Thermal Overload Protection, Two Time Constants Trpttr; Identification; Functionality - ABB REG650 Technical Manual

Section 8
Current protection
8.4
8.4.1
8.4.2
214
Function
Operate time, non-directional
residual overvoltage
Reset time, non-directional
residual overvoltage
Operate time, directional
residual over current
Reset time, directional
residual over current
Critical impulse time non-
directional residual over
current
Impulse margin time non-
directional residual over
current
Thermal overload protection, two time constants
TRPTTR

Identification

Function description
Thermal overload protection, two time
constants

Functionality

If a power transformer or generator reaches very high temperatures the equipment
might be damaged. The insulation within the transformer/generator will have forced
ageing. As a consequence of this the risk of internal phase-to-phase or phase-to-earth
faults will increase. High temperature will degrade the quality of the transformer/
generator insulation.
The thermal overload protection estimates the internal heat content of the transformer/
generator (temperature) continuously. This estimation is made by using a thermal
model of the transformer/generator with two time constants, which is based on current
measurement.
Two warning levels are available. This enables actions in the power system to be done
before dangerous temperatures are reached. If the temperature continues to increase to
the trip value, the protection initiates a trip of the protected transformer/generator.
Range or value
45 ms typically at 0.8 to 1.5 x
U
set
85 ms typically at 1.2 to 0.8 x
U
set
140 ms typically at 0.5 to 2 x
I
set
85 ms typically at 2 to 0.5 x I
set
35 ms typically at 0 to 2 x I
set
25 ms typically
IEC 61850
identification
TRPTTR
1MRK 502 048-UEN A
Accuracy
45 ms typically at 0.8 to 1.5 x U
85 ms typically at 1.2 to 0.8 x U
-
-
-
-
IEC 60617 ANSI/IEEE C37.2
identification device number
49
SYMBOL-A V1 EN
Technical manual
set
set