Siemens siprotec 7SD5 User Manual page 40

2 Functions
Distance Depending on the ordered version, the distance protection of the 7SD5, if configured
Protection as the main protection function or in combination with differential protection, features
a range of fault detection modes, from which the appropriate type for the particular
system conditions can be selected. If the device is equipped with impedance pickup
only (7SD5***-*****-*E** and 7SD5***-*****-*H**), you can select the tripping charac-
teristic to be used by the distance protection; to do so, set address 115 for phase-
phase measuring units Phase Distance and address 116 for phase-earth measur-
ing units Earth Distance accordingly. You can choose between the polygonal trip-
ping characteristic Quadrilateral and the MHO characteristic MHO. The character-
istics and measurement methods are described in detail in Sections 2.5.2 and 2.5.3.
You can choose different settings for the two addresses. If the device is to used only
for phase-earth loops or only for phase-phase loops, set the function that is not re-
quired to Disabled.
Other pickup procedures are available with the variants 7SD5***-*****-*D** and
7SD5***-*****-*G**. The properties of these procedures are described in detail in
Section 2.5.1.
If the fault current magnitude is a reliable criterion for distinction between a fault oc-
currence and load operation (incl. tolerable overload), set Address 117 Dis. PICKUP
= I> (overcurr.) (overcurrent pickup). If the voltage surge is required as another
pickup criterion, set U/I (voltage-dependent current pickup). For heavily loaded high-
voltage lines and very-high-voltage lines the setting U/I/ϕ (voltage and phase-angle
dependent current pickup) may be required. With setting Z< (quadrilat.) (...
pickup) the distance zones which are set highest establish the pickup criteria. If you
set address 117 Dis. PICKUP to Disabled, the distance protection function and all
associated functions will not be available.
Please note that the power swing supplement (see also Section 2.6) only works to-
gether with the Z< (quadrilat.) pickup. In all other cases it is ineffective, even
though you have set address 120 Power Swing = Enabled.
To complement the distance protection function by teleprotection schemes, you can
select the desired scheme at address 121 Teleprot. Dist.. You can select the
permissive underreach transfer trip with pickup PUTT (Pickup) and with overreach
zone PUTT (Z1B), the teleprotection scheme POTT, directional comparison pickup
Dir.Comp.Pickup, unblocking with Z1B UNBLOCKING, blocking scheme
BLOCKING, and the schemes with pilot wire comparison Pilot wire comp and
Rev. Interlock (reverse interlocking). If you do not want to use teleprotection in
conjunction with distance protection set Disabled.
If use of the setting group changeover function is desired, address 103 Grp Chge
Other Special
OPTION should be set to Enabled. In this case, up to four different groups of settings
Features
may be changed quickly and easily during device operation (see also Section 2.1.3).
With the setting Disabled only one parameter group is available.
Address 110 Trip mode is only valid for devices that trip single-pole or three-pole.
Set 1-/3pole to enable also single-pole tripping i.e., if you want to utilize single-pole
or single-pole / multi-pole automatic reclosure. This requires an internal automatic re-
closing function to be available or an external reclosing device. Furthermore, the
circuit breaker must be capable of single pole tripping.
Note
If you have changed address 110, save your changes first via OK and reopen the
dialog box since the other setting options depend on the selection in address 110.
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7SD5 Manual
C53000-G1176-C169-1