GE Multilin 565, Instruction Manual

Page: 178 / 198

RELAY TESTING
8-4
before. This verifies the accuracy of the curve in use.
When the tests are complete, reprogram the ground instan-
taneous trip delay, overcurrent pickup, and curve number
setpoints to their original values.
Voltage Input Function Check
Enter the setpoints mode and read the VT nominal second-
ary voltage from message S 9.3. Adjust the single phase
variac in the test setup until the phase voltage meter reads
the nominal voltage. Put the 565/575 Relay in Actual values
mode, and read the phase voltage from messages A 6.2 to
6.4 or A 6.5 to 6.7, depending on the sensing system. Verify
that these correspond to the feeder primary volts entered in
S 9.4.
Undervoltage Trip and Alarm Check
View message S 9.5 to determine if the undervoltage trip is
enabled. If not, select and store ENABLED in this message.
Read the undervoltage trip level from message S 9.6 and set
this at a convenient value, say 90%. Set the undervoltage
time delay to 1 second in message S 9.7. Check the relay to
which the undervoltage trip has been assigned in message S
9.8. For the purposes of this test, the trip and Aux 1 relays are
used.
Slowly lower the phase voltage injected by the test set variac
to 90% of the nominal level and verify that the assigned
relays are activated. For example, if the nominal secondary
voltage is 240 Volts, and the trip level was selected as 90%,
the selected relays should be activated when the voltage is
dropped below 90% of 240 or 216 Volts. Note that the breaker
must be closed.
The undervoltage alarm function operation can now be
checked by following a similar procedure, with reference to
messages S 9.9 to 9.12 instead of S 9.5 to 9.8.
Overvoltage Trip and Alarm Check
View message S 9.13 to determine if the overvoltage trip is
enabled. If not, select and store ENABLED in this message.
Read the overvoltage trip level from message S 9.14 and set
this at a convenient value, say 115%. Set the overvoltage
time delay to 1 second in message S 9.15. Check the relay to
which the overvoltage trip has been assigned in message S
9.16, for the purposes of this test, the trip relay is used.
Slowly increase the phase voltage injected by the test set
variac to 115% of the nominal level and verify that the trip or
other assigned relay is activated. For example, if the nominal
voltage is 240 Volts, and the trip level was selected as 115%,
the selected trip relay should be activated when the voltage
is increased above 115% of 240 or 276 Volts. Note that the
breaker must be closed.
The overvoltage alarm function operation can now be checked
by following a similar procedure with reference to messages
S 9.17 to 9.20 instead of S 9.13 to 9.16.
Output Relay Functional Check
The operation of the output relays can be checked by enter-
ing the setpoints mode page 8 and energizing each in turn
using messages S 8.2 to S 8.4. Energizing each relay should
cause the corresponding light on the test setup to illuminate,
when the relay normally open contacts close. Note that the
Aux 3 relay is failsafe and that its corresponding LED will go
out. The corresponding front panel LED will also indicate the
status of the relay. The normally closed contacts of each
relay may also be checked, by first disconnecting the AC
voltage which is present at the contacts. Now connect an
ohmmeter across the contact and energize the correspond-
ing relay, as above. For example, terminals 59 and 46 are
used for Auxiliary relay 1 normally closed contact. Verify that
the contact is first closed (conducting) and then indicates an
open state when the relay is energized. Once again, note
that Aux 3 is failsafe and that its normally open contacts can
be tested in a similar manner. At first the contacts should be
open and then after energizing they should be closed (con-
ducting).
Analog Input Function Check
The analog input may be checked by injecting known analog
signals and verifying that the correct values are displayed.
First check that the analog input feature is enabled, in
message S 5.2 of setpoints. If not, select enabled, using the
NEXT CHOICE key. Read and make a note of the minimum
and maximum scale factors in use from messages S 5.7 and
5.8. Set the injected current on the milliamp current source
adjustment to 4 milliamps. Read the value of the analog input
from message A 2.3. This should be the same as the
minimum scale factor read in setpoints. Adjust the injected
current on the milliamp current source to 20 milliamps. Read
the value of the analog input from message A 2.3 of actual
values. This should be the same as the maximum scale
factor read in page 5 of setpoints.
Analog Output Function Check
The analog output feature can be checked as follows. First
set the analog out parameter in page 6 of Setpoints to
external analog select. Next select an output parameter by
setting the correct combination of analog select switches.
For example, to select phase A current as the output param-
eter, switches A to D are open. Adjust the test set phase
current adjustment to inject a convenient level of phase
current. For example, 0.5 Amps might be injected for a relay
with a 1 Amp CT secondary or 2.5 Amps for a 5 Amp CT
secondary. Read the value of the analog output at terminals