Siemens siprotec SJ62, Руководство пользователя

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2.12 Ground Fault Protection 64, 67N(s), 50N(s), 51N(s)
214
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
When changing to primary values, the following applies:
Motor with the parameterization:
When changing to primary values, the following applies:
With regard to a ground fault in a ungrounded or resonant-grounded system, nearly
the entire displacement voltage appears at the device terminals, therefore the pickup
setting is not critical, and typically lies between 30 V and 60 V (for
64-1 VGND
with a
standard V0-connection) or 50 V and 100 V (for
64-1 VGND
). Large fault resistances
may require higher sensitivity (i.e. a lower pickup setting).
With regard to a grounded system, a more sensitive (lower) pickup value may be set,
but it must be above the maximum anticipated displacement voltage during normal
(unbalanced) system operation.
Trip Time Delay Pickup of just the voltage element may initiate time delayed tripping assuming that
ground fault detection is configured to perform tripping (address
3101 Sens. Gnd
Fault
=
ON
) and moreover address
3130 PU CRITERIA
is configured
Vgnd OR
INs
. The tripping delay is then set at address
3112 64-1 DELAY
. It is important to
note that the total tripping time consists of the displacement voltage measurement
time (about 50 ms) plus the pickup time delay (address
3111 T-DELAY Pickup
) plus
the tripping time delay (address
3112 64-1 DELAY
).
Determination of
Direction Addresses
3115
to
3126
are for direction determination.
The direction of the definite high-set element 67Ns-2 is set at address
3115 67Ns-2
DIRECT
and may be configured
Forward
or
Reverse
or
Non-Directional
, i.e. to
both directions. The direction of the definite time high-set element 67Ns-1 can be set
at address
3122 67Ns-1 DIRECT.
=
Forward
or
Reverse
or
Non-Directional
,
i.e. to both directions.
Current value
RELEASE DIRECT.
(address
3123
) is the release threshold for direc-
tional determination. It is based on the current components which are perpendicular
to the directional limit lines. The position of the directional limit lines themselves are
based on the settings entered at addresses
3124
and
3125
.
The following is generally valid for determination of direction during ground faults: The
pickup current INs dir (=
RELEASE DIRECT.
address
3123
) must be set as high as
possible to avoid a false pickup of the device provoked by asymmetrical currents in
the system and by current transformers (especially in a Holmgreen-connection).
If direction determination is used in conjunction with one of the current elements dis-
cussed above (
50Ns-1 PICKUP
, addresses
3117
ff, or
51Ns PICKUP
, addresses
3119
ff), a value for address
RELEASE DIRECT.
is only significant if it is less than or
equal to the pickup value mentioned above.
A corresponding message (reverse, forward, or undefined) is issued upon direction
determination. To avoid chatter for this message resulting from sharply-varying ground
fault currents, a dropout delay
RESET DELAY
, entered at address
3126
, is initiated
Parameter 213 VT Connect. 3ph = Van, Vbn, Vcn
Parameter 3110 64-1 VGND = 40 V