Thytronic NG10 User Manual

FUNCTION CHARACTERISTICS
70
NG10 - Manual - 04 - 2022
Breaker failure - BF
Preface
When the protection issues a trip command but, because an anomaly, the circuit breaker cannot
open, the breaker failure protection issues a back-up trip command to trip adjacent circuit breakers.
The breaker failure function may be started by internal protective function (if associated with BF) or
by external protections.
Operation and settings
The starting of the timer occurs if both the following conditions are filled:
1) Start and trip of internal protective elements (trip of elements matched with BF protection) or, trip
of external protections acquired by means binary input, if enabled;
2) The CB is closed (the CB state may be acquired by means two binary inputs connected to the
auxiliary contacts 52a and 52b or the fundamental component of at least one phase current I
L1
(H),
I
L2
(H), I
L3
(H) is greater than the I I
BF
>. If the information concerning the status of the circuit break-
er is not available (eg, auxiliary contacts are not accessible or unavailability of free logic inputs on
the relay), that control must be disabled.
If both conditions are held along the set operate time t
BF
l, the BF element trips at deadline, vice
versa the timer is cleared and the function is restored.
To the purpose to restore the BF element as quickly as possible, with start of the same protection
(see A condition), additionally to the trip of some internal protections, their starts are required (start
reset is faster than trip reset).
The element may be enabled or disabled by setting ON the BF BF Enable parameter available
inside the Set \ Profile A(or B) \ Breaker failure-BF menu.
BF start from Circuit breaker
If the CBInput parameter (BF Start from circuit breaker) is set to ON, and two binary inputs are
designed for acquire the 52a and 52b auxiliary contacts
[1]
, the control of the CB position is enabled. If
the information concerning the CB position is not available, such control must be disabled by setting
OFF the CBInput parameter. The parameter is available inside the Set \ Profile A(or B) \ Breaker
failure-BF menu, the 52aand52b function must be assigned to the selected binary inputs inside
Set \ Inputs \ Binary input IN1(x) menus (IN1 or INx matching).
To enable the breaker failure protection to operate with trips coming from external protections, one
binary input must be designed to acquire the relative contacts. The TripProtExt function must be
assigned to the selected binary input inside the Set \ Inputs \ Binary input IN1(...) menus (IN1 or IN...
matching).
To enable the breaker failure protection to operate with trips coming from external protections, one
binary input must be designed to acquire the relative contacts. The TripProtExt function must be
assigned to the selected binary input inside the Set \ Inputs \ Binary input IN1(...) menus (IN1 or IN...
matching).
All the I
BF>
, and t
BF
parameters can be set separately for Profile A and Profile B; they are available
inside the Set \ Profile A(or B) \ Breaker failure-BF menu.
Logical block (Block1)
If the BF-BLK1parameter is set to ON, and a binary input is designed for logical block (Block1), the
breaker failure 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.
[2]
The enabling
parameter is available inside the Set \ Profile A(or B) \ Breaker failure-BF, while the Block1 func-
tion must be assigned to the selected binary input inside the Set \ Inputs \ Binary input IN1(x) menus
(IN1 or INx matching).
Note 1 Both auxiliary contact state 52a and 52b must be acquired (two binary inputs are required) with Fw version previous to 1.60; with later versions,
giving up an inconsistency occurs, one logical input for the acquisition of a contact (52nd or 52b ) may suffice
Note 2 The exhaustive treatment of the logic block (Block 1) function may be found in the “Logic Block” paragraph inside CONTROL AND MONITORING
section
all-FBF.ai
General logic diagram of the breaker failure element - BF
Block1
BLK1 BF
I
L1
...I
L3
52b
52a
Trip ProtExt
Start BF
Trip BF
Block1
&
BF-BLK1
BF Enable I
BF
> t
BF

Thytronic NG10 Specifications

General

Brand	Thytronic
Model	NG10
Category	Protection Device
Language	English