Reliable protections are the guarantee of the safe and stable operation of HVDC system. In order to avoid the mal-operation of the transmission line protection in HVDC system due to the lightning stroke disturbance, this paper studies the different characteristics of lightning disturbance and fault, and proposes a voltage deviation based lightning stroke identification method. The voltage deviation of positive pole is utilised to distinguish lightning disturbance from lightning fault, and the voltage deviation of negative pole is utilised to identify the fault type. Extensive simulation results show that the proposed lightning stroke identification method can distinguish disturbances form faults and judge the fault type correctly.
{"title":"A novel identification method of lightning strokes for hvdc transmission lines based on voltage deviation","authors":"Y. Wang, W. Mo, D. Zheng","doi":"10.1049/icp.2021.2535","DOIUrl":"https://doi.org/10.1049/icp.2021.2535","url":null,"abstract":"Reliable protections are the guarantee of the safe and stable operation of HVDC system. In order to avoid the mal-operation of the transmission line protection in HVDC system due to the lightning stroke disturbance, this paper studies the different characteristics of lightning disturbance and fault, and proposes a voltage deviation based lightning stroke identification method. The voltage deviation of positive pole is utilised to distinguish lightning disturbance from lightning fault, and the voltage deviation of negative pole is utilised to identify the fault type. Extensive simulation results show that the proposed lightning stroke identification method can distinguish disturbances form faults and judge the fault type correctly.","PeriodicalId":242596,"journal":{"name":"2021 Annual Meeting of CSEE Study Committee of HVDC and Power Electronics (HVDC 2021)","volume":" 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113949745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Wu, L. Hao, S. Pan, J. Gong, X. Dang, Yanlin Zhou
Wind power generation is one of the most mature and scale of developing new energy generation technology. Using advanced transmission technology to realize future offshore wind power base transmission has become an important direction under the background of future power grid construction and new infrastructure construction. The DC transmission method is mature in technology, but the converter station occupies a large area, and the platform is expensive. This paper proposes a modular converter topology suitable for offshore wind power generation with a minimum decoupling capacitor. The four-port LLCDCX is used as the key component of ripple cancellation, which can eliminate double-frequency power ripple, significantly reduce the volume of the converter and increase the power density. The inverter unit adopts the cascaded H-bridge structure and can be combined to meet the requirements of different levels of occasions. The DC side power decoupling control strategy is proposed, and the simulation results show the accuracy of the control strategy. The proposed topology provides new ideas for the construction of offshore wind power DC grids.
{"title":"A modular converter topology for offshore wind power generation with minimum decoupling capacitor","authors":"Y. Wu, L. Hao, S. Pan, J. Gong, X. Dang, Yanlin Zhou","doi":"10.1049/icp.2021.2575","DOIUrl":"https://doi.org/10.1049/icp.2021.2575","url":null,"abstract":"Wind power generation is one of the most mature and scale of developing new energy generation technology. Using advanced transmission technology to realize future offshore wind power base transmission has become an important direction under the background of future power grid construction and new infrastructure construction. The DC transmission method is mature in technology, but the converter station occupies a large area, and the platform is expensive. This paper proposes a modular converter topology suitable for offshore wind power generation with a minimum decoupling capacitor. The four-port LLCDCX is used as the key component of ripple cancellation, which can eliminate double-frequency power ripple, significantly reduce the volume of the converter and increase the power density. The inverter unit adopts the cascaded H-bridge structure and can be combined to meet the requirements of different levels of occasions. The DC side power decoupling control strategy is proposed, and the simulation results show the accuracy of the control strategy. The proposed topology provides new ideas for the construction of offshore wind power DC grids.","PeriodicalId":242596,"journal":{"name":"2021 Annual Meeting of CSEE Study Committee of HVDC and Power Electronics (HVDC 2021)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133726182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Full Bridge Modular Multilevel Converter (FBMMC) is suitable for DC short-circuit fault ride-through in high voltage direct current (HVDC) transmission due to its characteristic of outputting negative level. This paper establishes a theoretical mathematical model for the DC component and AC component of the MMC bridge, and then proposes an AC-DC decoupling control strategy that can quickly achieve fault ride-through. This strategy separately controls the AC component and DC voltage of the bridge voltage by constructing an intermediate voltage, effectively avoiding the influence of DC faults on the AC component. The voltage fluctuation of the sub-module changes during the fault ride-through process. This paper derives its fluctuation characteristics from the perspective of energy fluctuations. Finally, a corresponding simulation was built in the RTLAB real-time simulation platform to verify the correctness and effectiveness of the strategy and the fluctuation of the fault process sub-module.
