a10jp,
it is almost the same.To decipher the numerous numbers and letters that protection experts use,refer to IEEE std C37.2-2008 Device Function Numbers,acronyms and contact designation.Equivalent IEC is 61850-7-4.
"The suffix N is preferred when the device is connected in the residual of a polyphase circuit, is connected across a broken delta, or is internally derived from the polyphase current or voltage quantities. The suffix G is preferred where the measured quantity is in the path to ground, or, in the case of ground fault detectors, is the current flowing to ground. See Figure C.2 in Annex C for examples."
Similarly "Device number 59—overvoltage relay
A device that operates when its input voltage exceeds a predetermined value." etc,etc
Let me share some "stories" on the subject.
In mid 70's, when one of the earliest 400 KV transformer banks were commisioned in India-it was a 250 MVA bank with 11 kV tertiary formed by power cables,one corner of the delta was earthed.After a couple of monsoon rains,one of the cable developed ground fault creating a L-L fault on tertiary causing tertiary winding failure.
To overcome this, we removed one corner earthing and put three single phase PTs (with primary neutral grounded) at tertiary terminals with 110/3 V secondary winding connected in broken delta to 59N relay.So in case of a LG fault on any line,59N relay will pick up 110 V residual voltage to give alarm.
After some years,during mid 80's I had to face a case where 20-50 v was coming across the broken delta without any apparant earthing on tertiary bus anywhere. Cliet was not ready to accept the transformer suspecting some defect.
Then I found out that American GE and Westinghouse engineers had experienced the same problem in ungrounded MV systems during mid 40's and they explained the reason for this neutral displacement as the resonance between the inductance and capacitance of the tertiary circuit.Solution for this is to connect surge absorbers (capacitors) to tertiary terminals (which we did) or connect a resistor in the closed delta of the PT.Those old AIEE papers saved my skin at that time.