Siemens SIPROTEC 7RW80 Manual page 80

Functions
2.6 Flexible Protection Functions
Function Blocking
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. If voltages are based on variables,
the function can be blocked if a measured voltage fails. This will be consequently detected by the auxiliary con-
tacts of the voltage transformer circuit breaker (FNo. 6509 „>FAIL:FEEDER VT" and FNo. 6510 „>FAIL:
BUS VT"). This blocking mechanism can be switched on or off via a parameter. The respective parameter
BLK.by Vol.Loss is only available if the variable is based on a voltage measurement.
Operating Mode, Measured Quantity, Measurement Method
The flexible function can be tailored to assume a specific protective function for a concrete application in pa-
rameters OPERRAT. MODE, MEAS. QUANTITY, MEAS. METHOD and PICKUP WITH. Via parameter
OPERRAT. MODE it can be determined whether the function operates 3-phase, 1-phase or no reference,
i.e. without (fixed) phase reference. The three-phase method evaluates all three phases in parallel. This implies
that threshold evaluation, pickup indications and trip time delay are accomplished selectively for each phase
and parallel to each other. When operating single-phase, the function employs a phase's measured quantity,
which must be stated explicitly. If the variable is based on the frequency or if the function direct coupling is used,
the operation method has no (fixed) phase reference. Additional parameters can be set to specify the used
MEAS. QUANTITY and the MEAS. METHOD. The MEAS. METHOD determines whether the function uses the
r.m.s. value of the fundamental component or the normal r.m.s. value (true RMS) that evaluates also harmon-
ics. Parameter PICKUP WITH moreover specifies whether the function picks up on exceeding the threshold
(>-element) or on falling below the threshold (<-element).
Characteristic Curve
The function's characteristic curve is always „definite time"; this means that the delay time is not affected by the
measured quantity.
80
SIPROTEC, 7RW80, Manual
C53000-G1140-C233-1, Release date 10.2010