In the distribution network system with its neutral point grounding via arc suppression coil, when single-phase grounding fault occurred near zero-crossing point of the phase voltage, the inaccuracy of the line select...In the distribution network system with its neutral point grounding via arc suppression coil, when single-phase grounding fault occurred near zero-crossing point of the phase voltage, the inaccuracy of the line selection always existed in existing methods. According to the characteristics that transient current was different between the fault feeder and other faultless feeders, wavelet transformation was performed on data of the transient current within a power frequency cycle after the fault occurred. Based on different fault angles, wavelet energy in corresponding frequency band was chosen to compare. The result was that wavelet energy in fault feeder was the largest of all, and it was larger than sum of those in other faultless feeders, when the bus broke down, the disparity between each wavelet energy was not significant. Fault line could be selected out by the criterion above. The results of MATLAB/simulink simulation experiment indicated that this method had anti-interference capacity and was feasible.展开更多
单相接地故障的高质量调控是支撑新型配电网安全运行的重要环节,针对有源消弧装置AASD(active-type arc suppression device)功能单一、成本高昂等问题,提出1种基于异构单元的有源消弧装置HU-AASD(AASD based on heterogeneous unit)拓...单相接地故障的高质量调控是支撑新型配电网安全运行的重要环节,针对有源消弧装置AASD(active-type arc suppression device)功能单一、成本高昂等问题,提出1种基于异构单元的有源消弧装置HU-AASD(AASD based on heterogeneous unit)拓扑结构及调控策略。首先,HU-AASD利用第四桥臂为虚拟中性点提供电压支撑,使得三相桥臂的耐压需求被降低至相电压,从而降低了AASD的器件成本与体积;其次,所提方案兼具容性和感性无功补偿能力,且接地故障发生后HU-AASD可不间断地向电网提供无功补偿,从而为配电网提供不间断的电压支撑;最后,仿真及实验结果验证了所提拓扑及调控策略的有效性及可行性。展开更多
选相选线是配电网单相接地故障有效治理的关键环节。针对现有选相选线方法在高阻接地故障时辨识能力不足、适应性差的问题,该文提出一种基于特征电流变化量的配电网高阻接地故障主动选相选线方法。首先,分析了单相接地故障前后零序电压...选相选线是配电网单相接地故障有效治理的关键环节。针对现有选相选线方法在高阻接地故障时辨识能力不足、适应性差的问题,该文提出一种基于特征电流变化量的配电网高阻接地故障主动选相选线方法。首先,分析了单相接地故障前后零序电压特征分量的变化规律及其响应机理;其次,通过对比健全相与故障相特征电流变化量辐角主值(characteristic current variation principle value,CCV-PV)的特性差异,构建了基于母线CCV-PV的故障主动选相方法;再次,通过比较健全馈线与故障馈线的CCV-PV特性差异,构建了基于馈线CCV-PV故障主动选线方法。理论分析和仿真验证表明:仅需有源消弧装置注入特征电流即可实现接地故障的主动选相和选线,并且所提方法在高阻接地故障、三相零序不对称、非同步采样等复杂场景下均具有较高的灵敏度。展开更多
