Functions
2.13 Flexible Protection Functions
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A4, Release date 08.2010
206
In Chapter 2.14 an application example for the function „Reverse Power Protection“ is illustrated.
The protection functions (a maximum of 20) operate independently. The following description of one function
also applies to all additional flexible functions. The logic diagram in Figure 2-77 illustrated the description.
Function Logic
The function can be switched ON and OFF or, it can be set to Alarm Only. In this status, a pickup condition
will neither initiate fault recording nor start the trip time delay. Tripping is thus not possible.
Changing the Power System Data 1 after flexible functions have been configured may cause these functions
to be set incorrectly. Message (FNo.235.2128 „$00 inval.set“) reports this condition. The function is in-
active in this case and function's setting has to be modified.
Blocking Functions
The function can be blocked via binary input (FNo. 235.2110 „>BLOCK $00“) or via local operating terminal
(„Control“ -> „Tagging“ -> „Set“). Blocking will reset the function's entire measurement logic as well as all
running times and indications. Blocking via the local operating terminal may be useful if the function is in a
status of permanent pickup which does not allow the function to be reset. In context with voltage-based char-
acteristics, the function can be blocked if one of the measuring voltages fails. Recognition of this status is either
accomplished by the relay's internal „Fuse-Failure-Monitor“ (FNo. 170 „VT FuseFail“; see section 2.10.1)
or via auxiliary contacts of the voltage transformer CB (FNo. 6509 „>FAIL:FEEDER VT“ and FNo. 6510
„>FAIL: BUS VT“). This blocking mechanism can be enabled or disabled in the according parameters. The
associated parameter BLK.by Vol.Loss is only available if the characteristic is based on a voltage measure-
ment.
When using the flexible function for power protection or power monitoring, it will be blocked if currents fall below
0.03 I
Nom
.
Power P Real power Reverse power protection
Power protection
32R, 32,
37
XX
Q Reactive power Power protection 32 X X
cos ϕ Power factor Power factor 55 X X
Binary input – Binary input Direct coupling without phase refer-
ence
Characteristic
Group
Characteristic / Measured Quantity Protective Function ANSI No. Mode of Operation
Three-
phase
Single-
phase
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