A number of studies have reported that grounding system performance is reduced due to the increase of the grounding impedance with increasing of the frequency of fault currents.
An increase in tectonic activity at the start of the Paleozoic resulted in an increase in the frequency of faulting and the formation, in the Tagil-Magnitogorsk depression, of a volcanic belt.
The estimation accuracy of fault area depends on the fault detection algorithm, the phase synchronization of the Global Positioning System (GPS) and the sampling frequency of Digital Fault Recorders (DFR) [22, 29]. Figure 4 illustrates a simple 2-bus transmission system to estimate the fault area using traveling wave.
where ϕ≡Φ/Φ0 is the strength normalized by the initial strength and α ≡ ω / ω c 0 = f / f c 0 is the observation frequency normalized by the characteristic frequency of the fault at the initial state.
By using Parseval's theorem and S-procedure, a new finite frequency method of fault detection for switched T-S fuzzy systems is formulated.
By filtering one of the dq0 components through the wavelet transformation, and by isolating band frequencies of interest, faults can be detected using the finite difference between samples of the filtered signal.
For bearing fault diagnosis by envelope analysis, the frequency of the bearing fault and several of its harmonics are required to assess the severity of the fault, because the number of harmonics in the envelope is directly related to information on the geometrics of the fault.
The frequencies of the fault and the unknown input disturbance are assumed to be in a finite range.
The reasons for the differences in lamellar structures are discussed on the basis of the frequencies of stacking fault formation on (0 0 0 1) planes as precursors to γ-precipitates.
In the bounding damage zones, networks of fracture sets make up an inner zone of fairly high frequency (20 30 f/m) of fault-parallel, long fractures connected by shorter fractures.
