[lo_GeneralFunctionality_20150323, 1, en_US]
Figure 6-188 Logic Diagram of the General Functionality
Measurand
The average value of negative-sequence voltage is determined by a settable time interval (parameter: Meas-
uring window). With the parameter Measuring window, you can adapt this function to all power-system
conditions.
You can set the parameter Measuring window with a large value to get a more accurate calculated result,
which leads to a longer pickup time however.
Blocking the Function with Measuring-Voltage Failure Detection
In case of blocking, the picked up function is reset. The following blocking options is available for the function:
•
From inside on pick up of the Measuring-voltage failure detection function (see section 9.3.2.1 Over-
view of Functions).
•
From an external source via the binary input signal
>Open
of the function block Volt.-transf. c. b., which
links in the tripping of the voltage-transformer circuit breaker.
The parameter Blk. by meas.-volt. failure can be set so that the measuring-voltage failure detection
blocks the function or does not block it.
Application and Setting Notes
Parameter: Measuring window
•
Default setting (_:2311:101) Measuring window = 1 cycle
With the parameter Measuring window, you can optimize the measuring accuracy or the pickup time
of this function.
For sensitive settings of the parameter Threshold, for example, lower than 10 % of the rated voltage,
Siemens recommends using a higher number of cycles. Siemens recommends 10 cycles, and in this
case, the pickup time is increased.
For further information, refer to chapter 12.32 Overvoltage Protection with Negative-Sequence Voltage .
Parameter: Blk. by meas.-volt. failure
•
Recommended setting value (_:2311:10) Blk. by meas.-volt. failure = yes
You use the Blk. by meas.-volt. failure parameter to control the behavior of the function when a
measuring-voltage failure is detected.
6.26.3.2
Protection and Automation Functions
6.26 Overvoltage Protection with Negative-Sequence Voltage
SIPROTEC 5, Overcurrent Protection, Manual 715
C53000-G5040-C017-8, Edition 07.2017
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