ABB RET615, Product Manual

Page: 41 / 68

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