Thermal Overload Protection, Two Time Constants Trpttr (49) - ABB REB650 Technical Manual

1MRK 505 277-UUS C
7.3
7.3.1
7.3.2
7.3.3
Technical Manual
Thermal overload protection, two time constants
TRPTTR (49)
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-ground
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 pickup 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.
Function block
TRPTTR (49)
I3P* TRIP
BLOCK PICKUP
COOLING ALARM1
RESET ALARM2
LOCKOUT
WARNING
ANSI08000037-1-en.vsd
ANSI08000037 V1 EN
Figure 41: TRPTTR (49) function block
IEC 61850 IEC 60617
identification identification
TRPTTR
SYMBOL-A V1 EN
Section 7
Current protection
ANSI/IEEE C37.2
device number
49
101