Functions
2.6 Voltage Protection 27, 59
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
146
2.6.4
Setting Notes
General
Voltage protection is only effective and accessible if address
150
27/59
is set to
Enabled
during configuration
of protection functions. If this function is not required, then
Disabled
is set.
The voltage to be evaluated is selected in
Power System Data 1
(see Chapter 2.6, Table 2-11).
Overvoltage protection can be turned
ON
or
OFF
, or set to
Alarm Only
at address
5001
FCT 59
.
Undervoltage protection can be turned
ON
or
OFF
or set to
Alarm Only
at address
5101
FCT 27
.
With the protection functions activated (
ON
), tripping, the opening of a fault and fault recording are initiated
when the thresholds are exceeded and the set time delays have expired.
With setting
Alarm Only
no trip command is given, no fault is recorded and no spontaneous fault annunciation
is shown on the display.
Overvoltage Protection with Phase-to-phase or Phase-to-ground Voltages
The largest of the applied voltages is evaluated for the phase-to-phase or phase-to-ground overvoltage protec-
tion.
The threshold values are set in the value to be evaluated (see Chapter 2.6, Table 2-11).
The overvoltage protection has two elements. The pickup value of the lower threshold (address
5002
or
5003
,
59-1 PICKUP
, depending on the phase-to-ground or the phase-to-phase voltages, can be assigned a longer
time delay (address
5004
,
59-1 DELAY
) and the upper threshold element (address
5005
or
5006
,
59-2
PICKUP
) a shorter (address
5007
,
59-2 DELAY
) time delay. There are no specific procedures on how the
pickup values are set. However, as the function is mainly used to prevent high insulation damage to system
components and users, the threshold value
5002
,
5003
59-1 PICKUP
lies generally between 110 % and
115 % of the nominal voltage and setting value
5005
,
5006
59-2 PICKUP
at approximately 130 %.
The time delays of the overvoltage elements are entered at addresses
5004
59-1 DELAY
and
5007
59-2
DELAY
, and should be selected in such manner that they make allowance for brief voltage peaks that are gen-
erated during switching operations and also enable clearance of stationary overvoltages in due time.
The choice between phase-to-ground and phase-to-phase voltage allows voltage asymmetries (e.g. caused by
a ground fault) to be taken into account (phase-to-ground) or to remain unconsidered (phase-to-phase) during
evaluation.
Note
During configuration of a single-phase voltage transformer connection (parameter
240
VT Connect. 1ph
not
equal to
NO
), parameters
213
VT Connect. 3ph
and
614
OP. QUANTITY 59
are not evaluated. In this
case, exclusively parameters
5003
59-1 PICKUP
or
5006
59-2 PICKUP
are relevant for the threshold values
of the overvoltage protection.
Overvoltage Protection - Positive Sequence System V1
In a three-phase voltage transformer connection the positive sequence system can be evaluated for the over-
voltage protection by means of configuring parameter
614
OP. QUANTITY 59
to
V1
. In this case, the threshold
values of the overvoltage protection must be set in parameters
5019
59-1 PICKUP V1
or
5020
59-2
PICKUP V1
.
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