Electric towers of high voltage transmission lines are more exposed to natural lightning phenomena thanks to their high heights. These lines are crossed by powerful current sources to dissipate in the ground, which ca...Electric towers of high voltage transmission lines are more exposed to natural lightning phenomena thanks to their high heights. These lines are crossed by powerful current sources to dissipate in the ground, which can, at one time or another, create disturbances or other phenomena can be generated. This is why we have set ourselves the objective of studying the FDTD modeling of the influence of direct lightning strikes on the power transmitted by a High-Voltage power line. To do this, we have implemented Kirchhoff’s laws to model the power transmitted by a High-Voltage power line in a steady state. Calculating the electromagnetic field generated by lightning requires the lightning current along the channel and its spatiotemporal distribution, the bi-exponential models and that of engineers were chosen and used to reproduce the physical phenomena best. Several works have been published in the literature and various mathematical models are proposed, to study the filamentous nature of power lines which has led to a more flexible modelling, based on the transmission line model, associated with the field theory developed from Maxwell’s equations, which explain the interaction between a lightning wave and a power transmission line. The resolution of the line equations in the lightning shock regime was the subject of the FDTD method to obtain the results in the spatio-temporal domain. Through this research, we are interested in the study of the spatiotemporal distribution of the lightning current wave to model the radiated electromagnetic field and to examine the influence of the overvoltage induced by the atmospheric discharge on the transportable power of a High Voltage AC Transmission line, for good selective protection to illuminate the parasites. 2D simulations based on proposed models were developed as well as the verification of the consistency of the different models, by comparing the fractal dimensions of the results of our program with those of the figures obtained experimentally. The aspects developed in this article could have direct implications in practical applications in the engineering and design of high-voltage transmission systems.展开更多
The demands for massive renewable energy integration, passive network power supply, and global energy interconnection have all gradually increased, posing new challenges for high voltage direct current(HVDC) power tra...The demands for massive renewable energy integration, passive network power supply, and global energy interconnection have all gradually increased, posing new challenges for high voltage direct current(HVDC) power transmission systems, including more complex topology and increased diversity of bipolar HVDC transmission. This study proposes that these two factors have led to new requirements for HVDC control strategies. Moreover, due to the diverse applications of HVDC transmission technology, each station in the system has different requirements. Furthermore, the topology of the AC-DC converter is being continuously developed, revealing a trend towards hybrid converter stations.展开更多
In view of the imbalanced distribution of power load and resources, including the status of “electric shortage” in some cities in our country, the article discusses the long-distance transmission technology. It main...In view of the imbalanced distribution of power load and resources, including the status of “electric shortage” in some cities in our country, the article discusses the long-distance transmission technology. It mainly analyzed two ways of the long-distance transmission: UHV AC transmission and UHV DC transmission. The fractional frequency transmission technology and half wavelength AC transmission technology of AC transmission are introduced. Some key technologies of long-distance transmission are described. It has a guess for long-distance transmission future direction.展开更多
