ABB RES670 Technical Manual page 311

1MRK 511 408-UUS A
Phasor measurement unit RES670 2.2 ANSI
Technical manual
Exponent
-
é ù
V VMin
(
= ×
t t MaxTripDelay t MinTripDelay _
ê ú
ë - û
VNom VMin
EQUATION1559 V1 EN-US
where:
t
V
Exponent
VMin, VNom
t_MaxTripDelay, t_MinTripDelay are time settings.
The inverse time characteristics are shown in figure 105, for:
VMin = 90%
= 100%
t_MaxTrip = 1.0 s
Delay
t_MinTripD = 0.0 s
elay
Exponent = 0, 1, 2, 3 and 4
1
Exponenent
0.5
0
90
ANSI05000075 V1 EN-US
Figure 105: Voltage dependent inverse time characteristics for underfrequency
protection SAPTUF (81). The time delay to trip is plotted as a function
of the measured voltage, for the Exponent = 0, 1, 2, 3, 4 respectively.
)
- +
_ t MinTripDelay _
is the voltage dependent time delay (at constant voltage),
is the measured voltage
is a setting,
are voltage settings corresponding to
0
1
2
3
4
95
V [% of VBase]
en05000075_ansi.vsd
Section 10
Frequency protection
100
(Equation 61)
305