ABB REC650 - Thermal Overload Protection, One Time Constant Celsius;Fahrenheit LCPTTR;LFPTTR; Identification; Functionality

Function Range or value Accuracy
Operate time, non-directional
residual overvoltage
45 ms typically at 0.8 to 1.5 x
U
set
45 ms typically at 0.8 to 1.5 x U
set
Reset time, non-directional
residual overvoltage
85 ms typically at 1.2 to 0.8 x
U
set
85 ms typically at 1.2 to 0.8 x U
set
Operate time, directional
residual over current
140 ms typically at 0.5 to 2 x
I
set
-
Reset time, directional
residual over current
85 ms typically at 2 to 0.5 x I
set
-
Critical impulse time non-
directional residual over
current
35 ms typically at 0 to 2 x I
set
-
Impulse margin time non-
directional residual over
current
25 ms typically
-
6.6 Thermal overload protection, one time constant
Celsius/Fahrenheit LCPTTR/LFPTTR
6.6.1 Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Thermal overload protection, one time
constant, Celsius
LCPTTR 26
Thermal overload protection, one time
constant, Fahrenheit
LFPTTR 26
6.6.2 Functionality
The increasing utilizing of the power system closer to the thermal limits has generated
a need of a thermal overload protection also for power lines.
A thermal overload will often not be detected by other protection functions and the
introduction of the thermal overload protection can allow the protected circuit to
operate closer to the thermal limits.
The three-phase current measuring protection has an I
2
t characteristic with settable
time constant and a thermal memory. The temperature is displayed in either in Celsius
or in Fahrenheit depending on whether the function used is Thermal overload
protection one time constant, Celsius LCPTTR or Fahrenheit LFPTTR.
1MRK 511 287-UEN A Section 6
Current protection
121
Technical manual