Description of Operation
GARD 8000 Distance Relay
RFL Electronics Inc.
The overvoltage elements pick up as soon as the measured voltage is above the set threshold, and a trip
signal is issued if the voltage maintains a value above for the duration of the timer. As soon as the
voltage drops below the set value plus the settable reset ratio (50 - 99%) the element and timer reset.
Figure 9-60. Block Diagram for Phase Overvoltage units
9.17.3
GROUND OVERVOLTAGE UNITS (59)
There are two ground overvoltage units, 59G-1 and 59G-2. Each unit has a pick-up setting and a timer
setting.
The ground voltage is computed from the phase voltages as:
3V
0
= V
A
+ V
B
+ V
C
The overvoltage elements pick up as soon as the measured voltage is above the set threshold, and a trip
signal is issued if the voltage maintains a value above for the duration of the timer. As soon as the
voltage drops below the set value plus the settable reset ratio (50 - 99%) the element and timer reset.
August 1, 2009
9-67
973.334.3100
