ABB RELION REX640 Technical Manual page 1131

1MRS759142 F
Characteristic
Reset time
Reset ratio
Operate time accuracy in definite
time mode
Operate time accuracy in inverse
definite minimum time mode
Suppression of harmonics
4.12.3 Three-phase current unbalance protection for shunt
capacitor banks HCUBPTOC (ANSI 60P)
4.12.3.1 Identification
Function description
Three-phase current unbalance pro-
tection for shunt capacitor banks
4.12.3.2 Function block
Figure 632: Function block symbol
4.12.3.3 Functionality
The three-phase current unbalance protection function for shunt capacitor banks
HCUBPTOC is used to protect the H-bridge capacitor banks against internal faults.
HCUBPTOC is suitable for protection of internally fused, externally fused and fuse-
less capacitor bank applications.
HCUBPTOC has two stages of operation, the operation stage and alarm stage.
In the operation stage, HCUBPTOC starts when the measured unbalance current
exceeds the set limit. The operating time characteristics can be selected to be
either definite time (DT) or inverse definite minimum time (IDMT). In the alarm
stage, the alarm starts when the measured unbalance current exceeds the set alarm
limit. The alarm time characteristics are based on DT.
HCUBPTOC contains blocking functionality. It is possible to block the function
outputs, timers or the function itself.
1
Fundamental frequency current = 1.0 × I
value , results based on statistical distribution of 1000 measurements
2
Includes the delay of the signal output contact
REX640
Technical Manual
Value
Typically 40 ms
Typically 0.96
1 % of the theoretical value or ±20 ms
5 % of the theoretical value or ±20 ms
DFT: -50 dB at f = n × f
IEC 61850
identification
HCUBPTOC
, current before fault = 0.0 × I
n
Protection functions
, where n = 2,3,4,5,..
n
IEC 60617 ANSI/IEEE C37.2
identification device number
3dI>C 60P
, fault current = 2.0 ×
n
Start
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