Characteristic
Value
Reset time
Typically 40 ms
Reset ratio
Typically 0.96
Operate time accuracy in definite
time mode
1 % of the theoretical value or ±20 ms
Operate time accuracy in inverse
definite minimum time mode
5 % of the theoretical value or ±20 ms
Suppression of harmonics
DFT: -50 dB at f = n × f
n
, where n = 2,3,4,5,..
4.12.3
Three-phase current unbalance protection for shunt
capacitor banks HCUBPTOC (ANSI 60P)
4.12.3.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Three-phase current unbalance pro-
tection for shunt capacitor banks
HCUBPTOC
3dI>C
60P
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
n
, current before fault = 0.0 × I
n
, fault current = 2.0 ×
Start
value, results based on statistical distribution of 1000 measurements
2
Includes the delay of the signal output contact
1MRS759142 F
Protection functions
REX640
Technical Manual
1131