Thytronic DMC3S - Page 68

68
DMC3S - Manual - 08 - 2021
With detection criterion in “modulus mode”, if the protection is switched to non-directional by the
start of function 74VT, the start (START) of any threshold of protection 67N occurs when the following
condition is satisfied:
- Value of the residual current (I
E
) greater than the amperometric threshold (I
ED>
, I
ED>>
, I
ED>>>
, I
ED>>>>
).
The parameters Mode67N (operating mode), Type67N (residual voltage measurement type),
Insens-Zone (insensitivity zone), M (threshold multiplier for insensitivity zone), 74VTint67N
(operation with internal 74VT) and 74VText67N (operation with external 74VT), common to all
thresholds, can be set in the menu: Set \ Protections \ Ground directional overcurrent - 67N \ Com-
mon configurations.
Projection
With detection criterion in “projection mode”, the start (START) of any threshold of protection 67N
occurs when the following condition C) obtains:
C) With “Insens-Zone=OFF”:
- Projection of the residual current (I
E
) along the characteristic axis > 0
AND
- Value of the projection of the residual current (I
E
) along the characteristic axis greater than the
amperometric threshold (I
ED>
, I
ED>>
, I
ED>>>
, I
ED>>>>
)
AND
- Value of the residual voltage (U
E
or U
EC
) greater than the corresponding voltmetric threshold (U
ED>
,
U
ED>>
, U
ED>>>
, U
ED>>>>
)
AND
The residual current (I
E
) phasor is included in the angular sector with half-amplitude corresponding
to the regulation of the threshold with bisector the characteristic semi-axis of the threshold.
[1]
With “Insens-Zone=ON”:
- Projection of the residual current (I
E
) along the characteristic axis > 0
AND
- Value of the projection of the residual current (I
E
) along the characteristic axis greater than the
amperometric threshold (I
ED>
, I
ED>>
, I
ED>>>
, I
ED>>>>
)
AND
- Value of the residual voltage (U
E
or U
EC
) greater than the corresponding voltmetric threshold
(M∙U
ED>
, M∙U
ED>>
, M∙U
ED>>>
, M∙U
ED>>>>
)
OR
- Value of the projection of the residual current (I
E
) along the characteristic axis greater than the
amperometric threshold (M∙I
ED>
, M∙I
ED>>
, M∙I
ED>>>
, M∙I
ED>>>>
)
AND
- Value of the residual voltage (U
E
or U
EC
) greater than the corresponding voltmetric threshold (U
ED>
,
U
ED>>
, U
ED>>>
, U
ED>>>>
)
AND
The residual current (I
E
) phasor is included in the angular sector with half-amplitude corresponding
to the regulation of the threshold with bisector the characteristic semi-axis of the threshold.
[2]
Each threshold of the protection can be enabled or disabled by setting to ON or OFF the parameter
IED> Enable, IED>> Enable, , IED>>> Enable and/or IED>>>> Enable in the menu
Set \ Protections \ Ground directional overcurrent - 67N \ Threshold IED> (Threshold IED>>, Thresh-
old IED>>>, Threshold IED>>>>) \ Parameters.
The first two thresholds can be set to definite or inverse time with the parameter IED>Curve and/
or IED>Curve (DEFINITE, IEC/BS A, IEC/BS B, IEC/BS C, ANSI/IEE MI, ANSI/
IEE VI, ANSI/IEE EI, EM) in the menus Set \ Protections \ Ground directional overcurrent -
67N \ Threshold IED> \ Parameters and Set \ Configuration parameters A(or B) \ Ground directional
overcurrent - 67N \ Threshold IED>> \ Parameters.
The first threshold IED> can be inhibited when at least one of the three thresholds IED>>, IED>>>,
IED>>>> starts using the Deactivation IED> by start IED>>, Deactivation IED> by start IED>>>, De-
activation IED> by start IED>>>> (IED>disbyIED>>, IED>disbyIED>>>, IED>disb-
yIED>>>>) in the menu Set \ Protections \ Ground directional overcurrent - 67N \ Threshold
IED>>, Threshold IED>>>, Threshold IED>>>> \ Parameters.
The same applies to the inhibition of:
• Second threshold IED>> by the start of at least one of IED>>>, IED>>>> with the Deactivation IED>>
by start IED>>>, Deactivation IED>> by start IED>>>> parameters (IED>>disbyIED>>>,
IED>>disIED>>>>) in the menu Set \ Protections \ Ground directional overcurrent - 67N \
Threshold IED>>>, Threshold IED67N.sb \ Parameters.
Note 1 The projection of the residual current phasor along the characteristic axis of each threshold is given by I
E
cos(ϑ
E
>-Φ
E
), I
E
cos(ϑ
E
>>-Φ
E
), I
E-
cos(ϑ
E
>>>-Φ
E
), I
E
cos(ϑ
E
>>>>-Φ
E
) for “direct residual voltage”, or:
I
E
cos(ϑ
E
>-Φ
EC
), I
E
cos(ϑ
E
>>-Φ
EC
), I
E
cos(ϑ
E
>>>-Φ
EC
), I
E
cos(ϑ
E
>>>>-Φ
EC
) for “calculated residual voltage”.
The symbols ϑ
E
and Φ
EC
are not available in the Thysetter and MMI menus
Note 2 The projection of the residual current phasor along the characteristic axis of each threshold is given by I
E
cos(ϑ
E
>-Φ
E
), I
E
cos(ϑ
E
>>-Φ
E
), I
E-
cos(ϑ
E
>>>-Φ
E
), I
E
cos(ϑ
E
>>>>-Φ
E
) for “direct residual voltage”, or:
I
E
cos(ϑ
E
>-Φ
EC
), I
E
cos(ϑ
E
>>-Φ
EC
), I
E
cos(ϑ
E
>>>-Φ
EC
), I
E
cos(ϑ
E
>>>>-Φ
EC
) for “calculated residual voltage”.
The symbols ϑ
E
and Φ
EC
are not available in the Thysetter and MMI menus