modified to improve harmonic performance by increasing the approximation between stepped and modulated waves. The generator-connected MMC with THD reduction and CMV elimination maximizes the mover's protection in the generating unit of the electric ship's MVDC system. Simulation and experiment results validate the efficacy of the suggested approach with respect to steady-state and dynamic-state performance.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"11 4","pages":"1670-1680"},"PeriodicalIF":5.9,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10520188","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-03DOI: 10.17775/CSEEJPES.2023.04990
Feng Hong;Yalei Pang;Weiming Ji;Lu Liang;Fang Fang;Junhong Hao;Jizhen Liu
Frequency stability and security have been a vital challenge as large-scale renewable energy is integrated into power systems. In contrast, the proportion of traditional thermal power units decreases during the decarbonization transformation process, resulting in poor frequency support. This paper aims to explore the potential of frequency regulation support, dynamic assessment, and capacity promotion of thermal power plants in the transition period. Considering the dynamic characteristics of the main steam working fluid under different working conditions, a nonlinear observer is constructed by extracting the main steam pressure and valve opening degree parameters. The real-time frequency modulation capacity of thermal power units can provide a dynamic state for the power grid. A dynamic adaptive modification for primary frequency control (PFC) of power systems, including wind power and thermal power, is proposed and improved. The power dynamic allocation factor is adaptively optimized by predicting the speed droop ratio, and the frequency modulation capability of the system is improved by more than 11% under extreme conditions. Finally, through the Monte Carlo simulation of unit states of the system under various working conditions, the promotion of the frequency regulation capacity with high wind power penetration (WPP) is verified.
{"title":"Assessment and Enhancement of FRC of Power Systems Considering Thermal Power Dynamic Conditions","authors":"Feng Hong;Yalei Pang;Weiming Ji;Lu Liang;Fang Fang;Junhong Hao;Jizhen Liu","doi":"10.17775/CSEEJPES.2023.04990","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2023.04990","url":null,"abstract":"Frequency stability and security have been a vital challenge as large-scale renewable energy is integrated into power systems. In contrast, the proportion of traditional thermal power units decreases during the decarbonization transformation process, resulting in poor frequency support. This paper aims to explore the potential of frequency regulation support, dynamic assessment, and capacity promotion of thermal power plants in the transition period. Considering the dynamic characteristics of the main steam working fluid under different working conditions, a nonlinear observer is constructed by extracting the main steam pressure and valve opening degree parameters. The real-time frequency modulation capacity of thermal power units can provide a dynamic state for the power grid. A dynamic adaptive modification for primary frequency control (PFC) of power systems, including wind power and thermal power, is proposed and improved. The power dynamic allocation factor is adaptively optimized by predicting the speed droop ratio, and the frequency modulation capability of the system is improved by more than 11% under extreme conditions. Finally, through the Monte Carlo simulation of unit states of the system under various working conditions, the promotion of the frequency regulation capacity with high wind power penetration (WPP) is verified.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"10 4","pages":"1371-1383"},"PeriodicalIF":6.9,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10520152","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141966166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Composite insulators have been widely used in transmission lines. After being removed from transmission lines, their housing silicone material cannot degrade naturally. To tackle this problem, this paper proposes an effective method to recycle waste insulators by pyrolysis to obtain mullite $(mathbf{3}mathbf{Al}_{2}mathbf{O}_{3}cdot mathbf{2}mathbf{SiO}_{2})$ with high purity and compact structure. The recycling process studied will not generate toxic products. The thermal degradation process of housing material is investigated by analyzing its degradation products including the gas and residues in detail. The experimental results indicate that the colorant agent Fe 2 O 3 inside the housing material is beneficial for the generation of mullite by decreasing the temperature of mullitization. Besides, since the transitional alumina generated by the dehydration of aluminum hydroxide (ATH) has a smaller diameter and can better dissolute into the silica phases, ATH is a better choice as the additional aluminum resource. By comparing the components, structure, and particle size of grains formed at different calcination temperatures, the proposed pyrolysis temperatures of the two stages are 1400°C and 1600°C, respectively.
