A BLOCK input signal resets NS2PTOC (46I2) momentarily.
When the parameter
CurveType
1 is set to
Inverse
, an inverse curve is selected according to
selected value for parameter
K
1. The minimum trip time setting of parameter
t1Min
and reset time
parameter
ResetMultip1
also influence step operation. However, to match the heating
characteristics of the generator, the reset time is depending on the setting of parameter
K
1, which
must be set according to the generators negative sequence current capacity.
EQUATION2112 V1 EN-US
Where:
I
2
is negative sequence current expressed in per unit of the rated generator current
t is operating time in seconds
K is a constant [s], which depends on generator size and design
Current I2-1>
Operate
time
t1Min
t1Max
(Default= 1000 s)
(Default= 5 s)
K1
IEC09000691-2-en.vsd
IEC09000691 V2 EN-US
Figure 299: 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
NS
Pickup
[ ]
−
= ⋅
2
1
KK1
ANSIEQUATION2111 V1 EN-US
(Equation 162)
1MRK 502 066-UUS B Section 8
Current protection
565
Technical manual
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