{"title":"AC / DC decoupling control strategy for DC short circuit fault ride through of full bridge MMC","authors":"H. Zhao, L. Jing, Y. Wei, X. Wu, S. Wang, R. Tian","doi":"10.1049/icp.2021.2545","DOIUrl":"https://doi.org/10.1049/icp.2021.2545","url":null,"abstract":"Full Bridge Modular Multilevel Converter (FBMMC) is suitable for DC short-circuit fault ride-through in high voltage direct current (HVDC) transmission due to its characteristic of outputting negative level. This paper establishes a theoretical mathematical model for the DC component and AC component of the MMC bridge, and then proposes an AC-DC decoupling control strategy that can quickly achieve fault ride-through. This strategy separately controls the AC component and DC voltage of the bridge voltage by constructing an intermediate voltage, effectively avoiding the influence of DC faults on the AC component. The voltage fluctuation of the sub-module changes during the fault ride-through process. This paper derives its fluctuation characteristics from the perspective of energy fluctuations. Finally, a corresponding simulation was built in the RTLAB real-time simulation platform to verify the correctness and effectiveness of the strategy and the fluctuation of the fault process sub-module.","PeriodicalId":242596,"journal":{"name":"2021 Annual Meeting of CSEE Study Committee of HVDC and Power Electronics (HVDC 2021)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133389938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Based on two concrete cases of abnormal warning of 500kV circuit breaker protection and 220kV line protection device arising from hardware fault, troubleshooting was carried out based on relevant experimental and inspection data in aspects of the device logic, principle and secondary loop, and finally reasons of these two abnormalities were found, and the analytical conclusions were drawn.
{"title":"Analysis on abnormal service conditions of the switch quantity of the microcomputer protection device","authors":"X. Wu, H. Cong, H. Chengxi","doi":"10.1049/icp.2021.2543","DOIUrl":"https://doi.org/10.1049/icp.2021.2543","url":null,"abstract":"Based on two concrete cases of abnormal warning of 500kV circuit breaker protection and 220kV line protection device arising from hardware fault, troubleshooting was carried out based on relevant experimental and inspection data in aspects of the device logic, principle and secondary loop, and finally reasons of these two abnormalities were found, and the analytical conclusions were drawn.","PeriodicalId":242596,"journal":{"name":"2021 Annual Meeting of CSEE Study Committee of HVDC and Power Electronics (HVDC 2021)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132711178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a root clause failure analysis of laminated glass fiber reinforced plastic (GFRP) composite tubes after hydrostatic experiment was performed to find out the effect of microstructure defects on the residual strain of the tubes after unloading. The analysis consisted of three steps: Firstly, microscopic images of failed areas of the GFRP tubes were obtained to analyse the dominated microstructure defects leading to the failure as well as the possible failure mechanisms. Then, a computational finite element model considering the microstructure defects was established to predict the failure initiation pressure and location of the laminated GFRP tubes by incorporating the Tsai-Hill failure criteria. Finally, the recommended ply design and defect size range were calculated by the computational model to improve the hydrostatic mechanical properties of the laminated GFRP composite tubes. The results demonstrated that fiber waviness was a critical factor which would cause the early failure initiation of the laminated GFRP composite tubes even under very low hydrostatic stress. By utilizing the developed computational models, we can improve the mechanical properties of the composite tubes by optimizing the thickness of each ply and controlling the fiber waviness under specific range.
{"title":"Failure analysis of laminated GFRP composite tubes under hydrostatic stress","authors":"X. Zhang, Z. Chen, Q. Gu, G. Ni, C. Liu","doi":"10.1049/icp.2021.2577","DOIUrl":"https://doi.org/10.1049/icp.2021.2577","url":null,"abstract":"In this paper, a root clause failure analysis of laminated glass fiber reinforced plastic (GFRP) composite tubes after hydrostatic experiment was performed to find out the effect of microstructure defects on the residual strain of the tubes after unloading. The analysis consisted of three steps: Firstly, microscopic images of failed areas of the GFRP tubes were obtained to analyse the dominated microstructure defects leading to the failure as well as the possible failure mechanisms. Then, a computational finite element model considering the microstructure defects was established to predict the failure initiation pressure and location of the laminated GFRP tubes by incorporating the Tsai-Hill failure criteria. Finally, the recommended ply design and defect size range were calculated by the computational model to improve the hydrostatic mechanical properties of the laminated GFRP composite tubes. The results demonstrated that fiber waviness was a critical factor which would cause the early failure initiation of the laminated GFRP composite tubes even under very low hydrostatic stress. By utilizing the developed computational models, we can improve the mechanical properties of the composite tubes by optimizing the thickness of each ply and controlling the fiber waviness under specific range.","PeriodicalId":242596,"journal":{"name":"2021 Annual Meeting of CSEE Study Committee of HVDC and Power Electronics (HVDC 2021)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123008949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Several typical transformer design methods are introduced first, and their main characteristics and applications are compared and analysed. On this basis, an optimal design scheme of solid insulation multi-winding high frequency transformer is proposed. The influence of insulation distance on the structure is fully considered in the proposed scheme, and the additional copper loss caused by skin effect and proximity effect at high frequency is calculated in detail. Therefore, the transformer design can determine the appropriate structure according to the insulation requirements, and also meet the requirements of high efficiency high power density targets. This paper introduces the process of transformer optimization design in detail, analyses the analytical algorithm of transformer design under certain constraints, and gives some basic conclusions of transformer design under different capacities through data and finite element simulation. Finally, combined with experiments, the effectiveness of this design scheme is verified.
