Siemens SIPROTEC 4 7UT6 Series, Руководство пользователя

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as the internal connections have to be checked. Verification of the system connections is contained in a later
primary commissioning (Section
3.3 Commissioning under “Circuit Breaker Failure Protection Tests”).
In these secondary testings mainly the correct assignments of flexible function to the analogue measured
inputs are verified, as well as to the binary in/outputs.
Every flexible function is individually checked, as each was individually configured.
Current Functions
For flexible functions with Current Input test currents are fed into the current input, i.e. one after the other,
those that are relevant to the tested flexible functions. For functions working on exceeding currents a slowly
increased test current is applied until the function trips. Value undershooting above a pickup value it is
decreased. Keep in mind that the corresponding message can be delayed if a time delay is set.
!
CAUTION
Tests with currents that exceed more than 4 times the rated device current cause an overload of the input
circuits and may only be performed for a short time.
See Technical Data
²
Afterwards the device has to cool off!
When checking pickup values keep in mind:
•
If the current function is assigned to one side of the main protective object, the pickup values are referred
to the rated current (
Ι / Ι
N S
). Magnitude factors are included. The rated current of the side can be deter-
mined analogue to the equations above under: “Differential Protection”. The test current has to be
converted to secondary value.
•
If the current function is assigned to a measured location and the pickup values are set secondary, the
pickup value equals the secondary setting value.
•
If the current function is assigned to a measured location and the pickup values are set primary, the
setting value is to be converted to secondary value, so that the pickup value at the secondary test current
is maintained. For the conversion the transformation of the current transformer (set for this device meas-
uring input) is important.
•
Tests for positive and negative sequence system currents are easiest with three-phase symmetrical
testing. The positive sequence system can be obtained by symmetrical test currents, the negative
sequence system by exchanging two phases. The setting values
Ι
1 and
Ι
2 correspond to the magnitude
of each test current. For single-phase testing the positive and negative sequence currents are 1 /
3
of the
test current.
•
Testing the zero system can be done single-phase at any of the three-phase current inputs. Zero
sequence current is set to 3 ·
Ι
0
, the test current corresponds to the must-pickup value.
Voltage Functions
For flexible functions with Voltage Detection the test voltages are fed to into the single-phase or to the
voltage measuring inputs. This is also valid for the frequency function. A symmetrical three-phase voltage
source is recommended. If testing takes place with a single-phase current source, special considerations are
applicable, which will still be given. For functions working on exceeding voltages slowly increased test voltage
is applied until the function trips. Value undershooting above a pickup value it is decreased. Keep in mind that
the corresponding message can be delayed if a time delay is set.
Mounting and Commissioning
3.3 Commissioning
368 SIPROTEC 4, 7UT6x, Manual
C53000-G1176-C230-5, Edition 09.2016