Transients - Siemens SICAM Q100 Device Manual

4.1.3

Transients

SICAM Q100 detects temporary overvoltages as transients if the instantaneous value of the primary rated volt-
age exceeds the parameterized reference value at one or several sampling points. Detect and capture tran-
sients as short as 100 µs at 50 Hz (80 µs at 60 Hz).
The following data and values are determined during the evaluation of the transients in SICAM Q100 and listed
in the window Transient detection (see Chapter 8.4.2.7):
• Serial number of the event
• Time when transients start to occur (time stamp with date and time)
• Affected phase (a, b, c, ab, bc, ca)
• Transient duration
Parameterized reference value (in %) is up to 240 % of the primary rated voltage.
Voltage
Voltage
0
A transient will be detected if the instantanious value of the voltage (measured as sample) is higher than a given voltage reference level.
Once the detected sample is higher than the voltage reference level the end of the transient is detected when the sample value is lower
than the reference value minus 8 % of the reference value.
We can detect transients with a minimum length of 1/Fs which is 1/10 240 Hz = 97.6 s.
We can detect 10 (used in order to limit memory needs as well as later log entries, the number can be changed in firmware) consecutive
transients in one 10/12 cycle window.
Figure 4-1
SICAM Q100, 7KG95xx, Device Manual
E50417-H1040-C522-A4, Edition 03.2018
Measured
Sample time
resolution
Transient Detection
4.1 Power Quality Measuring System and Recording System
Highest voltage which can be measured with internal ADC
Transient reference level
Transient Off Detection Level = - 8 % Transient reference level
Detected transient duration
Real transient duration
sample
Detected
time stamp
4 Measured Quantities and Recording
Time
Time
31