合理选择中性点接地电阻柜的阻值,不仅可以释放单相接地电弧的后半波能量
合理选择中性点接地电阻柜的阻值,不仅可以释放单相接地电弧的后半波能量,而且可以降低电弧重燃的可能性,抑制电网过电压的辐射值,提高继电保护装置对电网的动作灵敏度跳闸接地电阻,从而有效地保护系统的正常运行。中性点接地电阻柜是一套完整的接地设备,包括接地变压器,可安装在电厂电力系统、变电所供电系统、工矿企业配电系统中,从而实现中性点经电阻接地的系统运行方式。中性点接地电阻柜原理:限流电气保护装置,接于变压器中性点与接地之间。电网在正常运行期间不工作。当出现故障时,变压器中性点电压会发生偏移。当中性点接地电阻柜装置动作时,配电网中性点可强制接地,限制其故障电流,使继电保护装置有足够的时间检测、实现跳闸和备用切换,避免损坏配电网和电气设备。
Reasonable selection of resistance value of neutral point grounding resistance cabinet can not only release the second half wave energy of single-phase grounding arc, but also reduce the possibility of arc re ignition, inhibit the radiation value of grid overvoltage, improve the action sensitivity of relay protection device to the grid, trip the grounding resistance, and effectively protect the normal operation of the system. Neutral point grounding resistance cabinet is a complete set of grounding equipment, including grounding transformer, which can be installed in power plant power system, substation power supply system, industrial and mining enterprise distribution system, so as to realize the system operation mode of neutral point grounding through resistance. Principle of neutral grounding resistance cabinet: current limiting electrical protection device, connected between transformer neutral point and grounding. The grid does not operate during normal operation. When there is a fault, the neutral point voltage of transformer will shift. When the neutral point grounding resistance cabinet device acts, the neutral point of the distribution network can be forced to ground to limit its fault current, so that the relay protection device has enough time to detect, realize tripping and standby switching, and avoid damaging the distribution network and electrical equipment.