IG-150-EN version 04; 03/10/16
90
Protection functions. Description and settings
General instructions
ekor.rps
Lockings
The frequency derivative units are locked by:
1. Minimum supervision current. If the minimum current
that flows through the phase A is lower than the setting,
the pickup of the frequency derivative unit’s pickup is
not allowed. When a current higher than the threshold
appears, the relay waits 10 cycles before starting to
execute the frequency gradient function.
2. Minimum supervision voltage. If the voltage in phase
B is lower than the setting, the pickup of the frequency
derivative unit’s pickup is not allowed. When a voltage
higher than the threshold appears, the relay waits 10
cycles before starting to execute the frequency gradient
function.
4.19. Fuse failure
Fuse failure conditions are the following ones:
1. Positive sequence current I
1
above 0.05 % of the full
scale (40 A)
[4]
.
2. Positive sequence current I
1
above 0.1 A.
3. The increase and decrease of the positive sequence
current I
1
and of the neutral current I
r
against the
current measure 2 cycles before must be lower than
0.05 % of the full scale (40 A)
[4]
.
4. The increase and decrease of positive sequence current
I
1
and of the neutral current Ir against the current
measured 2 cycles before must be lower than 0.1 A.
5. Positive sequence voltage V
1
memorized 2 cycles before
must exceed V
FF
.
6. Positive sequence voltage V
1
must be lower than the 95
% of V
FF
.
V
FF
V
N
50
63,5
⋅
:=
(V)
Being Vr the single rated voltage
[4]
The options in bold correspond to the standard ratings.
To activate the fuse failure, this conditions must be kept
during a programmable time (“Additional timing” in console,
“Trip time” in the display (table 0 – protections-fuse failure).
The function is activated until V
1
voltage exceeds V
FF
.
If any function has picked up or during the relay’s waiting
time, any of its protection units picks up, the fuse failure
outputs is not activated because what the relays has
detected is a fault and not a fuse failure situation.
The fuse failure pick up and trip activate if the digital
input “Fuse failure” is activated, independently of the
programmed time. Fuse failure will only deactivate if the
inputs is deactivated.
Fuse failure may be used as a blocking signal for other
functions.
Summary of Contents for ekor.rps
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