ABB REG670 - Start Sensitivity

Current I2-1>
Operate
time
t1Min
t1Max
(Default= 1000 s)
(Default= 5 s)
K1
IEC09000691-2-en.vsd
IEC09000691 V2 EN
Figure 202: Inverse time characteristic with t1Min and t1Max
For a detailed description of inverse time characteristic, see chapter "Inverse
characteristics".
The reset time is exponential and is given by the following expression:
ResetTime s
ResetMultip
I
I
K
NS
Start
[ ]






−












= ⋅
2
1
EQUATION2111 V4 EN (Equation 98)
Where
I
NS
is the measured negative sequence current
I
Start
is the desired start level in pu of rated generator current
ResetMultip is multiplier of the generator capability constant K equal to setting K 1 and thus defines
reset time of inverse time characteristic
8.12.7.1 Start sensitivity
The trip start levels Current I2-1> and I2-2> of NS2PTOC are freely settable over a
range of 3 to 500 % of rated generator current IBase. The wide range of start setting
is required in order to be able to protect generators of different types and sizes.
Section 8 1MRK502052-UEN B
Current protection
440
Technical manual