Functions
6-103
7SA522 Manual
C53000-G1176-C119-2
The instantaneous tripping following manual closure is blocked as long as the inrush-
stabilization recognizes a rush current. This prevents instantaneous tripping by a
stage which, under normal conditions, is sufficiently delayed during energization of a
transformer.
6.5.2
Applying the Function Parameter Settings
During the configuration of the device functions (refer to Section 5.1, address
(DUWK)DXOW2&
) it was determined which characteristics of the overcurrent time
protection would be available. Depending on the configuration selected there, and the
ordered version of the relay, only those parameters applicable to the available curves
are accessible now.
By means of the parameter
the earth fault protection can
be switched
2Q
or
2II
. This refers to all functions of the earth fault protection.
Each individual stage, if not required, can be
deactivated
(see below).
Blocking
The earth fault protection can be blocked by the distance protection to give preference
to the selective fault clearance by the distance protection over tripping by the earth
fault protection. In setting address
it is determined whether
blocking is done during each fault detection of the distance protection (
HYHU\3LFN
XS
) or only during single-phase fault detection by the distance protection (
VLQJOH
SKDVH3LFNXS
) or only during multiple-phase fault detection by the distance protec-
tion (
PXOWLSKDVH3LFNXS
). If blocking is not required, the setting
1R
is applied.
The earth fault protection should be blocked during single-pole automatic reclose
dead time, to avoid pick-up with the false zero sequence values arising during this
state (address
). A setting of
<HV
is therefore only required
if single-pole tripping is implemented. Otherwise the setting
1R
(presetting) remains.
Definite Time
Stages
First of all, the mode for each stage is set:
(address
) ,
(address
) and
(address
). Each stag-
es can be set to operate
forward
(usually towards line) or
reverse direction
(usually
towards busbar) or
non-directional
(in both directions). If a single stage is not re-
quired, set its mode to
deactivated
.
The definite time stages
(address
),
(address
(address
) can be used for a three-stage definite time overcurrent protection.
They can also be combined with the inverse time stage
(address
,
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
>> und 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
are the stages 3I0> and 3I0p best suited for very sensitive earth fault detection. High-
class digital filters are used to suppress the 2
nd
and all higher 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 5.1,
address
(DUWK)DXOW2&
=
'HILQLWH7LPH
). For this stage, the address
Summary of Contents for siprotec 7SA522
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