ABB RET615 Product Manual page 41

ABB
Transformer Protection and Control
RET615
Product version: 4.0
Table 41. Thermal overload for protection, two time constants (T2PTTR) main settings
Parameter
Temperature rise
Max temperature
Operate temperature
Weighting factor p
Short time constant
Current reference
Operation
Table 42. Transformer differential protection of two-winding transformers (TR2PTDF)
Characteristic
Operation accuracy
1)2)
Operate time
Reset time
Reset ratio
Suppression of harmonics
1) Current before fault = 0.0, f = 50 Hz, results based on statistical distribution of 1000 measurements
n
2) Includes the delay of the output contact. When differential current = 2 x set operate value and f
Function
T2PTTR
T2PTTR
T2PTTR
T2PTTR
T2PTTR
T2PTTR
T2PTTR
Low stage
High stage
Value (Range)
o
0.0...200.0 C
o
0.0...200.0 C
80.0...120.0 %
0.00...1.00
6...60000 s
0.05...4.00 x I
n
Off
On
Value
Depending on the frequency of the current measured: f
±2 Hz
±3.0% of the set value or ±0.002 x I
Minimum Typical
34 ms 40 ms
21 ms 22 ms
< 40 ms
Typical 0.96
DFT: -50 dB at f = n x f , where n = 2, 3, 4, 5, ...
n
= 50 Hz.
n
1MRS756891 F
Step
0.1
0.1
0.1
0.01
1
0.01
-
n
n
Maximum
44 ms
24 ms
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