Thytronic DMC3S - Page 43

43
DMC3S - Manual - 08 - 2021
The first threshold (I
2
>) can be inhibited by the start of the second threshold (I
2
>>) with the param-
eter deactivation I2> from start I2>> (I2>disbyI2>>) in the menu Set \ Protections \ Negative
sequence overcurrent - 46 \ Threshold I2>> \ Parameters.
A constant reset time can be set for each of the two thresholds (t
2
>
RES
, t
2
>>
RES
).
Shrink time
For each of the two programmed thresholds with definite time characteristic you can set the con-
tracted time by setting to ON the parameter EnTcI2>def and EnTcI2>>def and regulate the
contracted time (tcI2>def and tcI2>>def) and the related operating time (tatcI2>def and
tatcI2>>def).
Once the breaker closes, during the operating time (e.g.: tatcI2>def), the value of the trip time
(e.g.: t2>def ) is replaced by the contracted time (e.g.: tcI2>def ); when the operating time ex-
pires the trip time is reset (e.g.: t2>def ).
The related parameters are available in the menu Set \ Protections \ Negative sequence overcurrent
- 46 \ Threshold I2> (Threshold I2>>) \ Definite time.
Second harmonic restraint
For each threshold, a second harmonic restraint block can be set by setting to ON the parameter
I2>2ndh-REST, I2>>2ndh-REST.
The related parameters are available in the menu Set \ Protections \ Negative sequence overcurrent
- 46 \ Threshold I2> (Threshold I2>>) \ Parameters..
Fun-F46M_S1.ai
t
2>RES
T0
RESET
t
2
>
0T
t
2>inv
t
2>RES
Start I2>
Trip I2>
ON≡Inhibit (from I2>> element)
ON≡Enable I2> overcurrent element
I2> inhibition
&
TRIPPING MATRIX (LED+RELAYS)
I
2
> Curve
0T
I2> Enable
I2>TR-K
I2>TR-L
I2>ST-L
I2>ST-K
I
2
≥ I
2
>
def
I
2
≥ I
2
>
inv
I
2
>
def
I
2
>
inv
I
2
≥1
&
State
&
State
&
EnTcI2>def
“0”
t
2>def
t
CI2>def
t
atcI2
>
def
t
atcI2
>
def
CB control
0 = t
2>def
1 = t
CI2>def
“1”
≥1
Start I
2ndh>
Block1, Block2
&
2nd harmonic restraint enable (ON≡Enable)
I>2ndh-REST
Functional diagram of the rst threshold of the Negative sequence overcurrent protection (46)
CB control
tatcI2>def
tcI2>deft2>def t2>def
BREAKER OPEN
Breaker state
Shrink time enable
Threshold timer
t
BREAKER CLOSED
OFF
Shrink time trip
ON