Arbiter Systems 1133A, Руководство по эксплуатации

Страница: 141 / 192

11.28 Detecting Oscillatory Transients and Other Anomalies 121
11.28 Detecting Oscillatory Transients and Other Anomalies
Special logic is included in the 1133A to implement the algorithms described by Schulz and Laios
[1], which are designed to detect power system anomalies such as oscillatory transients. There
are six channels dedicated to performing this function in the 1133A (Table 6-4). Each of these
may have any of the 124 signals described above as its input. Each channel has three outputs:
a low-pass-filtered (bound) output, a rate-of-change output, and an oscillation-detector output.
Each channel also has three control parameters (in addition to the input signal selection): the
rate-of-change filter time constant (T1 in [1]); the oscillation-detector time constant (T2 in [1]);
and the oscillation-detector reset threshold, also described in [1]. These parameters control only
the operation of these signal-processing blocks, and do not in themselves generate any triggers. To
generate triggers, select one of the three outputs of one of the channels in this block. This serves as
an input to one of the 32 trigger channels. As recommended by Schulz and Laios, the input filtering
for this block is the BPA #1 low-pass, described in [2], which is a 12-point Hanning-weighted FIR
low-pass filter having a group delay of 0.3 seconds at a 20-per-second sampling rate.