Table 276: Conversion table between one and two time constants
Single time constant (min)
Short time constant
(min)
Long time constant
(min)
Weighting factor p
10 1.1 17 0.4
15 1.6 25 0.4
20 2.1 33 0.4
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.
4.1.5.6 Signals
Table 277: 49T 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
AMB_TEMP FLOAT32 0 The ambient temperature used in the calculation
Section 4 1MAC059074-MB A
Protection functions
282 615 series ANSI
Technical Manual
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