In neutral point indirectly grounded systems, phase-to-ground fault is putting new demands on fault diagnosis technology. Information fusion is applied to detect the phase-to-ground fault, which integrates several sou...In neutral point indirectly grounded systems, phase-to-ground fault is putting new demands on fault diagnosis technology. Information fusion is applied to detect the phase-to-ground fault, which integrates several sources of information, including line current, line voltage, zero sequence current and voltage, and quintic harmonic wave component. This method is testified through the simulation of Matlab. Simulation results show that the precision and reliability of the detection has been greatly increased.展开更多
Fault location for distribution feeders short circuit especially single-phase grounding fault is an important task in distribution system with non-effectively grounded neutral.Fault location mode for distribution feed...Fault location for distribution feeders short circuit especially single-phase grounding fault is an important task in distribution system with non-effectively grounded neutral.Fault location mode for distribution feeders using fault generated current and voltage transient traveling waves was investigated.The characteristics of transient traveling waves resulted from each short circuit fault and their transmission disciplinarian in distribution feeders are analyzed.This paper proposed that double end travelling waves theory which measures arriving time of fault initiated surge at both ends of the monitored line is fit for distribution feeders but single end traveling waves theory not.According to different distribution feeders,on the basis of analyzing original traveling waves reflection rule in line terminal, Current-voltage mode,voltage-voltage mode and current-current mode for fault location based on traveling waves are proposed and aerial mode component of original traveling waves is used to realize fault location.Experimental test verify the feasibility and correctness of the proposed method.展开更多
1 Introduction The proposal of the concept of“New Power System”aims to illustrate the transform direction of the traditional power system,acting as the development core of the future new power grid.To achieve this,t...1 Introduction The proposal of the concept of“New Power System”aims to illustrate the transform direction of the traditional power system,acting as the development core of the future new power grid.To achieve this,the proposed strategic targets of“carbon neutralization and carbon peaking”must be implemented and insisted[1].The core feature of the new power system is that renewable energy plays a leading role and becomes the main source of energy supply,meanwhile,the goal of green energy utilization has also been put forward on the agenda.Green energy utilization includes two aspects,one is the exploitation and promotion of various green energy technologies,and the other is the digitalization of energy management.Under this trend,stochastic and fluctuating energy sources such as wind power and photovoltaic power replace deterministic controllable power sources such as thermal power,bringing challenges to power grid regulation and dispatching,as well as flexible operation.The large-scale integration of renewable energy and increasingly high proportion of power electronic equipment tend to bring about fundamental changes in the operation characteristics,safety control,and production mode of the power system.展开更多
面向“碳达峰、碳中和”目标,发展半波长输电技术可为构建以新能源为主体的新型电力系统提供能源保障。半波长技术因其输电距离远、经济性好等独特优势,在“西电东送”能源战略中有较好的应用前景。针对输电线路自然长度不足工频半波长...面向“碳达峰、碳中和”目标,发展半波长输电技术可为构建以新能源为主体的新型电力系统提供能源保障。半波长技术因其输电距离远、经济性好等独特优势,在“西电东送”能源战略中有较好的应用前景。针对输电线路自然长度不足工频半波长现象以及固定调谐的不足,文章提出一种变阻抗型可控调谐方法,基于可控串补(thyristor controlled series compensator,TCSC)阻抗控制策略构造可微调的调谐电感,基于电容三级投切策略构造可分级的调谐电容。对可控调谐可行性、故障过电压特征以及串补过压抑制进行仿真分析。结果表明,可控调谐能够消除电气长度误差,使线路保持半波长特性,线路补偿效果与可控调谐长度相关。展开更多
基金Supported by National Natural Science Foundation of China （60574083, 60811120024）, Graduate Innovation Research Foundation of Jiangsu Province （CX08B-090Z）, and Doctoral Innovation Foundation of Nanjing University of Aeronautics and Astronautics （BCXJ08-03）
文摘In neutral point indirectly grounded systems, phase-to-ground fault is putting new demands on fault diagnosis technology. Information fusion is applied to detect the phase-to-ground fault, which integrates several sources of information, including line current, line voltage, zero sequence current and voltage, and quintic harmonic wave component. This method is testified through the simulation of Matlab. Simulation results show that the precision and reliability of the detection has been greatly increased.
