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.
Estimated time to trip before operation is presented.
8.5.3 Function block
TRPTTR
I3P*
BLOCK
COOLING
RESET
TRIP
START
ALARM1
ALARM2
LOCKOUT
WARNING
IEC08000037 V1 EN
Figure 76: TRPTTR function block
8.5.4 Signals
TRPTTR is not provided with external temperature sensor in first
release of 650 series. The only input that influences the temperature
measurement is the binary input COOLING.
Table 91: TRPTTR Input signals
Name
Type Default Description
I3P GROUP
SIGNAL
- Three phase group signal for current input
BLOCK BOOLEAN 0 Block of function
COOLING BOOLEAN 0 Cooling input changes IBase setting and time
constant
RESET BOOLEAN 0 Reset of function
Table 92: TRPTTR Output signals
Name
Type Description
TRIP BOOLEAN Trip Signal
START BOOLEAN Start signal
ALARM1 BOOLEAN First level alarm signal
ALARM2 BOOLEAN Second level alarm signal
LOCKOUT BOOLEAN Lockout signal
WARNING BOOLEAN Trip within set warning time
1MRK 504 135-UEN A Section 8
Current protection
173
Technical manual
To Next Page
Loading...
