2 Functions
220
7SD5 Manual
C53000-G1176-C169-1
the earth fault protection for any fault type (any distance protection pickup) occurring
within zone Z1, the setting 3102 BLOCK for Dist. = every PICKUP and 3174
BLK for DisZone = in zone Z1 applies.
The earth fault protection must be blocked during single-pole automatic reclose dead
time to avoid pick-up with the false zero sequence values and, if applicable, the neg-
ative sequence values arising during this state (address 3103 BLOCK 1pDeadTim).
A setting of YES (default setting for devices with single-pole tripping) is required if
single-pole automatic reclosure is to be carried out. Otherwise set NO. Setting param-
eter 3103 BLOCK 1pDeadTim to YES completely blocks the earth fault protection if
the Open-Pole Detector has recognized a single-pole dead time. If no single-pole trip-
ping is carried out in the protected network, it is absolutely necessary to set this pa-
rameter to NO.
Regardless of how parameter address 3103 BLOCK 1pDeadTim is set, the earth fault
protection will always be blocked during the single-pole dead time, if it has issued a
trip command itself. This is necessary because otherwise the picked up earth fault pro-
tection cannot drop out if the fault current was caused by load current.
Trip Address 3109 Trip 1pole E/F specifies that the earth fault protection trips single
pole, provided that the faulted phase can be determined with certainty. This address
is only valid for devices that have the option to trip single-pole. If you are using single-
pole automatic reclosure, the setting YES (default setting) remains valid. Otherwise set
NO.
Definite Time
Stages
First of all, the mode for each stage is set: address 3110 Op. mode 3I0>>>, address
3120 Op. mode 3I0>> and address 3130 Op. mode 3I0>. Each stage can be set
to operate Forward (usually towards line), Reverse (usually towards busbar) or
Non-Directional (in both directions). If a single stage is not required, set its mode
to Inactive.
The definite time stages 3I0>>> (address 3111), 3I0>> (address 3121) and 3I0>
(address 3131) can be used for a three-stage definite time overcurrent protection.
They can also be combined with the inverse time stage 3I0p PICKUP (address 3141,
see below). The pick up thresholds should in general be selected such that the most
sensitive stage picks up with the smallest expected earth fault current.
The 3I
0
>> and 3I
0
>>> stages are best suited for fast tripping stages (instantaneous),
as these stages use an abridged filter with shorter response time. On the other hand,
the stages 3I
0
> and 3I
0P
are best suited for very sensitive earth fault detection due to
their effective method of suppressing harmonics.
If no inverse time stage, but rather a fourth definite time stage is required, the „inverse
time“ stage can be implemented as a definite time stage. This must already be taken
regard of during the configuration of the protection functions (refer to Section 2.1.1.3,
address 131 Earth Fault O/C = Definite Time). For this stage, the address
3141 3I0p PICKUP then determines the current pickup threshold and address 3147
Add.T-DELAY the definite time delay.
The values for the time delay settings T 3I0>>> (address 3112), T 3I0>> (address
3122) and T 3I0> (address 3132) are derived from the earth fault grading coordina-
tion diagram of the system.
During the selection of the current and time settings, regard must be taken as to
whether a stage should be direction dependent and whether it uses teleprotection.
Refer also to the margin headings „Determination of Direction“ and „Teleprotection
with Earth Fault Protection“.
www . ElectricalPartManuals . com
To Next Page
Loading...
Need help?
General