基金supported by Natural Science Foundation of Shandong Province(ZR2009FM054)
文摘Fault location for distribution feeders short circuit especially single-phase grounding fault is an important task in distribution system with non-effectively grounded neutral.Fault location mode for distribution feeders using fault generated current and voltage transient traveling waves was investigated.The characteristics of transient traveling waves resulted from each short circuit fault and their transmission disciplinarian in distribution feeders are analyzed.This paper proposed that double end travelling waves theory which measures arriving time of fault initiated surge at both ends of the monitored line is fit for distribution feeders but single end traveling waves theory not.According to different distribution feeders,on the basis of analyzing original traveling waves reflection rule in line terminal, Current-voltage mode,voltage-voltage mode and current-current mode for fault location based on traveling waves are proposed and aerial mode component of original traveling waves is used to realize fault location.Experimental test verify the feasibility and correctness of the proposed method.
文摘1 Introduction The proposal of the concept of“New Power System”aims to illustrate the transform direction of the traditional power system,acting as the development core of the future new power grid.To achieve this,the proposed strategic targets of“carbon neutralization and carbon peaking”must be implemented and insisted[1].The core feature of the new power system is that renewable energy plays a leading role and becomes the main source of energy supply,meanwhile,the goal of green energy utilization has also been put forward on the agenda.Green energy utilization includes two aspects,one is the exploitation and promotion of various green energy technologies,and the other is the digitalization of energy management.Under this trend,stochastic and fluctuating energy sources such as wind power and photovoltaic power replace deterministic controllable power sources such as thermal power,bringing challenges to power grid regulation and dispatching,as well as flexible operation.The large-scale integration of renewable energy and increasingly high proportion of power electronic equipment tend to bring about fundamental changes in the operation characteristics,safety control,and production mode of the power system.
文摘面向“碳达峰、碳中和”目标,发展半波长输电技术可为构建以新能源为主体的新型电力系统提供能源保障。半波长技术因其输电距离远、经济性好等独特优势,在“西电东送”能源战略中有较好的应用前景。针对输电线路自然长度不足工频半波长现象以及固定调谐的不足,文章提出一种变阻抗型可控调谐方法,基于可控串补(thyristor controlled series compensator,TCSC)阻抗控制策略构造可微调的调谐电感,基于电容三级投切策略构造可分级的调谐电容。对可控调谐可行性、故障过电压特征以及串补过压抑制进行仿真分析。结果表明,可控调谐能够消除电气长度误差,使线路保持半波长特性,线路补偿效果与可控调谐长度相关。
文摘虚拟同步机VSG(virtual synchronous generator)通过模拟同步机特性为新能源并网提供惯性和阻尼。然而,电力电子开关器件高频开关过程中可能会发生断路故障,导致输出电流波形严重畸变,影响电网安全稳定运行。针对中点箝位型NPC(neutral point clamped)三电平VSG桥臂故障问题,提出一种中点电压均衡的VSG容错模型预测控制策略。分析NPC三电平VSG单相桥臂故障后运行机理,在开关器件故障后利用直流侧电容组成虚拟桥臂,重构为VSG桥臂故障容错结构。建立故障情况下预测电流模型,重构故障状态空间电压矢量,将直流侧中点电容电压引入容错模型代价函数,减小电容电压波动,实现VSG桥臂故障容错运行。实验结果表明,在开关器件发生故障后,NPC三电平VSG能容错连续运行,验证了所提模型预测容错控制策略的有效性,提高了VSG运行可靠性。
