Testing - ABB SPAF 140 C User Manual And Technical Description

Testing

Testing of the
combined frequency
and rate of change of
frequency relay
module SPCF 1D15
General
Start value
Trip time
The relay should be subjected to regular tests in
accordance with national regulations and in-
structions. The manufacturer recommends an
interval of five years between the tests.
The test should be carried out as a primary test,
which includes the entire protection arrange-
ment, from the instrument transformers to the
circuit breakers.
The test can also be carried out as a secondary
injection test. Then the relay has to be discon-
nected during the test procedure. However, it is
recommended to check the function of the sig-
nal and trip circuits as well.
Note!
Make sure that the secondary circuits of the
current transformers under no condition open
or are open, when the relay is disconnected and
during the test procedure.
The test is recommended to be carried out us-
ing the normal setting values of the relay and
the energizing inputs used. When required, the
test can be extended to include more setting
values.
The protection stages are tested with respect to:
- start value
- trip time
- trip indication, output relay operation
Test the start value by gradually dropping the
frequency, starting from the rated value, until
the relay starts. Record the frequency required
for starting. The value should be within the per-
mitted tolerances.
If the resetting value is to be tested as well, drop
the frequency, until the relay starts, and then in-
crease the frequency again, until the relay resets.
When multi-stage protection relays are tested,
the operation of the higher-set stages may cause
Apply a voltage of rated frequency to the relay.
Then drop the frequency of the voltage to a value
below the setting value. The frequency of the
supply voltage should be such that the differ-
ence between the trip level and the frequency
of the supply voltage is about twice the differ-
ence between the rated frequency and the trip
level. However, the absolute value of the rate of
change of frequency must not exceed 70 Hz/s,
because the relay perceives such a situation as a
As the settings of the relay modules affect the
operation of the relay (overfrequency/under-
frequency relay) and thus also the test proce-
dure, these instructions describe the general fea-
tures of the test procedure. The test procedure
presented here applies to the underfrequency re-
lay. A voltage supply unit allowing voltage and
frequency to be regulated is recommended to
be used. In addition, instruments for measur-
ing voltage, frequency and time are required.
During the test procedure the relay records fre-
quencies, rates of change of frequency, voltages
and relay operations. If the recorded data is used
for the collection of information for longer time
periods (for example, AR counters), these re-
gisters should be read before the test procedure
is started. After the test the registers are reset
and, if required, the readings of the AR counters
can be restored.
The relay settings may have to be changed dur-
ing testing. A PC program is recommended to
be used to read the relay settings before the test
is started.
problems to the testing of lower-set stages. Then
it is generally necessary to delay the operation
of the higher-set stages by changing the setting
values, or totally block the operation of the
higher stages by reconfiguring the SGR switches.
In such a case it is recommended to start the
test from the lowest stage and then proceed to
higher-set stages. The advantage of this method
is that the original settings of the stages really
are restored, because otherwise the test cannot
be carried out successfully.
disturbance and delays tripping by two cycles.
The operate time is the time from the moment
the frequency starts changing, until the relay
operates. The accuracy of the operate times
should be within the permitted tolerances.
The resetting time is the time measured from
the moment the current switch is opened, until
the relay resets.
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