Thytronic DMC3S - Page 45

45
DMC3S - Manual - 08 - 2021
The first threshold can be set to definite or inverse time with parameter I>Curve (DEFINITE,
NIT, VIT, EIT, LIT) in the menu Set \ Protections \ Overcurrent - 50/51 \ Threshold I> \ Parameters.
The second threshold can be set to definite or inverse time with parameter I>>Curve (DEFI-
NITE, NIT, VIT, EIT, LIT) in the menu Set \ Protections \ Overcurrent - 50/51 \ Threshold
I>> \ Parameters.
The fourth threshold can be set to definite or inverse time with parameter I>>>>Curve (DEFI-
NITE, NIT, VIT, EIT, LIT) in the menu Set \ Protections \ Overcurrent - 50/51 \ Threshold
I>> \ Parameters.
The first threshold I> can be inhibited when at least one of the thresholds I>>, I>>>, I>>>> starts
using the Deactivation I> by start I>>, Deactivation I> by start I>>>, Deactivation I> by start I>>>>
(I>disbyI>>, I>disbyI>>>, I>disbyI>>>>) in the menu Set \ Protections \ Overcurrent
- 50/51 \ Threshold I>>, Threshold I>>>, Threshold I>>>> \ Parameters.
In the same way, the second threshold I>> can be inhibited by the start of thresholds I>>> and I>>>>
by Deactivation I>> by start I>>>, Deactivation I>> by start I>>>> (I>>disbyI>>, I>>dis-
byI>>>, I>>disbyI>>>>) in the menu Set \ Protections \ Overcurrent - 50/51 \ Threshold
I>>>, Threshold I>>>> \ Parameters.
In the same way, the third threshold I>>> can be inhibited by the start of the fourth threshold I>>>
with Deactivation I>> by start I>>> (I>>disbyI>>,) in the menu Set \ Protections \ Overcurrent
-50/51 \ Threshold I>>>> \ Parameters.
A constant reset time can be set for each of the thresholds (t>
RES
, t>>
RES
, t>>>
RES
, t>>>>
RES
).
Shrink time
For each of the thresholds programmed with definite time characteristic, you can select contract-
ed time by setting to ON the parameter EnTcI>def, EnTcI>>def, EnTcI>>>def, En-
TcI>>>>def and adjusting the contracted time (tcI>def, tcI>>def, tcI>>>def,
tcI>>>>def) and operating time (tatcI>def, tatcI>>def, tatcI>>>def, tatcI>>>>-
def). When the breaker closes, during the operating time (e.g.: tatcI>def), the value of the trip time
(e.g.: t>def ) is replaced by the contracted time (e.g.: tcI>def ); when the operating time expires
the trip time is reset (e.g.: t>def ).
The parameters are available in the menu Set \ Protections \ Overcurrent - 50/51 \ Threshold I>
(Threshold I>>, Threshold I>>>, Threshold I>>>>) \ Definite time.
Second harmonic restraint
For each threshold, a second harmonic restraint block can be set by setting to ON the parameter
I>2ndh-REST, I>>2ndh-REST, I>>>2ndh-REST, I>>>>2ndh-REST. The param-
eters are available in the menu Set \ Protections \ Overcurrent - 50/51 \ Threshold I> (Threshold I>>,
Threshold I>>>, Threshold I>>>>) \ Parameters.
Functional block (Block3)
If the amperometric measurement chain fails (function 74CT tripped), all thresholds of protection 51
are blocked.
Fun_50-51S1.ai
I
L1
I
L2
t
>RES
T0
RESET
t
>
0T
≥1
≥1
≥1
t
>inv
t
>RES
Start I>
Trip I>
Start I
2ndh>
ON≡Inhibit (from I>> and/or I>>> overcurrent elements)
ON≡Inhibit (from 74VT element)
ON≡Enable I> overcurrent element
CB control
I> inhibition
74VT inhibition
Block1, Block2
&
&
2nd harmonic restraint enable (ON≡Enable)
I>2ndh-REST
TRIPPING MATRIX (LED+RELAYS)
I> Curve
0T
I
L3
I> Enable
I>TR-K
I>TR-L
I>ST-L
I>ST-K
&
State
I>
inv
I
L1
≥ I>
def
I
L1
≥ I>
inv
I>
def
&
State
&
EnTcI>def
t
>def
t
CI>def
t
atcI
>
def
t
atcI
>
def
CB control
0 = t
>def
1 = t
CI>def
“0”
“1”
Functional diagram of the rst threshold (I>) of the overcurrent function 50/51
tatcI>def
tcI>deft>def t>def
BREAKER OPEN
Breaker state
Shrink time enable
Threshold timer
t
BREAKER CLOSED
OFF
Shrink time trip
ON