Thytronic DMC3S - Page 49

49
DMC3S - Manual - 08 - 2021
Shrink time
For each of the programmed thresholds with definite time characteristic you can set the contracted
time by setting to ON the parameter EnTcINe>def, EnTcINe>>def and regulating the con-
tracted time (tcINe>def, tcINe>>def) and operating time (tatcINe>def, tatcINe>>def).
Once the breaker closes, during the operating time (e.g.: tatcINe>def), the value of the trip time
(e.g.: tNe>def ) is replaced by the contracted time (e.g.: tcINe>def ); when the operating time
expires the trip time is reset (e.g.: tNe>def ).
The related parameters are available in the menu Set \ Protections \ Neutral overcurrent - 51N(E) \
Threshold INe> (Threshold INe>>) \ Definite time.
Second harmonic restraint
For each of the thresholds (I
Ne
>, I
Ne
>>) you can set a second harmonic restraint block by setting to
ON the parameter INe>2ndh-REST, INe>>2ndh-REST.
The related parameters are available in the menu Set \ Configuration parameters A(or B) \ Neutral
overcurrent - 51N(E) \ Threshold INe> (Threshold INe>>) \ Parameters.
Fun_50N-51N(E).ai
t
Ne>RES
T0
RESET
t
Ne>
0T
≥1
t
Ne>inv
t
Ne>RES
Start INe>
Trip INe>
Start I
2ndh>
ON≡Inhibit
(from INe>> element)
ON≡Enable IE> residual overcurrent element
INe> inhibition
Block1, Block2
&
&
2nd harmonic restraint enable (ON≡Enable)
INe>2ndh-REST
TRIPPING MATRIX (LED+RELAYS)
I
Ne
> Curve
0T
INe> Enable
I
Ne
>TR-K
I
Ne
>TR-L
I
Ne
>ST-L
I
Ne
>ST-K
I
E
≥1
&
State
I
Ne
>
inv
I
E
≥ I
Ne
>
def
I
E
≥ I
Ne
>
inv
I
Ne
>
def
&
State
&
EnTcINe>def
t
Ne>def
t
CINe>def
t
atcIE
>
def
t
atcINe
>
def
CB control
0 = t
E>def
1 = t
CIE>def
“0”
“1”
CB control
tatcINe>def
tcINe>deftNe>def tNe>def
BREAKER OPEN
Breaker state
Shrink time enable
Threshold timer
t
BREAKER CLOSED
OFF
Shrink time trip
ON
Functional diagram of the rst threshold of the neutral overcurrent function 51N(E)