204
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
GROUPED PROTECTION ELEMENTS
CHAPTER 7: PROTECTION
This setting should be at least three times the
Current Cutoff Level
setting specified in
the
Settings > Protection > Power System > AC Inputs - Current
menu. Zone 1 is sealed
in with the current supervision.
Voltage Level
Range: 0.000 to 5.000 pu in steps of 0.001
Default: 0.000 pu
This setting is relevant for applications on series-compensated lines, or in general, if
series capacitors are located between the relaying point and a point for which the zone
shall not overreach. For plain (non-compensated) lines, this setting shall be set to zero.
Otherwise, the setting is entered in per unit of the VT bank configured under the distance
Source
setting. Effectively, this setting facilitates dynamic current-based reach
reduction. In non-directional applications, this setting applies only to the forward reach
of the non-directional zone.
NOTE
NOTE:
The use of dynamic reach control by selection of a non-zero value for the
Voltage Level
setting will disable the subcycle operating time for that particular zone.
Delay
Range: 0.000 to 65.535 seconds in steps of 0.001
Default: 0.000 seconds
This setting enables the user to delay operation of the distance elements and implement
a stepped distance backup protection. The distance element timer applies a short drop
out delay to cope with faults located close to the boundary of the zone when small
oscillations in the voltages and/or currents could inadvertently reset the timer.
Block
Range: any FlexLogic™ operand
Default: Off
This setting enables the user to select a FlexLogic™ operand to block the given ground
distance element. VT fuse fail detection is one of the applications for this setting.
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of ground distance events in the sequence
of events recorder.
The ground distance operation scheme for zone 1 is shown below.
Figure 179: Ground distance zone 1 operation scheme logic
The ground distance operation scheme for zone 2 is shown below. The logic is analogous
for zones 3 through 5.
$&'5
$1'
25
$1'
)/(;/2*,&23(5$1'
*1'',67=3.3%
*1'',67=3.3$
*1'',67=3.3&
*1'',67=6831,1
23(132/(23
7SNS
'HOD\
6(77,1*
7SNS
7SNS
)/(;/2*,&23(5$1'6
)/(;/2*,&23(5$1'
)/(;/2*,&23(5$1'
*1'',67=23$
*1'',67=23%
)/(;/2*,&23(5$1'6
*1'',67=23&
*1'',67=23
)/(;/2*,&23(5$1'
$1'
$1'
25
25
25