共查询到19条相似文献,搜索用时 296 毫秒
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分析了配电网暂态零模电流的分布情况,引入了相关性理论,根据故障线路的暂态零模电流有效值最大且与非故障线路的内积小于0,故障点两侧的暂态零模电流极性相反,波形差异大,相关系数小于阀值且接近0的特征,利用暂态零模电流进行配电网故障选线、定位,给出了故障定位步骤。MATLAB仿真结果表明,基于暂态零模电流的配电网故障选线、定位方法正确,具有不受电压初相角、接地电阻、中性点接地方式制约等优点。 相似文献
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针对小电流接地系统单相接地故障自动选线问题,对基于小波分析理论的选线方法进行深入的研究和分析。第一步简述中性点接地的几种方式,讨论小电流接地系统中这几种接地方式的基本原理以及发生故障情况后的电量变化。第二步结合系统故障时的暂态零序电流特征与小波分析理论提出新的选线方法,采用模值极大值判别法解决故障选线问题。第三步通过MATLAB软件里的SIMULINK搭建仿真模型,选取小电流系统在不同支路电压幅值和接地电阻大小等情况下,提出了依据故障线路与非故障线路的首半波尖峰方向和幅值大小进行选线的方法。结果验证了所提故障选线方法的正确性和有效性。 相似文献
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针对配网小电流接地故障选线准确性差的问题,该文在波形相似度理论基础上,研究了配网小电流接地故障选线技术。分析配网小电流接地故障高频分量、电流工作频率的变化量和非线性电阻产生的高频分量,给出了故障线路和非故障线路的暂态直流分量方向,在此基础上,利用暂态零序列电流波形伸缩变换选线原理判断小电流接地故障线路。通过模糊K均值聚类选线方法进行接地故障电路选线,设计矩阵隶属线路的隶属度,根据计算结果给出选线结果及流程。选择一个具有6条线路的接地系统进行实验,结果表明,当小电流接地电弧线圈的单相接地故障表现为间断性电流分量故障时,利用所研究的技术进行配网小电流接地故障选线的准确性高、可靠性好。 相似文献
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摘要: 针对架空-电缆混合线路中的高阻瞬时接地故障和架空线路雷击故障,提出采用电流故障行波的2个特征频带中的频谱能量比和波形系数来有效区分雷击非故障与雷击故障、高阻弧光接地故障的思想。利用电磁暂态软件建立仿真模型对架空-电缆混合线路的各种雷击情况进行了仿真,并且对故障行波信号进行了识别研究。仿真结果表明,采用的雷击识别方法可以有效识别不同类型的故障。 相似文献
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中性点经小电阻接地系统存在高阻和间歇性弧光接地故障,以及故障持续、越级跳闸等故障扩大事故,严重的还会烧毁小电阻设备。基于高阻接地、间歇性弧光接地故障的特征,选取中性点小电阻阻值,约束继电保护,基于电流不平衡度突变、暂态分析及故障累积检测,给出继电保护策略。经仿真验证:该文提出策略具备灵敏性、有效性,能够解决小电阻系统的保护盲区,是对原有小电阻接地系统继电保护的有益补充。 相似文献
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针对谐振接地系统发生单相接地故障后的选线准确度问题,尤其是故障发生在相电压过零点及最大值附近时灵敏度欠缺的问题,首先分析零序网络故障暂态电流的特性,探讨健全线路与故障线路的阻抗特性,然后将零序电流和电压导数的相关系数作为判据,充分地利用了馈线暂态零序电流中的衰减直流分量、工频分量和高频分量,提出一种高、低频段下的相关分析故障选线方法,最后从故障合闸角、过渡电阻两方面仿真验证了所提方法的有效性。 相似文献
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提出一种经验模态分解和决策树相结合的风光储直流微电网配电线路故障检测和分类方法。该方法通过经验模态分解对发送端测得的直流电流进行分解,得到多个本征模态函数,并采用最大加权相关系数方法计算选取灵敏度最高的2个本征模态函数,将9个统计方法应用于本征模态函数生成故障特征值,最终基于决策树,实现风光储直流微电网配电线路的精准检测和分类。算例分析表明,基于经验模态分解的风光储直流微电网配电线路故障检测方法可不受故障电阻、故障起始时刻和故障距离的影响,快速有效的对配电线故障进行检测和分类。 相似文献
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Lu QU Zhanqing YU Qiang SONG Zhichang YUAN Biao ZHAO Dawei YAO Jianfu CHEN Yao LIU Rong ZENG 《Frontiers in Energy》2019,13(1):120
The DC distribution system is an important development direction of the distribution system, which can improve the reliability and the quality of the power supply, and support the new energy, the energy storage, the electric vehicles, and the flexible access of AC and DC loads to grid. To realize the demonstration application of the DC distribution technology, China’s first demonstration project of the medium voltage DC distribution network will be built in Zhuhai, Guangdong Province to support the construction of the city energy internet. First, this paper analyzes the demand of the DC distribution network project, and puts forward the construction content and construction target. Then, it designs and analyzes the electrical connection mode, system operation mode, and startup and shutdown mode of the DC distribution network, and proposes the overall project construction plan. Finally, it conducts the specific project design and analysis, which mainly include the selection of equipment such as inverters, DC transformers and DC circuit breakers, the design and analysis of the DC control and protection system, the design and analysis of the over-voltage protection and the configuration scheme of the lightning arrester, and analysis of the system transient characteristics. The design and analysis of the engineering program is a combination of China’s distribution network engineering practice and technical characteristics, which lays a solid foundation for the advancement of the DC power distribution technology in China, and has reference value and demonstration effect for the design and construction of other projects. 相似文献
