Single time constant
(min)
Short time constant
(min)
Long time constant
(min)
Weighting factor p
25 2.6 41 0.4
30 3.1 49 0.4
35 3.6 58 0.4
40 4.1 60 0.4
45 4.8 75 0.4
50 5.1 82 0.4
55 5.6 90 0.4
60 6.1 98 0.4
65 6.7 107 0.4
70 7.2 115 0.4
75 7.8 124 0.4
The default Max temperature setting is 105°C. This value is chosen since even
though the IEC 60076-7 standard recommends 98°C as the maximum allowable
temperature in long-time loading, the standard also states that a transformer can
withstand the emergency loading for weeks or even months, which may produce
the winding temperature of 140°C. Therefore, 105°C is a safe maximum
temperature value for a transformer if the Max temperature setting value is not
given by the transformer manufacturer.
4.1.6.6 Signals
Table 238: T2PTTR 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
BLOCK BOOLEAN 0=False Block signal for activating the blocking mode
TEMP_AMB FLOAT32 0 The ambient temperature used in the calculation
Table 239: T2PTTR Output signals
Name
Type Description
OPERATE BOOLEAN Operate
START BOOLEAN Start
ALARM BOOLEAN Thermal Alarm
BLK_CLOSE BOOLEAN Thermal overload indicator. To inhibite reclose.
Section 4 1YHT530004D05 D
Protection functions
238 615 series
Technical Manual
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