复合绝缘子已广泛应用于输电线路。从输电线路上拆除后，其外壳硅胶材料无法自然降解。针对这一问题，本文提出了一种通过热解回收废绝缘子的有效方法，从而获得纯度高、结构紧凑的莫来石 $(mathbf{3}mathbf{Al}_{2}mathbf{O}_{3}cdot mathbf{2}mathbf{SiO}_{2})$。所研究的回收过程不会产生有毒产品。通过详细分析其降解产物（包括气体和残留物），研究了住房材料的热降解过程。实验结果表明，外壳材料中的着色剂 Fe2O3 可降低莫来石化温度，有利于莫来石的生成。此外，由于氢氧化铝（ATH）脱水生成的过渡氧化铝直径较小，能更好地溶解到二氧化硅相中，因此 ATH 是作为附加铝资源的更好选择。通过比较不同煅烧温度下形成的颗粒的成分、结构和粒度，建议两个阶段的热解温度分别为 1400°C 和 1600°C。
{"title":"Recycling of Silicone Rubber from Composite Insulator with Pyrolysis Method","authors":"Ruiqi Shang;Liming Wang;Fanghui Yin;Masoud Farzaneh","doi":"10.17775/CSEEJPES.2022.05800","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2022.05800","url":null,"abstract":"Composite insulators have been widely used in transmission lines. After being removed from transmission lines, their housing silicone material cannot degrade naturally. To tackle this problem, this paper proposes an effective method to recycle waste insulators by pyrolysis to obtain mullite \u0000<tex>$(mathbf{3}mathbf{Al}_{2}mathbf{O}_{3}cdot mathbf{2}mathbf{SiO}_{2})$</tex>\u0000 with high purity and compact structure. The recycling process studied will not generate toxic products. The thermal degradation process of housing material is investigated by analyzing its degradation products including the gas and residues in detail. The experimental results indicate that the colorant agent Fe\u0000<inf>2</inf>\u0000O\u0000<inf>3</inf>\u0000 inside the housing material is beneficial for the generation of mullite by decreasing the temperature of mullitization. Besides, since the transitional alumina generated by the dehydration of aluminum hydroxide (ATH) has a smaller diameter and can better dissolute into the silica phases, ATH is a better choice as the additional aluminum resource. By comparing the components, structure, and particle size of grains formed at different calcination temperatures, the proposed pyrolysis temperatures of the two stages are 1400°C and 1600°C, respectively.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"10 4","pages":"1787-1798"},"PeriodicalIF":6.9,"publicationDate":"2024-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10520158","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141966281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Under the “dual carbon” goals, it is imperative to incorporate carbon emissions-related factors into research of power grid risk assessment to meet the green transformation needs of the power grid. Therefore, this paper conducts a study on the risk assessment of carbon emissions changes in regional power grids based on dynamic carbon emission factors, aiming to quantitatively analyze the impact of random disturbances such as equipment failures or fluctuations in renewable energy generation on the carbon emission intensity of regional power grids. First, carbon emission change risk indicators are constructed from three dimensions: the probability, frequency, and magnitude of carbon emission changes. Second, a dynamic carbon emission factor calculation model is proposed to reflect the spatiotemporal change of carbon emissions in the regional power grid, considering output of different types of generators and the components of inter-area power transmission. Finally, with the premise of ensuring safe and stable operation of power grid, a quantitative assessment model for carbon emission change risks is proposed under the objective of minimizing the electricity loss. The sampling convergence conditions of the model are also derived. The results from the MRTS79 case study demonstrate the proposed method can effectively quantify and analyze the risk of carbon emissions changes in regional power grids, validating the effectiveness of the proposed model.
