ABB RET630 - Underfrequency Protection Main Settings; Transformer Differential Protection of Two-Winding Transformers

Table 62. Underfrequency protection (DAPTUF) main settings
Parameter Function Value (Range) Step
Start value DAPTUF 35.0...64.0 Hz 0.1
Operate delay time DAPTUF 0.170...60.000 s 0.001
Table 63. Transformer differential protection of two-winding transformers (TR2PTDF)
Characteristic Value
Operation accuracy At the frequency f = f
n
±1.5% of the set value or ±0.002 × I
n
Operate time
1)2)
Biased low stage
Instantaneous high
stage
Typical 35 ms (±5ms)
Typical 17 ms (±5ms)
Reset time < 30 ms
Reset ratio Typical 0.96
Retardation time < 35 ms
Suppression of harmonics DFT: -50 dB at f = n x f
n
, where n = 2, 3, 4, 5,
…
1) Current before fault = 0.0 × I
n
, f
n
= 50 Hz. Injected differential current = 2.0 × set operate value
2) Includes the delay of the output contact value and f
n
= 50 Hz
Transformer Protection and Control 1MRS756788 A
RET630
Product version: 1.0 Issued: 15.09.2009
ABB 43