Start Sensitivity - ABB REG670 Technical Manual

Section 8
Current protection
8.12.7.1
440
Operate
time
t1Max
(Default= 1000 s)
t1Min
(Default= 5 s)
IEC09000691 V2 EN
Figure 202: Inverse time characteristic with t1Min and t1Max
For a detailed description of inverse time characteristic, see chapter
characteristics".
The reset time is exponential and is given by the following expression:


ResetMultip

ResetTime s [ ]
=

I
 
NS
 −


I
  
Start
EQUATION2111 V4 EN
Where
I is the measured negative sequence current
NS
I is the desired start level in pu of rated generator current
Start
ResetMultip is multiplier of the generator capability constant
reset time of inverse time characteristic

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.
IEC09000691-2-en.vsd



K
⋅
2

1


1MRK502052-UEN B
K1
Current I2-1>
"Inverse
(Equation 98)
K equal to setting K 1 and thus defines
Technical manual