GE RPV311, Техническое руководство

Страница: 137 / 295

RPV311 Chapter 6
– Records
RPV311-TM-EN-7 137
3.2 Sampling Rate and Acquisition
The acquisition module RA333 has 3 independent channels (one circuit A, B, C), with
an 8 bit A/D converter. The sampling frequency acquisition is 5 MHz, synchronized by
a PPS signal, which means one acquisition each 200 ns.
The acquisition module conditions the line voltage signal. With an efficient band-pass
filter the passing frequency is limited between 1 kHz and 1 MHz.
The module constantly acquires signals and storing the measured values locally in a
64 Mbytes RAM (approximately 4 seconds). The data is written into a circular buffer
where the oldest data will be overwritten by the latest until a threshold violation
occurs.
On detecting violation of the threshold, the memory writing is interrupted. The
memorized data is sent to the processing module at this moment. The complete
transfer of data takes about 2 minutes, and in this time the B
USY
indicators are lit.
While data is being transferred to the processing module (2 minutes), new TW
records will not be registered;. During this time, the other acquisition and processing
modules continue functioning normally.
3.3 Recording Times
The recording parameters are fixed and the record has 100 ms before the violation of
the limit and one cycle after, approximately 117 ms at 60Hz and 120 ms at 50 Hz. The
duration of recording may vary slightly but this does not cause in implications for
fault location.
4
Steady-State Records
Steady-state records can be created by the following means:

Average Series;

Harmonics;

Flicker.
4.1 Average Series
The equipment continuously records averaged values of
Values of average series recorder
RMS (voltage) Simple average
RMS (current) Simple average
Voltage imbalance Simple average
Frequency Simple average
Voltage total harmonic
distortion Quadratic average