Advantages of neutral grounding:
- Voltage of phases are limited to phase to ground voltage.
- High voltages due to arcing grounds or transient line-ground faults are eliminated.
- Sensitive protective relays against LG faults can be used.
- Overvoltages due to lightening are discharged to ground.
Advantages of isolated neutral
- It is possible to maintain supply with fault on line.
- Interference with communication lines is reduced because of no Z sequence current.
Effective grounding systems:
X0 / X1 < 3
Least Expensive is = maxm Vphase= 0.8 V line