{"title":"Regional Power Grid Carbon Emission Change Risk Assessment Based on Dynamic Carbon Emission Factors","authors":"Huiyuan Yang;Aihong Tang;Kanjun Zhang;Ting Wang;Hubing Zhou;Xinran Li;Hengxuan Li;Wenhao Wang;Jiao Peng","doi":"10.17775/CSEEJPES.2023.03280","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2023.03280","url":null,"abstract":"Under the “dual carbon” goals, it is imperative to incorporate carbon emissions-related factors into research of power grid risk assessment to meet the green transformation needs of the power grid. Therefore, this paper conducts a study on the risk assessment of carbon emissions changes in regional power grids based on dynamic carbon emission factors, aiming to quantitatively analyze the impact of random disturbances such as equipment failures or fluctuations in renewable energy generation on the carbon emission intensity of regional power grids. First, carbon emission change risk indicators are constructed from three dimensions: the probability, frequency, and magnitude of carbon emission changes. Second, a dynamic carbon emission factor calculation model is proposed to reflect the spatiotemporal change of carbon emissions in the regional power grid, considering output of different types of generators and the components of inter-area power transmission. Finally, with the premise of ensuring safe and stable operation of power grid, a quantitative assessment model for carbon emission change risks is proposed under the objective of minimizing the electricity loss. The sampling convergence conditions of the model are also derived. The results from the MRTS79 case study demonstrate the proposed method can effectively quantify and analyze the risk of carbon emissions changes in regional power grids, validating the effectiveness of the proposed model.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"12 1","pages":"437-447"},"PeriodicalIF":5.9,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10452329","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, we propose a two-stage transmission hardening and planning (TH&P) model that can meet the load growth demand of normal scenarios and the resilience requirements of hurricane-induced damage scenarios. To better measure the resilience requirements, the proposed TH&P model includes two resilience assessment indexes, namely, the load shedding (LS) under the damage scenario and the average connectivity degree (ACD) at different stages. The first-stage model, which aims to meet the load growth demand while minimizing the LS, is formulated as a mixed-integer linear program (MILP) to minimize the total planning and hardening cost of transmission lines, the operating cost of generators, and the penalty cost of wind power and load shedding in both normal and damage scenarios. The second-stage model aims to further improve the ACD when the ACD of the scheme obtained from the first-stage model cannot reach the target. Specifically, the contribution of each transmission line to the ACD is calculated, and the next hardened line is determined to increase the ACD. This process is repeated until the ACD meets the requirements. Case studies of the modified IEEE RTS-24 and two-area IEEE reliability test system-1996 indicate the proposed TH&P model can meet the requirements for both normal and damage scenarios.
{"title":"Resilience-oriented Hardening and Expansion Planning of Transmission System Under Hurricane Impact","authors":"Jing Zhou;Heng Zhang;Haozhong Cheng;Shenxi Zhang;Lu Liu;Zheng Wang;Xiaohu Zhang","doi":"10.17775/CSEEJPES.2022.07300","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2022.07300","url":null,"abstract":"In this paper, we propose a two-stage transmission hardening and planning (TH&P) model that can meet the load growth demand of normal scenarios and the resilience requirements of hurricane-induced damage scenarios. To better measure the resilience requirements, the proposed TH&P model includes two resilience assessment indexes, namely, the load shedding (LS) under the damage scenario and the average connectivity degree (ACD) at different stages. The first-stage model, which aims to meet the load growth demand while minimizing the LS, is formulated as a mixed-integer linear program (MILP) to minimize the total planning and hardening cost of transmission lines, the operating cost of generators, and the penalty cost of wind power and load shedding in both normal and damage scenarios. The second-stage model aims to further improve the ACD when the ACD of the scheme obtained from the first-stage model cannot reach the target. Specifically, the contribution of each transmission line to the ACD is calculated, and the next hardened line is determined to increase the ACD. This process is repeated until the ACD meets the requirements. Case studies of the modified IEEE RTS-24 and two-area IEEE reliability test system-1996 indicate the proposed TH&P model can meet the requirements for both normal and damage scenarios.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"10 4","pages":"1746-1760"},"PeriodicalIF":6.9,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10452306","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141966283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-27DOI: 10.17775/CSEEJPES.2022.05090
Zekai Wang;Tao Ding;Xiaosheng Zhang;Chenggang Mu;Pengwei Du;Fangxing Li
This paper proposes a voltage source converter (VSC) -based AC-DC hybrid distribution system (HDS) resilient model to mitigate power outages caused by wildfires. Before a wildfire happens, the public-safety power shutoff (PSPS) strategy is applied to actively cut some vulnerable lines which may easily cause wildfires, and reinforce some lines that are connected to critical loads. To mitigate load shedding caused by active line disconnection in the PSPS strategy, network reconfiguration is applied before the wildfire occurrence. During the restoration period, repair crews (RCs) repair faulted lines, and network reconfiguration is also taken into consideration in the recovery strategy to pick up critical loads. Since there exists possible errors in the wildfire prediction, several different scenarios of wildfire occurrence have been taken into consideration, leading to the proposition of a stochastic multi-period resilient model for the VSC-based AC-DC HDS. To accelerate the computational performance, a progressive hedging algorithm has been applied to solve the stochastic model which can be written as a mixed-integer linear program. The proposed model is verified on a 106-bus AC-DC HDS under wildfire conditions, and the result shows the proposed model not only can improve the system resilience but also accelerate computational speed.
