When, in a coal mine distribution network whose neutral point is grounded by an arc suppression coil (ASC), a fault occurs in the ASC, compensation cannot be properly realized. Furthermore, it can damage the safe and ...When, in a coal mine distribution network whose neutral point is grounded by an arc suppression coil (ASC), a fault occurs in the ASC, compensation cannot be properly realized. Furthermore, it can damage the safe and reliable run of the network. We first introduce a three-phase five-column arc suppression coil (TPFCASC) and discuss its autotracking compensation theory. Then we compare the single phase to ground fault of the coal mine distribution network with an open phase fault at the TPFCASC using the Thévenin theory, the symmetrical-component method and the complex sequence network respectively. The results show that, in both types of faults, zero-sequence voltage of the network will appear and the maximum magnitude of this zero-sequence voltage is different in both faults. Based on this situation, a protection for the open phase fault at the TPFCASC should be estab-lished.展开更多
When single phase earth fault occurs in the arc suppression coil grounding system, the amplitude of the transient capacitance current is high and decays fast, but the attenuation of the transient inductance current is...When single phase earth fault occurs in the arc suppression coil grounding system, the amplitude of the transient capacitance current is high and decays fast, but the attenuation of the transient inductance current is much slower. This paper analyses the DC component of fault branch, and has found it is much bigger than that of the normal branches in transient state. All the simulation results obtained from three compensation types, different fault time and different wave cycles show that the DC component of fault branch is much higher than that of those normal branches. These results verify the effectiveness of taking the DC component as the method of fault line selection in the arc suppression coil grounding system.展开更多
Combined with actual situation of Fengxian power Supply Company, the neutral grounding modes of Fengxian 35 kV and 10 kV power grid are studied in the paper. The different frequencies injected method is used to measur...Combined with actual situation of Fengxian power Supply Company, the neutral grounding modes of Fengxian 35 kV and 10 kV power grid are studied in the paper. The different frequencies injected method is used to measure the capacitive current of Fengxian 28 substations, and the neutral grounding modes of the 28 substations are determined based on the measured values of capacitive current.展开更多
针对当前的有源消弧方法因谐波电流检测精度不足而效果较差,以及传统消弧线圈在谐波影响下容易导致消弧失败的问题,设计了一种无须谐波检测便可有效抑制故障点残流中谐波分量的新型消弧线圈。该消弧线圈由逆变器并联传统消弧线圈构成,...针对当前的有源消弧方法因谐波电流检测精度不足而效果较差,以及传统消弧线圈在谐波影响下容易导致消弧失败的问题,设计了一种无须谐波检测便可有效抑制故障点残流中谐波分量的新型消弧线圈。该消弧线圈由逆变器并联传统消弧线圈构成,其中逆变器的指令电压根据中性点电位进行调整,可使逆变器支路不产生基波电流;逆变器的低谐波阻抗特性可有效降低故障点残流中的谐波分量;同时传统消弧线圈过补偿可抵消电容电流。经过Matlab和PSCAD/EMTDC(power systems computer aided design/electromagnetic transients including direct current)仿真,结果显示新型消弧线圈将故障点处的5次谐波、7次谐波分别由25.62、65.85 A降低到了0.11、0.57 A,能够实现可靠消弧。该研究在配电网消弧领域具有一定的应用前景。展开更多
文摘When, in a coal mine distribution network whose neutral point is grounded by an arc suppression coil (ASC), a fault occurs in the ASC, compensation cannot be properly realized. Furthermore, it can damage the safe and reliable run of the network. We first introduce a three-phase five-column arc suppression coil (TPFCASC) and discuss its autotracking compensation theory. Then we compare the single phase to ground fault of the coal mine distribution network with an open phase fault at the TPFCASC using the Thévenin theory, the symmetrical-component method and the complex sequence network respectively. The results show that, in both types of faults, zero-sequence voltage of the network will appear and the maximum magnitude of this zero-sequence voltage is different in both faults. Based on this situation, a protection for the open phase fault at the TPFCASC should be estab-lished.
文摘When single phase earth fault occurs in the arc suppression coil grounding system, the amplitude of the transient capacitance current is high and decays fast, but the attenuation of the transient inductance current is much slower. This paper analyses the DC component of fault branch, and has found it is much bigger than that of the normal branches in transient state. All the simulation results obtained from three compensation types, different fault time and different wave cycles show that the DC component of fault branch is much higher than that of those normal branches. These results verify the effectiveness of taking the DC component as the method of fault line selection in the arc suppression coil grounding system.
文摘Combined with actual situation of Fengxian power Supply Company, the neutral grounding modes of Fengxian 35 kV and 10 kV power grid are studied in the paper. The different frequencies injected method is used to measure the capacitive current of Fengxian 28 substations, and the neutral grounding modes of the 28 substations are determined based on the measured values of capacitive current.
文摘针对当前的有源消弧方法因谐波电流检测精度不足而效果较差,以及传统消弧线圈在谐波影响下容易导致消弧失败的问题,设计了一种无须谐波检测便可有效抑制故障点残流中谐波分量的新型消弧线圈。该消弧线圈由逆变器并联传统消弧线圈构成,其中逆变器的指令电压根据中性点电位进行调整,可使逆变器支路不产生基波电流;逆变器的低谐波阻抗特性可有效降低故障点残流中的谐波分量;同时传统消弧线圈过补偿可抵消电容电流。经过Matlab和PSCAD/EMTDC(power systems computer aided design/electromagnetic transients including direct current)仿真,结果显示新型消弧线圈将故障点处的5次谐波、7次谐波分别由25.62、65.85 A降低到了0.11、0.57 A,能够实现可靠消弧。该研究在配电网消弧领域具有一定的应用前景。
