ABB RET670 Product Manual page 56

Transformer protection RET670 ANSI
Pre-configured
Product version: 1.2
Table 30. Thermal overload protection, two time constants TRPTTR (49)
Function
Base current 1 and 2
Operate time:
æ ö
2 2
-
I I
p
ç ÷
t
= ×
t ln
ç ÷
2 2
-
I I
è ø
b
(Equation 1)
EQUATION1356 V1 EN
I = I
measured
Alarm pickup 1 and 2
Operate current
Reset level temperature
Table 31. Breaker failure protection CCRBRF (50BF)
Function
Operate phase current
Reset ratio, phase current
Operate residual current
Reset ratio, residual current
Phase current pickup for blocking of
contact function
Reset ratio
Timers
Operate time for current detection
Reset time for current detection
Table 32. Broken conductor check BRCPTOC (46)
Function
Minimum phase current for operation
Unbalance current operation
Timer
56
Range or value
IBase
(30–250)% of
I = load current before overload
p
occurs
Time constant τ = (1–500)
minutes
(50–99)% of heat content trip
value
IBase
(50–250)% of
(10–95)% of heat content trip
Range or value
lBase
(5-200)% of
> 95%
lBase
(2-200)% of
> 95%
(5-200)% of lBase
> 95%
(0.000-60.000) s
10 ms typically
15 ms maximum
Range or value
IBase
(5–100)% of
(0–100)% of maximum current
(0.00-6000.00) s
1MRK 504 118-BUS A
Accuracy
± 1.0% of I
n
IEC 60255–8, class 5 + 200 ms
± 2.0% of heat content trip
± 1.0% of I
n
± 2.0% of heat content trip
Accuracy
± 1.0% of I at I £ I
n
± 1.0% of I at I > I
-
± 1.0% of I at I £ I
n
± 1.0% of I at I > I
-
± 1.0% of I at I £ I
n
± 1.0% of I at I > I
-
± 0.5% ±10 ms
-
-
Accuracy
± 0.1% of I
n
± 0.1% of I
n
± 0.5% ± 10 ms
n
n
n
n
n
n
ABB