{"title":"Multi-Period Resilient Model for VSC-Based AC-DC HDS Considering Public-Safety Power Shutoff to Mitigate Wildfires","authors":"Zekai Wang;Tao Ding;Xiaosheng Zhang;Chenggang Mu;Pengwei Du;Fangxing Li","doi":"10.17775/CSEEJPES.2022.05090","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2022.05090","url":null,"abstract":"This paper proposes a voltage source converter (VSC) -based AC-DC hybrid distribution system (HDS) resilient model to mitigate power outages caused by wildfires. Before a wildfire happens, the public-safety power shutoff (PSPS) strategy is applied to actively cut some vulnerable lines which may easily cause wildfires, and reinforce some lines that are connected to critical loads. To mitigate load shedding caused by active line disconnection in the PSPS strategy, network reconfiguration is applied before the wildfire occurrence. During the restoration period, repair crews (RCs) repair faulted lines, and network reconfiguration is also taken into consideration in the recovery strategy to pick up critical loads. Since there exists possible errors in the wildfire prediction, several different scenarios of wildfire occurrence have been taken into consideration, leading to the proposition of a stochastic multi-period resilient model for the VSC-based AC-DC HDS. To accelerate the computational performance, a progressive hedging algorithm has been applied to solve the stochastic model which can be written as a mixed-integer linear program. The proposed model is verified on a 106-bus AC-DC HDS under wildfire conditions, and the result shows the proposed model not only can improve the system resilience but also accelerate computational speed.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"10 2","pages":"821-833"},"PeriodicalIF":7.1,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10452302","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140351540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-27DOI: 10.17775/CSEEJPES.2022.07090
Le Sun;Zhaoguo Liu;Xiaoqiang Guo;Xiaochen Wang;Lichong Wang
A multi-phase stacked interleaved buck converter (SIBC) is suitable for large-power water electrolysis applications due to its merits of high current output capability and zero output current ripple. However, the auxiliary converter used to compensate for the current ripple still has to withstand high voltage stress. This paper proposes a new multi-phase SIBC applied in the multicarrier energy system integrating electricity, heat, and hydrogen. A resistor-capacitor voltage divider is used to provide the input voltage of the auxiliary converter and as a heater for the thermal loads. Thus, the voltage stress of the auxiliary converter can be reduced at a low cost, and the size of the filter inductor can be reduced. With accurate voltage and current analysis and appropriate parameter design, the voltage stresses of both the switches and capacitors in the auxiliary converter can be further limited within an expected range. The experimental results verify the correctness of the topology, modulation, analysis, and design methods. A comparison with the conventional method is made in terms of cost, volume, and efficiency to show the advantages of the proposed method.
{"title":"Multi-Phase Stacked Interleaved Buck Converter for Hydrogen-Production Electrolysis with Low-Voltage-Stress Ripple Compensation Circuit","authors":"Le Sun;Zhaoguo Liu;Xiaoqiang Guo;Xiaochen Wang;Lichong Wang","doi":"10.17775/CSEEJPES.2022.07090","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2022.07090","url":null,"abstract":"A multi-phase stacked interleaved buck converter (SIBC) is suitable for large-power water electrolysis applications due to its merits of high current output capability and zero output current ripple. However, the auxiliary converter used to compensate for the current ripple still has to withstand high voltage stress. This paper proposes a new multi-phase SIBC applied in the multicarrier energy system integrating electricity, heat, and hydrogen. A resistor-capacitor voltage divider is used to provide the input voltage of the auxiliary converter and as a heater for the thermal loads. Thus, the voltage stress of the auxiliary converter can be reduced at a low cost, and the size of the filter inductor can be reduced. With accurate voltage and current analysis and appropriate parameter design, the voltage stresses of both the switches and capacitors in the auxiliary converter can be further limited within an expected range. The experimental results verify the correctness of the topology, modulation, analysis, and design methods. A comparison with the conventional method is made in terms of cost, volume, and efficiency to show the advantages of the proposed method.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"12 1","pages":"401-410"},"PeriodicalIF":5.9,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10452305","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bipolar blocking and commutation failure in the renewable energy transmission system through ultra-high voltage direct current will produce significant temporary overvoltage. This paper analyzes the physical process of sending end grid overvoltage caused by two types of DC faults and establishes a DC overvoltage model considering renewable energy sources. According to characteristics of the sending end grid, the influence of the system equivalent impedance, the proportion of renewable energy output, the active and reactive power coefficients of the renewable energy sources during the low voltage ride through process on the overvoltage is analyzed respectively, and the relationship between the proportion of renewable energy output and the short-circuit ratio under the overvoltage constraint is constructed. The validity and practicality of the model and analysis method proposed in this paper are verified by combining the typical transmission system at the sending end of the actual power grid and regional power grid systems.
