7SR210 & 7SR220 Description of Operation
Unrestricted ©2018 Siemens Protection Devices Limited
Page 41 of 94
3.5.3
Time Delayed Sensitive Earth Fault Protection (51SEF)
Two time delayed sensitive earth fault elements are provided in the 7SR21 relay. Four elements are provided in
the 7SR22 relay e.g. giving the option of using two elements set to forward and two to reverse.
51SEF-n Setting
sets the pick-up current level.
A number of shaped characteristics are provided. An inverse definite minimum time (IDMT) characteristic is
selected from IEC and ANSI curves using
51SEF-n Char
. A time multiplier is applied to the characteristic curves
using the
51SEF-n Time Mult
setting. Alternatively, a definite time lag (DTL) can be chosen using
51SEF-n Char
.
When DTL is selected the time multiplier is not applied and the
51SEF-n Delay (DTL)
setting is used instead.
The
51SEF-n Reset
setting can apply a
definite time delayed
reset
,
or when configured as an ANSI
characteristic an
ANSI (DECAYING)
reset. If ANSI (DECAYING) reset is selected for an IEC characteristic, the
reset will be instantaneous. The reset mode is significant where the characteristic has reset before issuing a trip
output – see ‘Applications Guide’.
A minimum operate time for the characteristic can be set using
51SEF-n Min. Operate Time
setting.
A fixed additional operate time can be added to the characteristic using
51SEF-n Follower DTL
setting.
Where directional elements are present the direction of operation can be set using
51SEF-n Dir. Control
setting.
Directional logic is provided independently for each 51SEF-n element.
Operation of the time delayed earth fault elements can be inhibited from: -
Inhibit 51SEF-n
A binary or virtual input, function key or remote data Comms
79 SEF Inst Trips:
51SEF-n
When ‘delayed’ trips only are allowed in the auto-reclose sequence
(
79 SEF Prot’n Trip n
=
Delayed
).
51SEF-n VTSAction:
Inhibit
Operation of the VT Supervision function (7SR22).
Directional elements will not operate unless the zero sequence voltage (V
0
) is above the
67SEF Minimum
Voltage
setting i.e. the residual voltage is greater than 3 times this setting and the phase is in the
Forward/Reverse operating range. If
67SEF Wattmetric
is set to Enabled, the calculated residual real power
must be above the
67SEF Wattmetric Power
setting. The residual power P
res
is equal to the wattmetric
component of 3V
0
I
SEF
and therefore the wattmetric component of 9V
0
I
0
Summary of Contents for Argus 7SR21
Page 1: ...Energy Management 7SR21 7SR22 Argus Overcurrent Relay Reyrolle Protection Devices ...
Page 2: ......
Page 4: ...Contents 7SR11 and 7SR12 Page 2 of 2 2018 Siemens Protection Devices Limited ...
Page 185: ...7SR210 Settings Guide Unrestricted 2018 Siemens Protection Devices Limited Page 61 of 61 ...
Page 277: ...7SR220 Settings Guide Unrestricted Page 72 of 107 2013 Siemens Protection Devices Limited ...
Page 382: ...7SR220 Technical Manual Chapter 4 Page 2 of 96 2017 Siemens Protection Devices Limited ...
Page 386: ...7SR220 Technical Manual Chapter 4 Page 6 of 96 2017 Siemens Protection Devices Limited ...
Page 398: ...7SR220 Technical Manual Chapter 4 Page 18 of 96 2017 Siemens Protection Devices Limited ...
Page 414: ...7SR220 Technical Manual Chapter 4 Page 34 of 96 2017 Siemens Protection Devices Limited ...
Page 466: ...7SR220 Technical Manual Chapter 4 Page 86 of 96 2017 Siemens Protection Devices Limited ...
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