In this work, an approach was proposed to obtain the slow dynamics by projecting the trajectory of the postfault
system onto its slow manifold.
After the fault is detected, the output of the fault sensor is replaced immediately with the differential signal of the output from a normal displacement sensor to ensure the safety of the postfault
Once an electrical fault occurs in any distribution feeder, immediate fault classification plays an important role in postfault
analysis and power supply restoration.
For example, Support Vector Machine, Decision Tree, and Artificial Neural Network (ANN) are the widely used approaches to detecting instability of power systems by using postfault
trajectories within a few cycles .
Dai Pre, "Impact of Stator Winding of a Five-Phase Permanent-Magnet Motor on Postfault
Operations," IEEE Trans.
During the postfault
condition, the operating [delta] angle increases closer to 90[degrees], making the power system more prone to instability.
More important, this fixed scheme can usually balance the branch load in the postfault
network, which is an important index concerned by dispatchers.
For training pattern or input matrix formation, the postfault
samples (ten number) of fundamental components of three-phase voltages and currents of each circuit are extracted.
 Eduardo, C., Zanetta, L., 2004, "Fault Location in Transmission Lines Using One-Terminal Postfault
Voltage data," IEEE Trans.
To verify if an interval contains the faulty parameter value of the postfault
system, a parameter filter is built for this interval, which consists of two isolation observers corresponding to two interval bounds, and each isolation observer serves two neighboring intervals.
According to (6), when the DFIG is connected to the infinite grid, the postfault
rotor current is jointly determined by the generator parameters, active and reactive power outputs, terminal voltage dip, steady-state terminal voltage, and generator speed.
where [Y.sub.ii,f] and [Y.sub.ii,n] are the self-admittance of bus i of postfault
and prefault distribution network, respectively.