ABB Relion 611 Series, Technical Manual

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In stressed situations in the power system, the lines and cables may be required to be
overloaded for a limited time. This should be done without any risk for the above-
mentioned risks.
The thermal overload protection provides information that makes temporary
overloading of cables and lines possible. The thermal overload protection estimates
the conductor temperature continuously. This estimation is made by using a thermal
model of the line/cable that is based on the current measurement.
If the temperature of the protected object reaches a set warning level, a signal is given
to the operator. This enables actions in the power system to be done before dangerous
temperatures are reached. If the temperature continues to increase to the maximum
allowed temperature value, the protection initiates a trip of the protected line.
4.1.3.6 Signals
Table 118: T1PTTR Input signals
Name Type Default Description
I_A SIGNAL 0 Phase A current
I_B SIGNAL 0 Phase B current
I_C SIGNAL 0 Phase C current
ENA_MULT BOOLEAN 0=False Enable Current multiplier
BLK_OPR BOOLEAN 0=False Block signal for operate outputs
AMB_TEMP FLOAT32 0 The ambient temperature used in the calculation
Table 119: T1PTTR Output signals
Name Type Description
OPERATE BOOLEAN Operate
ALARM BOOLEAN Thermal Alarm
BLK_CLOSE BOOLEAN Thermal overload indicator. To inhibite reclose.
START BOOLEAN Start
4.1.3.7 Settings
Table 120: T1PTTR Group settings (Basic)
Parameter Values (Range) Unit Step Default Description
Env temperature Set -50...100 °C 1 40 Ambient temperature used when no
external temperature measurement
available
Current reference 0.05...4.00 xIn 0.01 1.00 The load current leading to Temperature
raise temperature
Temperature rise 0.0...200.0 °C 0.1 75.0 End temperature rise above ambient
Time constant 60...60000 s 1 2700 Time constant of the line in seconds.
Table continues on next page
1MRS757454 D
Section 4
Protection functions
611 series 135
Technical Manual