ABB Relion Technical Manual page 311

1MRK 502 048-UUS A
Technical manual
æ ö
V
measured
ç ÷
è ø
f
=
measured
=
M
æ ö
VBase
ç ÷
è ø
f
rated
ANSIEQUATION2404 V1 EN
Inverse delays as per figure 140, can be modified (limited) by a special definite delay
setting t_MinTripDelay, see figure 139.
delay in s
t_MaxTrip
Delay
under -
inverse delay law
excitation
overexcitation
0
M=Pickup1
Pickup1
ANSI99001067 V2 EN
Figure 139: Restrictions imposed on inverse delays by
A definite maximum time of 1800 seconds is used to limit the operate time at low degrees
of overexcitation of Pickup1. Inverse delays longer than 1800 seconds will not be allowed.
In case the inverse delay is longer than 1800 seconds, OEXPVPH (24) trips
t_MaxTripDelay, see figure 139.
A definite minimum time t_MinTripDelay, can be used to limit the operate time at high
degrees of overexcitation for Pickup1. In case the inverse delay is shorter than
t_MinTripDelay, OEXPVPH (24) function trips after t_MinTripDelay seconds.
V f
measured rated
×
VBase f
measured
t_MinTripDelay
M – Pickup1
Overexcitation M-Pickup1
max
M
Excitation M
max
E (only if f = fn = const)
E
max
ANSI99001067-2-
en.vsd
Section 9
Voltage protection
(Equation 90)
305