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• The above described tests of the measured quantities also have to be performed at the other end of the
tested current path. The current and voltage values as well as the phase angles of the other end can also
be read out locally as percentage values. Please observe that currents flowing through the object (without
charging currents) ideally have opposite signs at both ends, i.e. they are turned by 180°. In the „WEB-Mon-
itor", the local and remote measured values can be shown graphically. An example is shown in Figure 3-30.
• The protected object is now switched off, i.e. the circuit breakers are opened.
Polarity check for voltage input U
Depending on the application of the voltage measuring input U
suring voltage is connected to this input, this section is irrelevant.
is used for measuring a voltage for overvoltage protection (P.System Data 1 address 210 U4
If input U
4
transformer = Ux transformer), no polarity check is necessary because the polarity is irrelevant here.
The voltage magnitude was checked before.
If input U
is used for the measurement of the displacement voltage U
4
transformer = Udelta transf.), the polarity is checked together with the current test (see below).
is used for measuring a busbar voltage for synchronism check (P.System Data 1 address 210
If input U
4
U4 transformer = Usy2 transf.), the polarity must be checked as follows using the synchronism check
function:
Only for Synchronism Check
The device must be equipped with the synchronism and voltage check function which must be configured under
address 135 Enabled (see section 2.1.1.3).
The synchronisation voltage U
2.1.2.1).
If there is no transformer between the two measuring points, address 214 ϕ Usy2-Usy1 must be set to 0°
(see Section 2.1.2.1).
If the measurement is made across a transformer, this angle setting must correspond to the phase rotation re-
sulting from the vector group of the transformer (see also the example in section 2.1.2.1).
If necessary, different transformation ratios of the transformers may have to be considered from both measuring
points U
and U
sy1
The synchronism and voltage check must be switched ON under address 3501 FCT Synchronism.
An additional help for the connection check are the messages 2947 „Sync. Udiff>" and 2949 „Sync. ϕ-
diff>" in the spontaneous annunciations.
• Circuit breaker is open. The feeder is isolated (zero voltage). The VTmcb's of both voltage transformer cir-
cuits must be closed.
• For the synchronism check the program AR OVERRIDE = YES (address 3519) is set; the other programs
(addresses 3515 through 3518) are set to NO.
• Via binary input (No. 2906 „>Sync. Start AR") initiate the measuring request. The synchronism check
must release closing (message „Sync. release", No. 2951). If not, check all relevant parameters again
(synchrocheck configured and enabled correctly, see Sections 2.1.1.3, 2.1.2.1 and 2.18.2).
• Address 3519 AR OVERRIDE must be set to NO.
• Then the circuit breaker is closed while the line isolator is open (see Figure 3-32). Both voltage transformers
therefore measure the same voltage.
• The program AR SYNC-CHECK = (address 3515) is set for synchronism check.
• Via binary input (No. 2906 „>Sync. Start AR") initiate the measuring request. The synchronism check
must release closing (message „Sync. release", No. 2951).
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
4
must be entered correctly at address 212 Usy2 connection (see Section
sy2
at address 215 Usy1/Usy2 ratio.
sy2
Mounting and Commissioning
, a polarity check may be necessary. If no mea-
4
(P.System Data 1 address 210 U4
en
3.3 Commissioning
551
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