随着柔性直流(direct current,DC)异步互联工程相继推进,高水电占比高带来的超低频振荡问题威胁着电力系统频率的稳定。针对超低频振荡现象的发生,提出基于柔性直流输电即电压源换流器的高压直流输电(voltage source converter based hi...随着柔性直流(direct current,DC)异步互联工程相继推进,高水电占比高带来的超低频振荡问题威胁着电力系统频率的稳定。针对超低频振荡现象的发生,提出基于柔性直流输电即电压源换流器的高压直流输电(voltage source converter based high voltage direct current transmission,VSC-HVDC)系统的附加频率控制策略。首先,构建含水电、火电机组的频率响应模型,通过阻尼转矩分析揭示超低频振荡产生机理,明确各类调速器参数以及不同水电占比对系统超低频振荡发生的影响;随后,根据直流电容电压与交流系统频率耦合特性,对换流站参与抑制超低频振荡机理进行研究,提出换流站虚拟惯性与V_(DC)-f下垂的控制方式,并通过约束条件对虚拟惯性与下垂参数进行设计;最后,基于MATLAB/SIMULINK平台搭建含水电、火电机组的负荷频率控制模型,通过对比水轮机参数优化方法验证所提方法的有效性。展开更多
针对换相失败恢复过程中直流电流预测难度大的问题,首先对直流线路的等效模型进行分析,建立整流侧直流电压与逆变侧各电气量之间的定量关系,结合直流控制分析提出一种可准确预测直流电流变化量的方法。其次,基于最小关断面积判别与直流...针对换相失败恢复过程中直流电流预测难度大的问题,首先对直流线路的等效模型进行分析,建立整流侧直流电压与逆变侧各电气量之间的定量关系,结合直流控制分析提出一种可准确预测直流电流变化量的方法。其次,基于最小关断面积判别与直流电流变化量的预测方法,构建后续换相失败风险评估模型,并根据风险评估结果实现对触发角的定量控制,从而抑制后续换相失败的发生。以PSCAD/EMTDC平台中的国际大电网会议(conseil interna-tional des grands reseaux elecctriques,CIGRE)标准模型为测试系统,不同故障类型、严重程度及故障持续时间下的仿真结果验证了所提直流电流预测、后续换相失败风险评估的准确性和后续换相失败抑制策略的有效性。展开更多
随着中国经济的持续增长,对能源的需求也在不断上升。然而,由于一次能源与负荷中心的逆向分布,采用新能源进行大规模远距离输电已成为行业内的迫切需求。在众多输电技术中,基于换相换流器的高压直流输电技术(line commutated converter ...随着中国经济的持续增长,对能源的需求也在不断上升。然而,由于一次能源与负荷中心的逆向分布,采用新能源进行大规模远距离输电已成为行业内的迫切需求。在众多输电技术中,基于换相换流器的高压直流输电技术(line commutated converter high voltage direct current,LCC-HVDC)具有无功消耗特性,可能加剧电网的电压波动与无功平衡的问题。针对这一挑战,重点研究交直流混联电网,并构建了一个旨在优化无功功率的数学模型。为克服遗传算法在初始种群选取困难和易早熟的问题,对传统遗传算法进行了创新性改进。在改进后的IEEE 14节点系统和IEEE 39节点系统上进行系列实验验证,所提改进遗传算法展现出显著的实用性和有效性。该算法能够有效优化电网的无功功率,显著提升电网运行的稳定性和效率,为电网无功优化提供了一种新的解决方案。展开更多
深入分析高压直流(High Voltage Direct Current,HVDC)输电系统对电力通信网络的多方面需求,详细阐述HVDC输电系统的电力通信网络架构设计,包括网络拓扑结构、通信节点布局与网络分层功能划分。探讨适用于HVDC输电系统的通信技术与协议...深入分析高压直流(High Voltage Direct Current,HVDC)输电系统对电力通信网络的多方面需求,详细阐述HVDC输电系统的电力通信网络架构设计,包括网络拓扑结构、通信节点布局与网络分层功能划分。探讨适用于HVDC输电系统的通信技术与协议选型,并着重研究HVDC输电系统的电力通信网络的可靠性设计,涵盖冗余设计、故障检测与自愈机制以及网络安全防护措施等,旨在为构建稳定、安全且高效的HVDC电力通信网络提供全面的理论依据与技术参考。展开更多
文摘Electric towers of high voltage transmission lines are more exposed to natural lightning phenomena thanks to their high heights. These lines are crossed by powerful current sources to dissipate in the ground, which can, at one time or another, create disturbances or other phenomena can be generated. This is why we have set ourselves the objective of studying the FDTD modeling of the influence of direct lightning strikes on the power transmitted by a High-Voltage power line. To do this, we have implemented Kirchhoff’s laws to model the power transmitted by a High-Voltage power line in a steady state. Calculating the electromagnetic field generated by lightning requires the lightning current along the channel and its spatiotemporal distribution, the bi-exponential models and that of engineers were chosen and used to reproduce the physical phenomena best. Several works have been published in the literature and various mathematical models are proposed, to study the filamentous nature of power lines which has led to a more flexible modelling, based on the transmission line model, associated with the field theory developed from Maxwell’s equations, which explain the interaction between a lightning wave and a power transmission line. The resolution of the line equations in the lightning shock regime was the subject of the FDTD method to obtain the results in the spatio-temporal domain. Through this research, we are interested in the study of the spatiotemporal distribution of the lightning current wave to model the radiated electromagnetic field and to examine the influence of the overvoltage induced by the atmospheric discharge on the transportable power of a High Voltage AC Transmission line, for good selective protection to illuminate the parasites. 2D simulations based on proposed models were developed as well as the verification of the consistency of the different models, by comparing the fractal dimensions of the results of our program with those of the figures obtained experimentally. The aspects developed in this article could have direct implications in practical applications in the engineering and design of high-voltage transmission systems.
