22
TB MRF3 04.01 E
5.10
Dynamic behaviour of the relay
functions
The following table shows the dynamic behaviour of
the relay functions under various system conditions.
System condition /
Function
event
f>
f<
df/dt for
load shedding
df/dt for
mains decoupling
Applying auxiliary voltage
active after 1 s
active after 1 s
active after 1 s
active after 1 s
Applying auxiliary voltage
to the external blocking in-
put
not blocked*
Blocked*
Blocked*
Blocked*
Disconneting the auxiliary
voltage from the external
blocking input
no influence
active after 1.5 s
active after 1.5 s
active after 1.5 s
Applying auxiliary voltage
to the external reset input
reset of the relay
(Display)
reset of the relay
(Display)
reset of the relay
(Display)
reset of the relay
(Display)
Applying the system volt-
age to the frequency
measuring input
active after 1.5 s
active after 1.5 s
active after 1.5 s
active after 1.5 s
Applying a voltage <U
B
to
the frequency measuring
input
blocked
blocked
blocked
blocked
Applying a voltage with a
frequency <f
e
to the fre-
quency measuring input
active after 1.5 s
active after 1.5 s
no tripping
no tripping
Disconnecting system volt-
age from the frequency
measuring input
blocked
blocked
blocked
blocked
Voltage drops below U
B-
min
blocked
blocked
blocked
blocked
Recovering of system
voltage U
B
max
active after 1.5 s
active after 1.5 s
active after 1.5 s
active after 1.5 s
Voltage vector surge
no tripping
no tripping
no tripping
no tripping
Short time voltage drop
no tripping
no tripping
no tripping
no tripping
Table 5.5: Dynamic behaviour of
MRF3
-Functions
* There is a free choice of parameters for the setting (see chapter 5.7.1).
Summary of Contents for MRF3
Page 1: ...MRF3 Frequency Relay...