| 摘要 |
<p>The subject of the invention is a method of subsynchronous resonance detection in electrical power systems with series capacitors. Voltage signals are measured on line and by using finding zero crossing points of discrete signal of measured voltage, positive and negative half cycles of the wave form of discrete signal of voltage are calculated in a computer device to which constant parameters are delivered by the user. The inventive method comprises the following actions:
€¢ creating a demodulated signal (U Dem ) of voltage by adding the minimum value of negative half cycle of the wave form of discrete processed signal (U x ) of voltage to the maximum value of positive half cycle of the wave form of discrete processed signal of voltage (U x ) for time intervals having a signal length (T L ), where (T L ) is a constant parameter, delivered by the user,
€¢ calculating a root mean square value (RMS) for demodulated signal of voltage U Dem and comparing it with the value of another constant parameter delivered by the user as the level of root mean square value (RMS Lev ) and when the value of (RMS) is smaller than the value of (RMS Lev ) it indicates that there is no subsynchronous resonance, and when the value of RMS is bigger than the value of (RMS Lev ), the presence of subsynchronous resonance is identified by the determination of voltage amplitude (A Fss ) of subsynchronous resonance and/or frequency (f Fss ) of subsynchronous resonance.</p> |
