•
79 GS Triggers allows 50Gs and 51Gs sensitive earth fault elements to be selected as autoreclose triggers
•
79 Extern Triggers allows trip signals from external protection relays to be connected to binary inputs to
start autoreclose. Similarly other internal protection elements to be selected as autoreclose triggers by
mapping to the 79 ExtTrip input via user logic.
In the 79 settings, each autoreclose attempt (autoreclose shot) is defined as being either a normal delayed trip
or an inst trip. This setting controls the ungraded instantaneous protection elements which are used in
advanced schemes.
The 79 Delayed Inhibit setting within each overcurrent and earth fault element is then used to define
whether each element is in service or automatically disabled during a sequence. During a delayed shot, all
protection elements that are designated as inst are inhibited. During an inst shot, all elements are active and
no inhibits are applied. For simple autoreclose sequences this advanced functionality is not required and all
shots should be set to inst and or all elements should be set to delayed. Care should be taken if any elements
are set to both inst and delayed as incorrect setting can result in no protection being in service. Inst protection
elements are not automatically inhibited when autoreclose is switched out, if this common arrangement is
required it must be configured in user logic. Inst elements are not automatically inhibited when autoreclose is
disabled. If autoreclose is disabled, elements should not be configured as type inst.
[dw_7SR5_function79SettingExample, 1, en_US]
Interfacing Automatic Reclosing Function with External Protection Devices
Autoreclose can be initiated from another protection device via a binary input connection or other input such
as IEC 61850 goose. Logic can also be configured to use the 79 Extern autoreclose sequence for internal
protection functions which are not included in the standard autoreclose fault types such as voltage, frequency
and un-balance protections. The 79 element provides a blocking signal which can be configured for each shot
in the sequence such as 79 Extern Prot’n Trip 1 which can be used to inhibit the external device trip-
ping such as if it is an instantaneous type device which should not operate when the sequence has reached a
delayed shot. In addition, the sequence will not start or continue if the Extern Trigger input is raised on a
shot where the Extern Block is raised. The maximum number of shots is controlled by the 79 Num Shots
setting but can also be limited by the 79 Extern Trips to LO setting.
Control Functions
7.3 79 Automatic Reclosing
432 Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019
To Next Page
Loading...