基金supported by the State Grid Science & Technology Project (GEIGC-E-[2018]026)
文摘The demands for massive renewable energy integration, passive network power supply, and global energy interconnection have all gradually increased, posing new challenges for high voltage direct current(HVDC) power transmission systems, including more complex topology and increased diversity of bipolar HVDC transmission. This study proposes that these two factors have led to new requirements for HVDC control strategies. Moreover, due to the diverse applications of HVDC transmission technology, each station in the system has different requirements. Furthermore, the topology of the AC-DC converter is being continuously developed, revealing a trend towards hybrid converter stations.
文摘In view of the imbalanced distribution of power load and resources, including the status of “electric shortage” in some cities in our country, the article discusses the long-distance transmission technology. It mainly analyzed two ways of the long-distance transmission: UHV AC transmission and UHV DC transmission. The fractional frequency transmission technology and half wavelength AC transmission technology of AC transmission are introduced. Some key technologies of long-distance transmission are described. It has a guess for long-distance transmission future direction.
文摘随着柔性直流(direct current,DC)异步互联工程相继推进,高水电占比高带来的超低频振荡问题威胁着电力系统频率的稳定。针对超低频振荡现象的发生,提出基于柔性直流输电即电压源换流器的高压直流输电(voltage source converter based high voltage direct current transmission,VSC-HVDC)系统的附加频率控制策略。首先,构建含水电、火电机组的频率响应模型,通过阻尼转矩分析揭示超低频振荡产生机理,明确各类调速器参数以及不同水电占比对系统超低频振荡发生的影响;随后,根据直流电容电压与交流系统频率耦合特性,对换流站参与抑制超低频振荡机理进行研究,提出换流站虚拟惯性与V_(DC)-f下垂的控制方式,并通过约束条件对虚拟惯性与下垂参数进行设计;最后,基于MATLAB/SIMULINK平台搭建含水电、火电机组的负荷频率控制模型,通过对比水轮机参数优化方法验证所提方法的有效性。
文摘针对换相失败恢复过程中直流电流预测难度大的问题,首先对直流线路的等效模型进行分析,建立整流侧直流电压与逆变侧各电气量之间的定量关系,结合直流控制分析提出一种可准确预测直流电流变化量的方法。其次,基于最小关断面积判别与直流电流变化量的预测方法,构建后续换相失败风险评估模型,并根据风险评估结果实现对触发角的定量控制,从而抑制后续换相失败的发生。以PSCAD/EMTDC平台中的国际大电网会议(conseil interna-tional des grands reseaux elecctriques,CIGRE)标准模型为测试系统,不同故障类型、严重程度及故障持续时间下的仿真结果验证了所提直流电流预测、后续换相失败风险评估的准确性和后续换相失败抑制策略的有效性。
文摘随着中国经济的持续增长,对能源的需求也在不断上升。然而,由于一次能源与负荷中心的逆向分布,采用新能源进行大规模远距离输电已成为行业内的迫切需求。在众多输电技术中,基于换相换流器的高压直流输电技术(line commutated converter high voltage direct current,LCC-HVDC)具有无功消耗特性,可能加剧电网的电压波动与无功平衡的问题。针对这一挑战,重点研究交直流混联电网,并构建了一个旨在优化无功功率的数学模型。为克服遗传算法在初始种群选取困难和易早熟的问题,对传统遗传算法进行了创新性改进。在改进后的IEEE 14节点系统和IEEE 39节点系统上进行系列实验验证,所提改进遗传算法展现出显著的实用性和有效性。该算法能够有效优化电网的无功功率,显著提升电网运行的稳定性和效率,为电网无功优化提供了一种新的解决方案。
文摘深入分析高压直流(High Voltage Direct Current,HVDC)输电系统对电力通信网络的多方面需求,详细阐述HVDC输电系统的电力通信网络架构设计,包括网络拓扑结构、通信节点布局与网络分层功能划分。探讨适用于HVDC输电系统的通信技术与协议选型,并着重研究HVDC输电系统的电力通信网络的可靠性设计,涵盖冗余设计、故障检测与自愈机制以及网络安全防护措施等,旨在为构建稳定、安全且高效的HVDC电力通信网络提供全面的理论依据与技术参考。
