Grounding in IT-system
Grounding in IT-system
(OP)
Why is there, on an 230 V IT-system (isolated neutral) on a ship, 127 V between ground and phase when there is no connection between tranformers neutral and earth?
Is this because of the capacitive currents in the long cables?
Thanx
Harry F
Is this because of the capacitive currents in the long cables?
Thanx
Harry F






RE: Grounding in IT-system
RE: Grounding in IT-system
Be well aware that on an ungrounded system (capacitance only ø-grd) transients may develop up to several times the ø-ø voltage, from intermittent ground faults and resonant effects.
RE: Grounding in IT-system
RE: Grounding in IT-system
Correctly sized high-resistance grounding can be desirable for damping transient and resonant overvoltages that inevitably occur on the inherent ø-grd capacitance.
Particles vary widely, but to get an idea of related problems experienced by some, read though Thread238-3370 and Thread238-6870. We’re approaching 50 years of warnings on ungrounded LV distribution.
RE: Grounding in IT-system
RE: Grounding in IT-system
Why is there, on an 230 V IT-system (isolated neutral) on a ship, 127 V between ground and phase when there is no connection between tranformers neutral and earth?
///There just may be a fault, namely one line has become grounded.\\\
Is this because of the capacitive currents in the long cables?
///Alternately, yes.\\\
RE: Grounding in IT-system
RE: Grounding in IT-system
if one line has become grounded, fharry would have measured 230V between the two other lines and ground, 127V could be caused by a grounded neutral.
fharry should check if the 127V he measures are able to supply some current (e.g. a small light bulb).If the volatge sgoes down in that case, its jsut capacitive coupling.