In this paper,a passive muzzle arc control device(PMACD)of the augmented railguns is studied.By discussing its performance at different numbers of extra rails,a parameter optimization model is proposed.Through the cal...In this paper,a passive muzzle arc control device(PMACD)of the augmented railguns is studied.By discussing its performance at different numbers of extra rails,a parameter optimization model is proposed.Through the calculation model,it is found that the PMACD works well in the simple railgun,which refers to the gun that there is only one pair of rails in the inner bore.The PMACD may decrease the simple railgun’s armature peak current and muzzle arc,but affect its muzzle velocity not much.However,in the augmented railguns it has different characteristics.If the parameters of the PMACD are not selected suitable.It may increase the armature peak current and muzzle arc,but greatly decrease the velocity.The reason for this problem is that the extra rails generate a strong magnetic field in front of the armature,which induces a large current to change the armature current.It is also found that when the resistance and inductance parameters of the PMACD satisfy with the optimization formula,the PMACD can also play a good role in arc suppression in the augmented railguns.Experiments of an augmented railgun with a stainless steel PMACD are carried out to verify this optimization method.Results show that the muzzle arc is obviously controlled.This work may provide a reference for the design of the muzzle arc control device.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
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
基金acknowledge the Fundamental Research Funds for the Central Universities(Grants No 309190112102)the Natural Science Foundation of Jiangsu Province(Grants No BK20200493).
摘要In this paper,a passive muzzle arc control device(PMACD)of the augmented railguns is studied.By discussing its performance at different numbers of extra rails,a parameter optimization model is proposed.Through the calculation model,it is found that the PMACD works well in the simple railgun,which refers to the gun that there is only one pair of rails in the inner bore.The PMACD may decrease the simple railgun’s armature peak current and muzzle arc,but affect its muzzle velocity not much.However,in the augmented railguns it has different characteristics.If the parameters of the PMACD are not selected suitable.It may increase the armature peak current and muzzle arc,but greatly decrease the velocity.The reason for this problem is that the extra rails generate a strong magnetic field in front of the armature,which induces a large current to change the armature current.It is also found that when the resistance and inductance parameters of the PMACD satisfy with the optimization formula,the PMACD can also play a good role in arc suppression in the augmented railguns.Experiments of an augmented railgun with a stainless steel PMACD are carried out to verify this optimization method.Results show that the muzzle arc is obviously controlled.This work may provide a reference for the design of the muzzle arc control device.
摘要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。
摘要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。