凭借兼具无功功率支撑(reactive power support,RPS)与接地故障调控(grounding fault control,GFC)能力,复合装置得到广泛关注。但是,现有复合装置存在容量过高、需要额外附加供电装置的问题。针对上述问题,基于充分利用既有站内资源的...凭借兼具无功功率支撑(reactive power support,RPS)与接地故障调控(grounding fault control,GFC)能力,复合装置得到广泛关注。但是,现有复合装置存在容量过高、需要额外附加供电装置的问题。针对上述问题,基于充分利用既有站内资源的思想,提出一种基于站内资源的新型无功功率支撑与接地故障调控复合装置(RPS and GFC composite device,RGCD)。首先,介绍RGCD的拓扑结构与运行原理,RGCD由站内电容器、站内消弧线圈和多功能变流器(multi-functional converter,MC)构成,当电网正常运行时,站内电容器补偿负荷所需的大部分无功功率,剩余部分由MC进行补偿;当发生单相接地故障时,站内电容器进行无功补偿,站内消弧线圈和MC进行接地故障调控,在不同运行模式下均实现了MC容量降低。其次,分析接地故障调控期间的能量流动机理,并提出基于直流侧电压稳定的P-Q两相消弧方法,实现免供电装置下RGCD的稳定运行。最后,通过仿真验证了所提拓扑及运行原理的有效性与可行性。展开更多
文摘In the distribution network system with its neutral point grounding via arc suppression coil, when single-phase grounding fault occurred near zero-crossing point of the phase voltage, the inaccuracy of the line selection always existed in existing methods. According to the characteristics that transient current was different between the fault feeder and other faultless feeders, wavelet transformation was performed on data of the transient current within a power frequency cycle after the fault occurred. Based on different fault angles, wavelet energy in corresponding frequency band was chosen to compare. The result was that wavelet energy in fault feeder was the largest of all, and it was larger than sum of those in other faultless feeders, when the bus broke down, the disparity between each wavelet energy was not significant. Fault line could be selected out by the criterion above. The results of MATLAB/simulink simulation experiment indicated that this method had anti-interference capacity and was feasible.
文摘单相接地故障的高质量调控是支撑新型配电网安全运行的重要环节,针对有源消弧装置AASD(active-type arc suppression device)功能单一、成本高昂等问题,提出1种基于异构单元的有源消弧装置HU-AASD(AASD based on heterogeneous unit)拓扑结构及调控策略。首先,HU-AASD利用第四桥臂为虚拟中性点提供电压支撑,使得三相桥臂的耐压需求被降低至相电压,从而降低了AASD的器件成本与体积;其次,所提方案兼具容性和感性无功补偿能力,且接地故障发生后HU-AASD可不间断地向电网提供无功补偿,从而为配电网提供不间断的电压支撑;最后,仿真及实验结果验证了所提拓扑及调控策略的有效性及可行性。
文摘选相选线是配电网单相接地故障有效治理的关键环节。针对现有选相选线方法在高阻接地故障时辨识能力不足、适应性差的问题,该文提出一种基于特征电流变化量的配电网高阻接地故障主动选相选线方法。首先,分析了单相接地故障前后零序电压特征分量的变化规律及其响应机理;其次,通过对比健全相与故障相特征电流变化量辐角主值(characteristic current variation principle value,CCV-PV)的特性差异,构建了基于母线CCV-PV的故障主动选相方法;再次,通过比较健全馈线与故障馈线的CCV-PV特性差异,构建了基于馈线CCV-PV故障主动选线方法。理论分析和仿真验证表明:仅需有源消弧装置注入特征电流即可实现接地故障的主动选相和选线,并且所提方法在高阻接地故障、三相零序不对称、非同步采样等复杂场景下均具有较高的灵敏度。
文摘凭借兼具无功功率支撑(reactive power support,RPS)与接地故障调控(grounding fault control,GFC)能力,复合装置得到广泛关注。但是,现有复合装置存在容量过高、需要额外附加供电装置的问题。针对上述问题,基于充分利用既有站内资源的思想,提出一种基于站内资源的新型无功功率支撑与接地故障调控复合装置(RPS and GFC composite device,RGCD)。首先,介绍RGCD的拓扑结构与运行原理,RGCD由站内电容器、站内消弧线圈和多功能变流器(multi-functional converter,MC)构成,当电网正常运行时,站内电容器补偿负荷所需的大部分无功功率,剩余部分由MC进行补偿;当发生单相接地故障时,站内电容器进行无功补偿,站内消弧线圈和MC进行接地故障调控,在不同运行模式下均实现了MC容量降低。其次,分析接地故障调控期间的能量流动机理,并提出基于直流侧电压稳定的P-Q两相消弧方法,实现免供电装置下RGCD的稳定运行。最后,通过仿真验证了所提拓扑及运行原理的有效性与可行性。
