ABB RET620 - Directional Earth-Fault Protection (Defxpdef) Main Settings; Negative Phase-Sequence Overcurrent Protection (NSPTOC)

Table 36. Directional earth-fault protection (DEFxPDEF) main settings
Parameter Function Value (Range) Step
Start Value DEFLPDEF 0.010...5.000 x I
n
0.005
DEFHPDEF 0.10...40.00 x I
n
0.01
Directional mode DEFLPDEF and DEFHPDEF 1=Non-directional
2=Forward
3=Reverse
Time multiplier DEFLPDEF 0.05...15.00 0.01
DEFHPDEF 0.05...15.00 0.01
Operate delay time DEFLPDEF 60...200000 ms 10
DEFHPDEF 40...200000 ms 10
Operating curve type
1)
DEFLPDEF Definite or inverse time
Curve type: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19
DEFHPDEF Definite or inverse time
Curve type: 1, 3, 5, 15, 17
Operation mode DEFLPDEF and DEFHPDEF 1=Phase angle
2=IoSin
3=IoCos
4=Phase angle 80
5=Phase angle 88
1) For further reference, refer to the Operating characteristics table
Table 37. Negative phase-sequence overcurrent protection (NSPTOC)
Characteristic
Value
Operation accuracy Depending on the frequency of the current measured: f
n
±2 Hz
±1.5% of the set value or ±0.002 x I
n
Start time
1)2)
Minimum Typical Maximum
I
Fault
= 2 x set Start value
I
Fault
= 10 x set Start value
22 ms
14 ms
24 ms
16 ms
25 ms
17 ms
Reset time < 40 ms
Reset ratio Typical 0.96
Retardation time < 35 ms
Operate time accuracy in definite time mode ±1.0% of the set value or ±20 ms
Operate time accuracy in inverse time mode
±5.0% of the theoretical value or ±20 ms
3)
Suppression of harmonics DFT: -50 dB at f = n x f
n
, where n = 2, 3, 4, 5,…
1) Negative sequence current before fault = 0.0, f
n
= 50 Hz, results based on statistical distribution of 1000 measurements
2) Includes the delay of the signal output contact
3) Maximum Start value = 2.5 x I
n
, Start value multiples in range of 1.5 to 20
Transformer Protection and Control
1MRS757846 A
RET620
Product version: 2.0
ABB 31