Steady State Current Of NGR

It's mostly for safety, and to protect the system...

http://www.littelfuse.com/~/media/protection-relays/white-papers/littelfuse_white_paper_ground_fault_el731.pdf

There shouldn't be a steady state current.

This sounds very like homework.

A Natural Gamma Ray (NGR) is a very high energy, massless, neutrally charged particle. Without a charge there will not be any electric current regardless of the flux density until this ionizing radiation interacts with some detecting media (gas). Then it depends on the detecting media and which region [ion chamber, proportional counter or Geiger-Muller] the bias field imposes on the media.

A neutral-grounding -resistor (i assume you mean this) i thought, carries current for a short time. This is an adiabatic process, and is quite different from the steady-state rating. So, in my mind, the two ratings can't be related linearly or in some simple way. i am curious to learn from other experts here.

If we are talking about a neutral grounding resistor (I hate undefined acronyms) then the steady state current will neither be steady or zero. Assuming (another word I hate) that a power distribution fault is not happening, the current flowing through this resistor will be from two possible sources.

One of these sources will be a ground loop from the circuit path. This is impossible to determine due to the lack of information given by the OP and I just do not feel like dealing with Maxwell's equations today.

The other source will be the thermal current production known as the Johnson-Nyquist noise. As the name implies, this will be a chaotic current that every resistor produces. Due to the chaotic nature of this current a measurement bandwidth of frequencies must be selected to calculate this value.

As per standards steady state rating NGR is meant for the temperature rise. Neutral Grounded Resistor shall operate under ground fault condition for more than of 90 days per year and /or it to keep the temperature rise below 385 degree. Current rating will be different for low resistance and High resistance NGRs

<...operate under ground fault condition for more than of 90 days per year...>

That would be one dangerous installation!

Yes it is dangerous. But NGR should capable for withstanding that.

What standards would they be?

Please refer IEEE 32

A1) Zero

A2) It doesn't have one.

An NGR will have to deal with the third harmonic currents circulating in the system due to generator or transformer magnetising currents or triplen harmonics due to VFDs / Thyristor panels in the system or simple stray currents circulating in the system through the system neutral.

These are steady state currents and cause heating in the NGR. That's how the NGR will have steady state rating (needless to say much much less in magnitude) as well apart from short time rating.

So why don't those currents stay in the neutral, Boss? Why do they pass through the NGR if there isn't a fault?

Some views here have left me shaken. i have always thought that any current flowing to earth is undesirable, and steps must be taken to quickly isolate the faulty circuit so that the cause of such a fault is located and eliminated. Now to think that a steady-state current can flow for what can only be an unproductive purpose, is incomprehensible to me.

Dumb maybe, but would like some elementary clarification.

If you read IEEE 32, it will be clarified.

Regettably, i have no access to a copy. So i will have to wait for someone to explain to me. Perhaps you can summarise for me?

Wow, here is what one page from a Google search shows

i still can't believe this ! Thank God this is not my field

This is why I hate to answer power distribution questions. Only people properly trained and authorized should ever touch power distribution equipment. Those people authorized and risking their lives to do this work, rely on a proper design that will not kill them. CR4 provides neither training nor authority to work on power distribution equipment. As stated in our FAQ, CR4 is not a homework cheat site. It is likely the OP is too lazy to do their own homework (not all homework is scholastic) to answer their curiosity because Google and other search engines can obviously find this information.