Siemens SIPROTEC 7UT613 series Manual page 394

3 Mounting and Commissioning
Power Functions
394
• Tests for positive and negative sequence system voltages are easiest with three-
phase symmetrical testing. The positive sequence system can be obtained by sym-
metrical test voltages, the negative sequence system by exchanging two phases.
The setting value U
1
against starpoint. For single-phase testing the positive and negative sequence
1
voltage are / of the test voltage.
3
• Testing the zero system can be done single-phase at any of the three-phase voltage
inputs. Zero sequence voltage is set to 3 · I
must-pickup value.
• If a flexible function is configured for frequency monitoring, the pickup value can
only be tested with a voltage source with variable frequency. A special test is not
needed, as the device always determines the frequency from the positive sequence
system of the three phase voltages. A possibly wrong allocation of the measuring
quantities for the frequency determination is therefore excluded.
For flexible functions with power functions test voltages and currents are needed. Volt-
ages are applied to the three voltage measuring inputs and the currents fed into those
current measuring inputs, that the voltages are assigned according to Section 2.1.4
under "Assignment of Voltage Measuring Inputs".
Important for the load direction and signs:
• the polarity of the test quantities,
• setting of the polarity for the current measuring location/side in the test, according
to polarity setting (e.g. Address 511 STRPNT->OBJ M1 for measuring location 1),
• setting for the sign of power under Address 1107 P,Q sign in system data 2.
For default settings the active power for the three-phase testing with in-phase currents
and voltages amounts to √3 · U
with in-phase test quantities
from the positive-sequence systems, which amount to
as in the voltages.
Reactive power can only be tested single-phase if a phase displacement between
current and voltage is possible. With three-phase test quantities, reactive power can
be simulated by phase exchange, although a phase displacement between currents
and voltages is not possible. The following table gives examples. Here, the factors for
active and reactive power refer to the power S = √3 · U
phase segregated connection, the voltages have been swapped cyclically. An anti-
cyclic exchange (e.g. L2 ↔ L3) is not permissible as the positive-sequence system
would amount to zero in that case.
and U correspond to the magnitude of every test voltage
2
0
· I
(U phase-phase). For single-phase testing
test test test
1
/ of the three-phase value as the power is calculated
9
, the test voltage corresponds to the
1
/ each in the currents as well
3
· I
. The currents are in
test test
7UT613/63x Manual
C53000-G1176-C160-2