{"title":"Optimization design of solid insulation multi-winding high frequency transformer","authors":"J. Yang, Z. Liang, R. Li","doi":"10.1049/icp.2021.2587","DOIUrl":"https://doi.org/10.1049/icp.2021.2587","url":null,"abstract":"Several typical transformer design methods are introduced first, and their main characteristics and applications are compared and analysed. On this basis, an optimal design scheme of solid insulation multi-winding high frequency transformer is proposed. The influence of insulation distance on the structure is fully considered in the proposed scheme, and the additional copper loss caused by skin effect and proximity effect at high frequency is calculated in detail. Therefore, the transformer design can determine the appropriate structure according to the insulation requirements, and also meet the requirements of high efficiency high power density targets. This paper introduces the process of transformer optimization design in detail, analyses the analytical algorithm of transformer design under certain constraints, and gives some basic conclusions of transformer design under different capacities through data and finite element simulation. Finally, combined with experiments, the effectiveness of this design scheme is verified.","PeriodicalId":242596,"journal":{"name":"2021 Annual Meeting of CSEE Study Committee of HVDC and Power Electronics (HVDC 2021)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128094815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Zeng, F. Shen, Y. Chen, M. Liu, F. Chen, X. Pan, P. Zou
As the important part of the high-power semiconductor IGCT, the gate unit which is named GU, controls the turn-on and turnoff actions of GCT. For the GU, the cathode current commutation relies on the energy stored in the turn-off capacitor stack to realize current transfer. At the same time, the forward voltage of the turn-off circuit can't be lower than the reverse voltage generated by the parasitic parameters. Therefore, the capacitance and voltage of the turn-off capacitors need to meet the maximum current of IGCT. The turn-off capacitor stack usually uses the aluminum electrolytic capacitor, which includes the disadvantages of large size, low life, and temperature limit. In order to reduce the volume and increase the life of the product, and also ensure the reliable of the turn-off process. This paper researches and explains the principle of the turn-off energy regenerative or dynamic adjustment topology, and analyzes the control strategy of the high-voltage turn-off topology, then the prototype test verifies that the topology obtains the same turn-off ability under the same current, but it can greatly reduces the capacity of the turnoff capacitors. And it can guarantee the dynamic and static characteristics of the turn-off process.
{"title":"Research on high voltage turn-off topology of IGCT gate unit","authors":"H. Zeng, F. Shen, Y. Chen, M. Liu, F. Chen, X. Pan, P. Zou","doi":"10.1049/icp.2021.2554","DOIUrl":"https://doi.org/10.1049/icp.2021.2554","url":null,"abstract":"As the important part of the high-power semiconductor IGCT, the gate unit which is named GU, controls the turn-on and turnoff actions of GCT. For the GU, the cathode current commutation relies on the energy stored in the turn-off capacitor stack to realize current transfer. At the same time, the forward voltage of the turn-off circuit can't be lower than the reverse voltage generated by the parasitic parameters. Therefore, the capacitance and voltage of the turn-off capacitors need to meet the maximum current of IGCT. The turn-off capacitor stack usually uses the aluminum electrolytic capacitor, which includes the disadvantages of large size, low life, and temperature limit. In order to reduce the volume and increase the life of the product, and also ensure the reliable of the turn-off process. This paper researches and explains the principle of the turn-off energy regenerative or dynamic adjustment topology, and analyzes the control strategy of the high-voltage turn-off topology, then the prototype test verifies that the topology obtains the same turn-off ability under the same current, but it can greatly reduces the capacity of the turnoff capacitors. And it can guarantee the dynamic and static characteristics of the turn-off process.","PeriodicalId":242596,"journal":{"name":"2021 Annual Meeting of CSEE Study Committee of HVDC and Power Electronics (HVDC 2021)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122262592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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