Voltage-Jump Detection; Overview Of Functions; Structure Of The Function; Function Description - Siemens 7SJ82 Manual

Protection and Automation Functions

6.50 Voltage-Jump Detection

6.50 Voltage-Jump Detection

Overview of Functions

6.50.1
The Voltage-jump detection function has the following tasks:
•
Recognition of jumps in the phase or zero-sequence voltage (ΔV)
•
Generation of an indication when the measurands change by more than a configured threshold value
from one system cycle to the next.
The function for detecting jumps in the phase or zero-sequence voltage is an additional function used for indi-
cation purposes or for further processing in user-specific CFC logics. Pick up of the function therefore neither
opens a separate fault in the fault log nor generates an operate indication.

Structure of the Function

6.50.2
The Voltage-jump detection function is used in protection function groups based on voltage measurement. It
can be instantiated multiple times.
[dwstruku-011211-01.tif, 1, en_US]
Figure 6-332
6.50.3

Function Description

Voltage-jump detection operates directly with the sampled values without numeric filtering. This provides very
short response times to sudden changes in the voltage. The method used is not sensitive to slow changes of
amplitude or frequency.
By using a configurable selection of measured values, you can select from phase-to-ground voltages, phase-to-
phase voltages or the zero-sequence voltage. Voltage-jump detection is phase-selective.
The difference from the previous sampled value of 1 system cycle is calculated for each sampled value. The
rectified average is then determined for a ½ system cycle from this differential signal Δv(t). The rectified
average for sinusoidal measurands is then converted to a RMS value ΔV by subsequent multiplication by 1.11.
The resultant measurand ΔV is then compared with the threshold value.
If the parameter (_:101) Threshold is exceeded, the output indication
value is set to phase-to-phase, the sudden change in voltage is signaled selectively for the individual meas-
uring elements that have picked up (
phase or phase-to-ground voltages for measurement, the output indication data type used included the sepa-
rate phase information. If you have selected the zero-sequence voltage for measurement, the output indica-
tion data type used includes the N information. If the voltage-jump detection responds (ΔV
information is generated in the output indication in all cases.
Dropout occurs with a dynamically increased threshold value ΔU
Figure 6-333. Dynamic increase of the dropout threshold value achieves optimally short dropout times.
A timing element is added to the indication
pulse can be set using the parameter (_:102) Minimum pulse length. This gives the output indication
Pulse a reliable minimum size. If you activate the binary input >Pulse extension , you can prolong the
pulse duration even further. If the binary input
Pulse drops off when the configured time has elapsed and the falling edge of the binary input is detected. If
960
Structure/Embedding of the Function
Jump VAB , Jump VBC or Jump VCA ). If you have selected the phase-to-
in accordance with the information in
Limit
Jump . The element generates a pulse from this. The length of this
>Pulse extension has been activated, the indication
Jump is generated. If the measured
), the general
Limit
SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017