74
74
NV10P - Manual - 01 - 2015
CHARACTERISTICS
The underfrequency protection is enabled only when the maximum of the input voltages
U
LMAX
=max(U
L1
, U
L2
, U
L3
) overcomes 0.2 U
n
for a tfEN adjustable time.
Setting of the tfEN value is available inside the Set \ Base menu with “level 1” session.
The trip of f< element may be inhibited by the start of the second, third and/or fourth element (f<<,
f<<<, f<<<<) by setting ON the Disable f< by start f<<, Disable f< by start f<<<, Disable f< by start
f<<<< (f<disbyf<<, f<disbyf<<<, f<disbyf<<<<) parameters available inside the Set \ Pro-
fi le A(or B) \ Underfrequency-81U \ f<< Element (f<<< Element,f<<<< Element) \ Setpoints menus.
Similarly the trip of the:
f<< element may be inhibited by start of the third and/or fourth element (f<<< and/or f<<<<) by setting
ON the Disable f<< by start f<<<, start f<<<< (f<<disbyf<<<, f<<disbyf<<<<) parameter avail-
able inside the Set \ Profi le A(or B) \ Underfrequency-81U \ f<<< Element, (f<<<< Element) \ Setpoints
menus.
f<<< element may be inhibited by start of the fourth element (f<<<<) by setting ON the Disable f<<<
by start f<<<< (f<<<disbyf<<<<) parameter available inside the Set \ Profi le A(or B) \ Under-
frequency-81U \ f<<<< Element \ Setpoints menu.
The elements can be disabled in the case of connection of the measuring inputs (TV or TV-I-NI) down-
stream of the Device Interface when the DI is open. The threshold disabling is selected by setting ON
the f<disbyCB_OPEN, f<<disbyCB_OPEN, f<<<disbyCB_OPEN, f<<<<disbyCB_OPEN
parameters, inside theSet \ Profi le A(or B) \ Underfrequency-81U \ Setpoints menu.
When the CB closes, the operate time of the f<< element is automatically adjusted to a reduced value
tcf<<def for an adjustable time tatcf<<def. The reduction of the operate time for the second
threshold can be selected by setting the EnTcf<<def parameter inside the Set \Profi le A(or B) \
Underfrequency-81U \ f<< Element \ Setpoints menu, while the timers are adjustable inside the Set
\Profi le A(or B) \ Underfrequency-81U \ f<< Element \ Defi nite time menu
Logical block (Block1)
If the f<BLK1, f<<BLK1, f<<<BLK1 and/or f<<<<BLK1 enabling parameters are set to ON
and a binary input is designed for logical block (Block1), the protection is blocked off whenever the
given input is active.
The trip timer is held in reset condition, so the operate time counting starts when the input block
goes down.
[1]
The enabling parameters are available inside the Set \ Profi le A(or B) \ Underfrequency
- 81U \ f< Element (f<< Element, f<<< Element, f<<<< Element) \ Setpoints menus, while the Block1
function must be assigned to the selected binary input inside the Set \ Inputs \ Binary input IN1(x)
menus (IN1 or INx matching).
Note 1 The exhaustive treatment of the logical block (Block 1) function may be found in the “Logic Block” paragraph inside CONTROL AND MONITOR-
ING section.
•
•
Timers-F81.ai
t
dfEN
81O-81U Enable
81O-81U disabled 81O-81U disabled81O-81U enabled
0.20 U
n
Max (U
L1
...U
L3
)
t
Overfrequency & underfrequency enable timer
Timers-F81.ai
t
dfEN
81O-81U Enable
81O-81U disabled 81O-81U disabled81O-81U enabled
0.20 U
n
Max (U
L1
...U
L3
)
t
Overfrequency & underfrequency enable timer
Logic diagram concerning the first threshold (f<) of the underfrequency element - 81U
Fun-F81U_S1.ai
RESET
t
f<def
0T
TRIPPING MATRIX
(LED+RELAYS)
f<
Start
f<
Start
f<
Trip
f<
Trip
Block1
&
&
&
Enable (ON≡Enable)
Block1 input (ON≡Block)
f<
Block1
Block1
Binary input INx
T0
Logic
INx
t
ON
INx
t
ON
INx
t
OFF
T0
n.o.
n.c.
INx
t
OFF
t
f<def
f<
ST-K
f<
ST-L
f<
TR-K
f<
TR-L
f<
Trip
BF Enable (ON≡Enable)
towards BF logic
&
f<
BF
f<BF
f<BLK1
f<
inhibition
(ON≡
Inhibit
)
&
f
<
f
<
def
f
<
def
U
L1
,U
L2
,U
L3
Max(U
L1...
U
L3
) ≥20%U
n
≥1
(1≡DDI closed)
DDI state
(1≡upstream)
f<disbyCB_OPEN
Min(f
UL1,
f
UL2,
f
UL3
)f
UL1,
f
UL2,
f
UL3
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