{"title":"Overvoltage Calculation Method for Sending System Under DC Fault Disturbance Considering the Influence of Renewable Energy","authors":"Haoyue Gong;Jianbo Guo;Qiang Guo;Jian Zhang;Qinyong Zhou;Libo Zhang","doi":"10.17775/CSEEJPES.2023.00290","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2023.00290","url":null,"abstract":"Bipolar blocking and commutation failure in the renewable energy transmission system through ultra-high voltage direct current will produce significant temporary overvoltage. This paper analyzes the physical process of sending end grid overvoltage caused by two types of DC faults and establishes a DC overvoltage model considering renewable energy sources. According to characteristics of the sending end grid, the influence of the system equivalent impedance, the proportion of renewable energy output, the active and reactive power coefficients of the renewable energy sources during the low voltage ride through process on the overvoltage is analyzed respectively, and the relationship between the proportion of renewable energy output and the short-circuit ratio under the overvoltage constraint is constructed. The validity and practicality of the model and analysis method proposed in this paper are verified by combining the typical transmission system at the sending end of the actual power grid and regional power grid systems.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"10 5","pages":"1865-1875"},"PeriodicalIF":6.9,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10452328","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142397518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-14DOI: 10.17775/CSEEJPES.2022.08160
Jianzhong Xu;Conghui Zheng;Wanying Xu;Moke Feng;Chengyong Zhao;Gen Li
Due to the advanced features of multidirectional power transfer and fast smoothing of the power fluctuation in renewable energy systems, the multiple-active-bridge based power-electronic-transformer (MAB-PET) with integrated energy storage units is becoming popular. However, the accurate electromagnetic transient simulation of the MAB-PETs is extremely time-consuming due to the large number of circuit nodes and small time-step. This paper proposes a simplified EMT modeling approach for the MAB-PETs by employing the generalized state-space averaging method. First, the switching function method and Dommel algorithm are used to build the equivalent model of each power module. Further, the PET equivalent model is presented in a multi-port PM polymerization mode. The system is simplified by applying Fourier Decomposition to its state functions by ignoring high-order harmonics. Finally, a four-port equivalent voltage source circuit is obtained. The proposed simplified equivalent model is compared with the detailed model in PSCAD/EMTDC. Simulation results show the proposed approach has excellent accuracy and is 2–3 orders of magnitude faster than the DM.
{"title":"Simplified EMT Model of Multiple-Active-Bridge Based Power Electronic Transformer with Integrated Energy Storage","authors":"Jianzhong Xu;Conghui Zheng;Wanying Xu;Moke Feng;Chengyong Zhao;Gen Li","doi":"10.17775/CSEEJPES.2022.08160","DOIUrl":"https://doi.org/10.17775/CSEEJPES.2022.08160","url":null,"abstract":"Due to the advanced features of multidirectional power transfer and fast smoothing of the power fluctuation in renewable energy systems, the multiple-active-bridge based power-electronic-transformer (MAB-PET) with integrated energy storage units is becoming popular. However, the accurate electromagnetic transient simulation of the MAB-PETs is extremely time-consuming due to the large number of circuit nodes and small time-step. This paper proposes a simplified EMT modeling approach for the MAB-PETs by employing the generalized state-space averaging method. First, the switching function method and Dommel algorithm are used to build the equivalent model of each power module. Further, the PET equivalent model is presented in a multi-port PM polymerization mode. The system is simplified by applying Fourier Decomposition to its state functions by ignoring high-order harmonics. Finally, a four-port equivalent voltage source circuit is obtained. The proposed simplified equivalent model is compared with the detailed model in PSCAD/EMTDC. Simulation results show the proposed approach has excellent accuracy and is 2–3 orders of magnitude faster than the DM.","PeriodicalId":10729,"journal":{"name":"CSEE Journal of Power and Energy Systems","volume":"11 3","pages":"1199-1210"},"PeriodicalIF":6.9,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10436589","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144243645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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