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《全球能源互联网(英文)》2021,4(1):91-103
Development of the medium and low voltage DC distribution system is of great significance to a regional transmission of electric energy, increasing a penetration rate of new energy, and enhancing a safety of the operation of the AC/DC interconnected grid. This paper first summarizes the medium and low voltage DC distribution system schemes and plans put forward by many countries, and then elaborate status of under-construction medium and low voltage DC distribution system project cases in China. Based on these project cases, this paper analyzes key issues involved in the medium and low voltage DC distribution system topologies, equipment, operation control technologies and DC fault protections, in order to provide theoretical and technical reference for future medium and low voltage DC distribution system-related projects. Finally, this paper combines a current China research status to summarize and give a prediction about the future research direction of medium and low voltage DC distribution system, which can provide reference for the research of medium and low voltage DC distribution system. 相似文献
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风电、光伏等可再生能源以逆变型分布式电源(IIDG)形式并网后,使配电网成为有源配电网,其接地故障分布特点与传统配电网不同。文章通过分析恒功率控制型和低电压穿越控制型IIDG故障电流特性,建立其故障等值模型,然后,针对不接地系统建立计及IIDG的单相接地故障分析模型,分析并网变压器中性点不同接地方式和IIDG的接入位置下,故障点电流以及IIDG至故障点间线路零序电流特征分布,最后,通过PSCAD/EMTDC建立含IIDG接入的配电网故障仿真模型,验证了单相接地故障建模及分析方法的有效性。 相似文献
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以输入并联输出串联(IPOS)型Boost全桥隔离变换器(BFBIC)为研究对象,针对其内部故障发生后无法迅速定位的问题,提出基于波形积分法的故障诊断策略。该策略通过选取变换器内部固定测量点,基于运行机理分析变换器发生硬故障或直流汇集线路故障时各电气量的波形特征,并通过总结特征规律对故障位置进行识别。针对现有冗余桥臂方案在BFBIC-IPOS上不适用的问题,提出利用冗余升压单元实现内部故障穿越的保护策略。该策略通过更改器件参数及冗余单元备用状态,避免升压单元投切过程中的过流、过压问题。最后,通过PSIM建模仿真,验证故障诊断策略及冗余保护策略的有效性。 相似文献
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《全球能源互联网(英文)》2020,3(6):585-594
Distribution networks in China and several other countries are predominantly neutral inefficiently grounding systems (NIGSs), and more than 80% of the faults in distribution networks are single-phase-to-ground (SPG) faults. Because of the weak fault current and imperfect monitoring equipment configurations, methods used to determine the faulty line sections with SPG faults in NIGSs are ineffective. The development and application of distribution-level phasor measurement units (PMUs) provide further comprehensive fault information for fault diagnosis in a distribution network. When an SPG fault occurs, the transient energy of the faulted line section tends to be higher than the sum of the transient energies of other line sections. In this regard, transient energy-based fault location algorithms appear to be a promising resolution. In this study, a field test plan was designed and implemented for a 10 kV distribution network. The test results demonstrate the effectiveness of the transient energy-based SPG location method in practical distribution networks. 相似文献