Siemens SIPROTEC 7SD610 Manual page 44

Functions
2.1 General
Example:
Transformer Yy6d5
For the Y end set: VECTOR GROUP I = 0,
For the y end set: VECTOR GROUP I = 6,
For the d end set: VECTOR GROUP I = 5.
If a different winding is selected as reference winding, e.g. the d winding, this has to be considered accordingly:
For the Y end set: VECTOR GROUP I = 7 (12 - 5),
For the y end set: VECTOR GROUP I = 6,
For the d end set: VECTOR GROUP I = 0 (5 - 5 = 0 = reference side).
Address 1161 VECTOR GROUP U is normally set to the same value as address 1162 VECTOR GROUP I.
If the vector group of the transformer is adapted with external means, e.g. because there are matching trans-
formers in the measuring circuit that are still used, set VECTOR GROUP I = 0 at all ends. In this case the dif-
ferential protection operates without proper matching computation. However, the measuring voltages beyond
the transformer would then not be adapted in the device and therefore not be calculated and displayed correct-
ly. Address 1161 VECTOR GROUP U eliminates this deficit. Set the correct vector group of the transformer ac-
cording to the above-mentioned considerations.
Address 1162 VECTOR GROUP I is therefore relevant for the differential protection whereas address 1161
VECTOR GROUP U serves as a basis for the calculation of the measured voltages beyond the transformer.
At address 1163 TRANS STP IS you can enter whether the power transformer starpoint facing the device is
earthed or not. If the starpoint is earthed, the device will eliminate the zero sequence current of the relevant
side, since this zero sequence current can otherwise cause a spurious tripping in case of a ground fault outside
of the protected zone.
Circuit Breaker Status
Information regarding the circuit breaker position is required by various protection and supplementary functions
to ensure their optimal functionality. The device has a circuit breaker status recognition which processes the
status of the circuit breaker auxiliary contacts and contains also a detection based on the measured currents
and voltages for opening and closing (see also Section 2.16.1).
In address 1130 the residual current PoleOpenCurrent is set, which will definitely not be exceeded when
the circuit breaker pole is open. If parasitic currents (e.g. through induction) can be excluded when the circuit
breaker is open, this setting may be very sensitive. Otherwise this setting must be increased. Usually the pre-
setting is sufficient. This parameter can only be altered in DIGSI at Display Additional Settings.
The switch-on-to-fault activation (seal-in) time SI Time all Cl. (address 1132) determines the activation
period of the protection functions enabled during each energization of the line (e.g. fast tripping high-current
stage). This time is started by the internal circuit breaker switching detection when it recognizes energization
of the line or by the circuit breaker auxiliary contacts, if these are connected to the device via binary input to
provide information that the circuit breaker has closed. The time should therefore be set longer than the circuit
breaker operating time during closing plus the operating time of this protection function plus the circuit breaker
operating time during opening. This parameter can only be altered in DIGSI at Display Additional Settings.
Address 1134 Line Closure specifies the criteria used by the integrated circuit breaker switching detection.
Only with ManCl means that only the manual close signal via binary input or the integrated control is eval-
uated as closure. I OR U or ManCl means that additionally the measured currents or voltages are used to
determine closure of the circuit breaker, whereas CB OR I or M/C implies that either the currents or the states
of the circuit breaker auxiliary contacts are used to determine closure of the circuit breaker. If the voltage trans-
formers are not arranged on the line side, the setting CB OR I or M/C must be used. In the case of I or
Man.Close only the currents or the manual close signals are used to recognise closing of the circuit breaker.
44
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011