ABB RELION REX640 Technical Manual page 1119

1MRS759142 F
Characteristic
Start time for under current stage
3
Reset time for overload and alarm
stage
Reset ratio
Operate time accuracy in definite
time mode
Operate time accuracy in inverse
time mode
Suppression of harmonics for under
current stage
4.12.2 Current unbalance protection for capacitor banks
CUBPTOC (ANSI 60N)
4.12.2.1 Identification
Table 1063: Function identification
Function description
Current unbalance protection for
shunt capacitor banks
4.12.2.2 Function block
Figure 627: Function block symbol
4.12.2.3 Functionality
The current unbalance protection for shunt capacitor banks function CUBPTOC
is used to protect the double-Y-connected capacitor banks from internal faults.
CUBPTOC is suitable for the protection of internally fused, externally fused and
fuseless applications.
CUBPTOC has two stages of operation, that is, operation stage and alarm stage.
In the operating stage, CUBPTOC starts when the measured unbalance current
1
Harmonics current before fault = 0.5 × I
on statistical distribution of 1000 measurements
2
Includes the delay of the signal output contact
3
Harmonics current before fault = 1.2 × I
on statistical distribution of 1000 measurements
REX640
Technical Manual
Value
2,
Typically 26 ms
Typically 60 ms
Typically 0.96
1 % of the set value or ±20 ms
10 % of the theoretical value or ±20 ms
DFT: -50 dB at f = n × fn, where n = 2,3,4,5,..
IEC 61850
identification
CUBPTOC
, harmonics fault current 1.5 ×
n
, harmonics fault current 0.8 ×
n
Protection functions
IEC 60617 ANSI/IEEE C37.2
identification device number
dI>C 60N
Start value , results based
Start value , results based
1119