3.5
Internal Software Test Profiles
The test profiles are performed on the Relay Under Test to verify the relay is operating correctly.
The following describes the procedures to test a unit:
3.5.1 Pulse Ramping
The Pulse Ramping may be used to determine reach values for multi-zone relays, without
defeating the zone timer elements. The Pulse Time is set so that the test current is only on long
enough for the selected zone to operate. The following figure shows the current pulse generated
by the test unit.
Figure 25 Pulse Ramp
Select the fault type from the several available fault types: phase-to-ground; phase-to-phase; two
phases-to-ground; and three phase. Hold the voltage or the current constant. There are different
available pre-fault voltages to choose from. The user may enter a different value if desired. The
pre-fault current range is from 0 to 9.99 amps. The test starts with a pre-fault current (voltage) for
the Pre-fault Time Off delay to ensure the relay energizes (polarize) before starting the test. The
Pulse Time Off Delay Time is specified in milliseconds with the factory default value set at 1000
mSec (60 cycles at 60 Hz). The pulse ramping can begin once the relay is energized. The first
pulse has a selectable amplitude for the start value. This value is held for the defined Pulse Time
(in cycles). The generator output returns to the Pre-fault Value. The time the relay remains at this
level is determined by the Delay Time minus the Pulse Time. The next pulse is increased by the
increment value specified. The voltage magnitude and angle will be calculated for each of the
three phases when the test is complete. The current is calculated for the three phases. The
percent error is calculated for the Reach. The resistance is calculated for the final value. A fault
calculator, based on symmetrical components, is used to perform the fault calculations.
3.5.2 Ramping
The Ramping test maybe used to determine pickup values, verify single-zone impedance relays
or the outer most zone of a multi-zone impedance relays. For example, using the Ramping for
finding the reach of an impedance relay, select the fault type from a list. Determine whether the
voltage or the current is to be held constant. In the angle of torque calculation both the voltage
and current are held constant while the angle is ramping. Start with a pre-fault current (voltage)
for the Pre-fault Delay Time to ensure the relay is energized before the test begins. The Pre-fault
Delay Time has been specified in milliseconds and the factory default value is 1000 milliseconds
(60 cycles at 60 Hz). The ramping starts once the relay energizes. The generator output is set to
the start value specified. The generator holds the value for the specified Delay Time by the fault
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