Thytronic DMC3S, Manual

Page: 43 / 110

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
T 0
RESET
t
2
>
0 T
t
2>inv
t
2>RES
Start I2>
Trip I2>
ON
≡
Inhibit (from I2>> element)
ON ≡ Enable I2> overcurrent element
I2> inhibition
&
TR
IP
PI
NG M
AT
RI
X
(LE
D+R
EL
AY
S)
I
2
> Curve
0 T
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 first threshold of the Negative sequence overcurrent protection (46)
CB control
tatcI2>def
tcI2>def t2>def t2>def
BREAKER OPEN
Breaker state
Shrink time enable
Threshold timer
t
BREAKER CLOSED
OFF
Shrink time trip
ON