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Figure from:Quick Fault Detection on Transmission line using Wavelet Transforms (Simulink model).

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These relays are used especially for the ac circuits. In this a movable disc is arranged between the magnets. There are three types of induction relays.

Figure 6 These relays are used especially for the ac circuits. In this a movable disc is arranged between the magnets. There are three types of induction relays.

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In this (fig.4) type of circuit breaker the direction of air flow is perpendicular to the direction of arc flow.
In this (fig.4) type of circuit breaker the direction of air flow is perpendicular to the direction of arc flow.
The transmitter generates high frequency output voltage when a positive voltage (positive half of sinusoidal voltage is applied to the control circuit of the transmitter. The high frequency output is applied between one phase and the ground. Each receiver receives high frequency currents from its local transmitter as well a, currents from the transmitter at the other end and converting it into a dc. voltage, which is applied to the comparer circuit. The output of the converting network is also applied to the comparer circuit. The comparator controls the operation of the tripping relay, which in turn controls the operation of the circuit breakers at each end of the line. The blocking network forms a resonant network, which offer: negligible impedance to power-frequency currents, but offers very high impedance to carrier currents. carrier- current blocking network, comparer and a tripping relay.
The transmitter generates high frequency output voltage when a positive voltage (positive half of sinusoidal voltage is applied to the control circuit of the transmitter. The high frequency output is applied between one phase and the ground. Each receiver receives high frequency currents from its local transmitter as well a, currents from the transmitter at the other end and converting it into a dc. voltage, which is applied to the comparer circuit. The output of the converting network is also applied to the comparer circuit. The comparator controls the operation of the tripping relay, which in turn controls the operation of the circuit breakers at each end of the line. The blocking network forms a resonant network, which offer: negligible impedance to power-frequency currents, but offers very high impedance to carrier currents. carrier- current blocking network, comparer and a tripping relay.
MRA is designed to give good time resolution and poor frequency resolution at high frequencies and good frequency resolution and poor time resolution at low frequencies. This approach makes sense especially when the signal at hand has high frequency components for short durations and low frequency components for long durations. Fortunately, the signals that are encountered in practical applications are often of this type. For example, the following shows a signal of this type. It has a relatively low frequency component throughout the entire signal and relatively high frequency components for a short duration somewhere around the middle.
MRA is designed to give good time resolution and poor frequency resolution at high frequencies and good frequency resolution and poor time resolution at low frequencies. This approach makes sense especially when the signal at hand has high frequency components for short durations and low frequency components for long durations. Fortunately, the signals that are encountered in practical applications are often of this type. For example, the following shows a signal of this type. It has a relatively low frequency component throughout the entire signal and relatively high frequency components for a short duration somewhere around the middle.
Meyer
Meyer
This family is obtained from the biorthogonal wavelet pairs. This family is built starting from the Gaussian function by taking the pth derivative of f
This family is obtained from the biorthogonal wavelet pairs. This family is built starting from the Gaussian function by taking the pth derivative of f
Integer p is the parameter of this family. FIR based approximation of the Meyer wavelet
Integer p is the parameter of this family. FIR based approximation of the Meyer wavelet
Fc- wavelet centre frequency A complex frequency B-spline wavelet is defined by
Fc- wavelet centre frequency A complex frequency B-spline wavelet is defined by
In the above graph the second graph represents the three-phase AC current when the AG fault is occurred i.e. phase A to ground fault at the receiving end side.
In the above graph the second graph represents the three-phase AC current when the AG fault is occurred i.e. phase A to ground fault at the receiving end side.
two phase currents also and the total three phase current comes to the normal condition when the transition time is completed.
two phase currents also and the total three phase current comes to the normal condition when the transition time is completed.
The above waveforms represents the wavelet transform of the phase A current at the receiving end side by using db1.1 mother wavelet and by using this the standard deviations of the detail coefficients are obtained.
The above waveforms represents the wavelet transform of the phase A current at the receiving end side by using db1.1 mother wavelet and by using this the standard deviations of the detail coefficients are obtained.
The above figure represents the single phase AC current of phase A.
The above figure represents the single phase AC current of phase A.
So the above graph represents the single phase AC current of phase A when the AG fault is applied. So by applying the W avelet transform to this signal then the standard deviations of the detail coefficients are obtained.
So the above graph represents the single phase AC current of phase A when the AG fault is applied. So by applying the W avelet transform to this signal then the standard deviations of the detail coefficients are obtained.
So the above figure represents the Wavelet Transform of the single phase AC current of phase A at the sending end side.
So the above figure represents the Wavelet Transform of the single phase AC current of phase A at the sending end side.