Neutral Grounding Resistor IEC

[timm33333]

In NEMA, the minimum voltage at which NGR (neutral grounding resistor) is allowed is 480V. What is the minimum voltage in IEC at which NGR is allowed? Thanks.

 

[7anoter4]

In my opinion you have to search this in IEC 60076-25[still in draft].

 

[timm33333]

Sorry I meant to say that what is the general practice in IEC world: is NGR (neutral grounding resistor) used at low voltage, or is it only used at Medium Voltage?

 

[Kiribanda]

From my experience in IEC world, I can say that either Low Resistance Grounding or Soild Grounding
with a coordinated ground fault protection scheme are widely used in both low & medium oltage systems.
To my knowledge there is no IEC (or even an ANSI/ IEEE standard) specifying the minimum
voltage that a NGR is allowed. The application depends on soil resistivity and other grounding practices.
In ANSI world, 25kV is the preferred volatge limit because beyond 25kV capacitance is becoming a problem during a ground fault.

 

[GroovyGuy]

Hi Tim,
I am pretty sure that 230V hi-resistance ngrs are used on 400/230V 3P4W systems in the iec world.
Regards,
GG


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