Thytronic DMC3S, Руководство пользователя

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62
DMC3S - Manual - 08 - 2021
When projection mode detection and two of three - 2/3 trip logic are selected, the start (START) of
any threshold of protection 67 occurs when one of the following two conditions is satisfied:
• the projection of the current phasor for at least one pair of phases along the characteristic axis
I
Lx
cos( θ >- α
x
), I
Lx
cos( θ >>- α
x
), I
Lx
cos( θ >>>- α
x
), I
Lx
cos( θ >- α
x
) (x=1 and 2, 2 and 3, 3 and 1) is positive
and violates the threshold ( I
PD>
, I
PD>>
, I
PD>>>
, I
PD>>>>
).
• In at least one pair of phases the fundamental component of the current ( I
L1
e I
L2
, I
L2
e I
L3
, I
L3
e I
L1
)
violates the threshold ( I
PD>
, I
PD>>
, I
PD>>>
, I
PD>>>>
).
When the threshold starts, so does its timer.
If for the entire operating time of the threshold ( t
PD>
, t
PD>>
, t
PD>>>
, t
PD>>>>
) the above condition per-
sists, when the time expires the threshold trips (TRIP), otherwise it resets.
Each threshold of the protection can be enabled or disabled by setting to
ON
or
OFF
the parameter
IPD> Enable
,
IPD>> Enable,
,
IPD>>> Enable
and/or
IPD>>>> Enable
in the menu
Set \ Protections \ Maximum directional current - 67 \ Threshold IPD> ( Threshold IPD>> , Threshold
IPD>>> , Threshold IPD>>>>) \ Parameters .
The first two thresholds can be set to definite or inverse time with the parameter
IPD>Curve
and/or
IPD>>Curve
(
IDEFINITE, NIT, VIT, EIT, LIT
) in the menus Set \ Protections \
Maximum directional current - 67 \ Threshold IPD> \ Parameters and Set \ Protections \ maximum
directional current - 67 \ Threshold IPD>>\ Parameters .
The first threshold IPD> can be inhibited when at least one of the three thresholds IPD>>, IPD>>>,
IPD>>>> starts using the Deactivation IPD> by start IPD>>, Deactivation IPD> by start IPD>>>,
Deactivation IPD> by start IPD>>>> ( IPD>disbyIPD>>, IPD>disbyIPD>>>, IP-
D>disIPD>>>> ) in the menu
Set \ Protections \ Overcurrent - 67 \ Threshold IPD>>
,
Threshold
IPD>>>
,
Threshold IPD>>>> \ Parameters.
The same applies to the inhibition of:
• Second threshold IPD>> by the start of at least one of IPD>>>, IPD>>>> with the Deactivation IPD>>
by start IPD>>>, Deactivation IPD>> by start IPD>>>> parameters ( IPD>>disbyIPD>>>, IP-
D>>disIPD>>>> ) in the menu
Set \ Protections \ Maximum directional current - 67 \ Thresh-
old IPD>>>
,
Threshold IPD>>>> \ Parameters.
• Third threshold IPD>>> by the start of the fourth threshold IPD>>>> with the Deactivation IPD>>>
by start IPD>>>> parameter ( IPD>>>disIPD>>>> ) in the menu
Set \ Protections \ Maximum
directional current - 67 \ Threshold IPD>>>> \ Parameters.
Shrink time
For each of the thresholds programmed with definite time characteristic, you can select contracted
time by setting to ON the parameter EnTcIPD>def , EnTcIPD>>def , EnTcIPD>>>def e
EnTcIPD>>>>def and regulating the contracted time ( tcIPD>def , tcIPD>>def , tcIP-
D>>>def e tcIPD>>>>def ) and operating time ( tatcIPD>def , tatcIPD>>def , tatcIP-
D>>>def e tatcIPD>>>>def ).
Once the breaker closes, during the operating time (e.g.: tatcIPD>def ), the value of the trip time
(e.g.: tPD>def ) is replaced by the contracted time (e.g.: tcIPD>def ); when the operating time
expires the trip time is reset (e.g.: tPD>def ).
The parameters are available in the menu
Set \ Protections \ Overcurrent - 67 \ Threshold IPD>
(
Threshold IPD>>, Threshold IPD>>>, Threshold IPD>>>>) \ Definite time
.
Second harmonic restraint
For each threshold, a second harmonic restraint block can be set by setting to ON the parameter IP-
D>2ndh-REST, IPD>>2ndh-REST, IPD>>>2ndh-REST, IPD>>>>2ndh-REST .
The parameters are available in the menu
Set \ Protections \ Overcurrent - 67 \ Threshold IPD>
(
Threshold IPD>>, Threshold IPD>>>,Threshold IPD>>>>) \ Parameters.
Functional block (Block3)
If the voltmetric measurement chain fails (function 74VT tripped) or amperometric measurement
chain fails (function 74CT tripped), all thresholds of protection 67 are blocked.