Non-Directional Neutral Overcurrent Protection 51N/50N And Non-Directional Ground Fault Protection 51G/50G; Identification; Function Block; Functionality - ABB RELION 620 Series Technical Manual

Section 4
Protection functions
4.1.4
4.1.4.1
4.1.4.2
4.1.4.3
188
Characteristic
Reset ratio
Retardation time
Trip time accuracy in definite time mode
Trip time accuracy in inverse time mode
Suppression of harmonics
Measurement mode and Pol quantity = default, current before fault = 0.0 × I
1)
V , f = 60 Hz, fault current in one phase with nominal frequency injected from random phase angle, results
n n
based on statistical distribution of 1000 measurements
2) Includes the delay of the signal output contact
3) Maximum Pickup value = 2.5 × I
Non-directional neutral overcurrent protection 51N/50N and
Non-directional ground fault protection 51G/50G

Identification

Function description
Non-directional ground-fault protection,
low stage
Non-directional ground-fault protection,
high stage
Non-directional ground-fault protection,
instantaneous stage

Function block

A070432-ANSI V1 EN
Figure 85: Function block

Functionality

The ground-fault function 51N/50N or 51G/50G is used as non-directional ground-fault
protection.
Value
Typically 0.96
<35 ms
±1.0% of the set value or ±20 ms
±5.0% of the theoretical value or ±20 ms
DFT: -50 dB at f = n × f
, Pickup value multiples in range of 1.5 to 20
n
IEC 61850 IEC 60617
identification identification
EFLPTOC Io>
EFHPTOC Io>>
EFIPTOC Io>>>
1MAC504801-IB E
3)
, where n = 2, 3, 4, 5,...
n
, voltage before fault = 1.0 ×
n
ANSI/IEEE C37.2
device number
51N/G
50N/G-1/2
50N/G-3
620 series ANSI
Technical Manual