Hybrid Grounding Mode for 10 kV Distribution System using Regional Isolation Technology

Abstract

The 10kV distribution networks are mostly mixed lines of overhead lines and cables. When the neutral point of the system is grounded by arc suppression coil, the power supply reliability of the system is high, but the fault point is difficult to locate. Additionally, with the increasing use of cables, it is difficult for the arc suppression coil to effectively compensate the capacitive current of the system. If the system is grounded with small resistance, the fault point can be accurately located, but the reliability of power supply will be reduced, so it is difficult to choose the neutral grounding mode. In response to this situation, combining these two grounding modes, a hybrid grounding mode is proposed, which can guarantee the power supply reliability of the system and quickly cut off cable line faults. For the high proportion of cables in distribution networks, Petersen coil is installed at the neutral but the cables are isolated to create a regional system with small resistance grounding mode. A numerical simulation model of hybrid grounding Theoretical analysis and simulations of a 10 kV distribution network with hybrid grounding mode are carried out to validate the proposed method.