ABB Relion 670 Series Product Manual page 76

Bay control REC670
Version 2.2
Table 43. Thermal overload protection, one time constant LCPTTR/LFPTTR
Function
Reference current
Reference temperature
Operate time:


2 , 2
I I

σ
< p
t ln
 ,
T T
2 , Trip Amb √
I

 T
ref
EQUATION13000039 V3 EN-US
T = set operate temperature
Trip
T = ambient temperature
Amb
T = temperature rise above ambient at I
ref
I = reference load current
ref
I = actual measured current
I = load current before overload occurs
p
Alarm temperature
Operate temperature
Reset level temperature
Table 44. Thermal overload protection, two time constants TRPTTR
Function
Base current 1 and 2
Operate time:
∑ ⌡
2 2
,
I I
p
 
σ
< √
t ln
 
2 2
,
I I
 
Trip
(Equation 2)
EQUATION1356 V3 EN-US
I = actual measured current
Ip = load current before
overload occurs
ITrip = steady state operate
IBasex
current level in % of
Alarm level 1 and 2
Operate current
Reset level temperature
76
Range or value
(2-400)% of IBase
(0-300)°C, (0 - 600)°F
Time constant t = (1–1000)
minutes




2
I

ref

(Equation 1)
ref
(0-200)°C, (0-400)°F
(0-300)°C, (0-600)°F
(0-300)°C, (0-600)°F
Range or value
IBase
(30–250)% of
Time constant τ = (0.10–
500.00) minutes
(50–99)% of heat content
operate value
(50–250)% of IBase
(10–95)% of heat content trip
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M12352-1 v15
Accuracy
±1.0% of I
r
±1.0°C, ±2.0°F
IEC 60255-149, ±5.0% or ±200 ms whichever is greater
±2.0°C, ±4.0°F
±2.0°C, ±4.0°F
±2.0°C, ±4.0°F
M13266-2 v9
Accuracy
±1.0% of I
r
±5.0% or ±200 ms whichever is greater
±2.0% of heat content trip
±1.0% of I
r
±2.0% of heat content trip
1MRK 511 404-BEN N
Hitachi Power Grids