116
116
NC20 - Manual - 01 - 2015
FUNCTION CHARACTERISTICS
To enable the selectivity logic input for a generic xx element, the
xxBLK2IN
parameters must be
set to
ON
inside the
Set \ Parametri di confi gurazione A (o B) \ xxx \ Setpoints
menus concerning all
element where the selective block is available, eg:
I>BLK2IN
inside the
Set \ Profi le A(or B) \ Phase overcurrent-50/51 \
I> Element
\ Setpoints
menu.
Output selective block
Use of output relays
If the
xxBLK2OUT, xxBLK2OUT
and/or
xxBLK2OUT
enable parameters are set to
ON
and a
output relay is designed for selective block (Block2), the protection issues a block output by phase
elements (BLK2OUT-Iph), by ground elements (BLK2OUT-IE) or by any protection element (BLK2OUT-
Iph/IE), whenever the given start is active.
The
BLK2OUT-Iph-K, BLK2OUT-Iph/IE-K
and/or
BLK2OUT-IE-K
output relays must be set in-
side the
Set \ Profi le A(or B) \ Selective block-BLOCK2 \ Selective block OUT
menu; the same for ad-
dressing the LED indicators (
BLK2OUT2-Iph-L, BLK2OUT2-IE-L
and
BLK2OUT2-Iph/IE_L
).
When output relays are programmed for selective block output, the
t
TR
time delays must reset to
zero; the operation mode must be set with self reset (
No-latched
inside
Set \ Relays
submenu) and
the
Logic
parameters (
Energized
/
De-energized
) must be programmed in the same way of the
related binary input connected with-it.
Use of committed pilot wire output BLOUT1
The output is a dry static relay.
The information about phase (
ON IPh
), earth (
ON IE
), or phase+earth (
ON IPh/IE
) concerning the
sending block out signal may be select by means of the
ModeBLOUT1
parameter inside the
Set \
Profi le A(or B) \ Selective block-BLOCK2 \ Selective block OUT
menu.
The parameters can be set separately for
A
and
B
profi les.
Operation
The selective block outputs go ON at the same time of the xx element start; they hold steady (even
if the start reset to zero) for along the
t
F-IPh
,
t
F-IE
and
t
F-IPh/IE
adjustable times for phase, earth and
phase+earth functions.
The timers starts when one or more selective block function goes ON; when a timer expires, the
selective block outputs are disregarded (even if the start holds steady).
The
t
F-IPh
and
t
F-IE
counters start when the output selective block becomes active. When the coun-
ters expire the block selective output is forced off (despite the start xxx remain active).
If the
t
F-IPh
,
t
F-IE
e
t
F-IPh/IE
timers are cleared the selective block output state is freeze up to the start
xxx remain active.
With a setting other than 0.00 s, the
t
F-IPh
,
t
F-IE
e
t
F-IPh/IE
timers may be used to provide a backup
protection against breaker failure inside a selectivity logic system, as well as to hold blocked up-
stream protective relays up after the fault is cleared with CB opening to provide solution against
unwanted trips because of a larger reset time compared with the downstream relay (the selectivity
will be lost).
TB-timer.ai
t
t
B-Iph
/
t
B-IE
BLIN2IN-Iph/BLIN2IN-IE
tB timeout
INPUT BLOCK
(binary input and/or BLIN1)
tB timer
TF-timer.ai
t
t
F-IPh,
t
F-IE,
t
F-IPh/IE
t
F-IPh,
t
F-IE,
t
F-IPh/IE
Start xx
(internal elements)
tF timers
BLK2OUT-Iph
BLK2OUT-IE
BLK2OUT-Iph/IE
