Power system voltage control by distributed expert systems

Under‐impedance load shedding: a new preventive action against voltage instability

“…10, where the impedance curve is down-sampled to 100 sample/s in order to clarify its time sample values. Using (15), the calculated time delay for the UILS relay of bus 2 is 0.5 s. It means that if 50 consecutive samples of impedance trajectory are located inside the load shedding zone, the relay should issue the trip To evaluate the effect of the proposed load shedding scheme, the trip command of UILS relay is activated to disconnect the motor load. Fig.…”

“…The conventional remedial action against voltage instability is under-voltage load shedding (UVLS) [14][15][16]. For a predefined time, if the voltage remains below a specified level, some predetermined loads are curtailed.…”

Wavelet-Based Power System Stabilizer

“…Power system stability can be classified as: voltage stability, frequency stability, and rotor angle stability [1] [3]. The voltage stability is the ability of a power system to maintain the acceptable voltage at all buses in the system under normal operating conditions and after being subjected to a disturbance [4] [5]. The frequency stability is the ability of a power system to maintain the frequency stable after a disturbance [4] [6].…”