S. A. Saleh

A New Implementation Method of Wavelet Packet Transform Differential Protection for Power Transformers

This paper presents an innovative implementation of the wavelet packet transform using Butterworth passive filters for differential protection of power transformers. The proposed implementation is based on designing cascaded stages of high pass 3

Real-time testing of a WPT-based protection algorithm for three-phase power transformers

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Testing of a Wavelet-Packet-Transform-Based Differential Protection for Resistance-Grounded Three-Phase Transformers

order Butterworth filters with cut-off frequencies identical to the cut-off frequencies of wavelet packet transform associated digital quadrature mirror filters. These high pass filters are designed to extract the second level high frequency components present in the three-phase differential currents. The extraction of these frequency components is required in order to detect and classify transients in three-phase power transformers. The output of the designed Butterworth high pass filters is utilized to initiate a trip signal in case of internal fault currents. The 3

Development and Testing of a New Controlled Wavelet-Modulated Inverter for IPM Motor Drives

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Implementing and testing d − q WPT-based digital protection for micro-grid systems

order Butterworth high pass filters are designed to simplify their practical implementation as well as their integration with the differential protective relay for the tested power transformer. Different magnetizing inrush, through-fault and internal fault currents are investigated for different loading conditions. Performances of the proposed Butterworth passive filter-based differential relay are compared with those of the digital wavelet packet transform-based relay. Comparison results show that the Butterworth filter wavelet packet transform-based differential relay is able to provide a low cost good diagnosis and fast responses to internal fault currents.

Development and Experimental Validation of Resolution-Level Controlled Wavelet-Modulated Inverters for Three-Phase Induction Motor Drives

This paper presents real-time implementation and testing of a wavelet-packet-transform-based algorithm for power transformer protection. The proposed algorithm is implemented using a DS1102 digital signal processor board and tested on two different three-phase power transformers. Different magnetizing inrush, normal (through-fault) and internal fault currents are investigated for different loading conditions. The results show a complete independence from both the transformer parameters and current transformer saturation. In addition, the proposed algorithm has reduced computational burden, high speed, high accuracy, small required memory, and high reliability. In all cases of the investigated internal faults, the proposed algorithm is capable of identifying the fault and generating a trip signal in less than a quarter cycle based on a 60-Hz system.

Development and Experimental Testing of a 3o Resolution-Level Controlled WM Inverter-Fed Induction Motor

This paper presents an extension of real-time tests of a wavelet-packet-transform-based technique for the differential protection of three-phase power transformers. The proposed technique is implemented using a DS1102 digital signal processor board and tested on two different three-phase power transformers with neutral resistance grounded. Different magnetizing inrush and internal fault currents are investigated with current transformer (CT) saturation for different loading conditions, including capacitive loads. The results show a complete independence from transformer parameters, load types, grounding method, or CT saturation. Furthermore, the proposed technique has high speed, good accuracy, small required memory, and reliable responses with reduced computational burden. In all cases of the investigated internal faults, the proposed algorithm is capable of identifying the fault and generating a trip signal in less than a quarter cycle based on a 60-Hz system.

On performances of wavelet modulated three phase AC-DC converters

This paper presents the development, implementation, and performance testing of a novel resolution-level vector controller (RLVC) for a wavelet-modulated (WM) inverter-fed interior permanent-magnet (IPM) motor drive system. The RLVC is designed to adjust the output voltage of the WM inverter in response to changes in the load torque and command speed. The adjustments in the WM inverter output voltage is accomplished through changing the maximum value of the scale j that is required to generate the WM inverter switching signals. The complete IPM motor drive system incorporating the RLVC is successfully implemented in real time using a digital signal processor board ds1104 for a laboratory 1-hp IPM motor. The performances of the proposed RLVC IPM motor drive system are investigated at different dynamic operating conditions, including sudden changes in the command speed and load torque. The simulated and experimental performance results show stable, fast, and accurate adjustments of the inverter output voltage in response to load and speed changes in the tested IPM motor drive system.

Real-Time Implementation and Testing of a Wavelet-Controlled Dynamic Voltage Restorer

This paper introduces an implementation procedure and performance testings of a wavelet packet transform (WPT)-based digital protection for micro-grid systems. This digital protection is structured for detecting and classifying faults based on the values of the WPT coefficients of the high frequency sub-bands present in the d − q-axis current components. The WPT coefficients are determined using the Daubechies db4 wavelet basis functions, which are found optimal for analyzing transient disturbances likely to occur in power systems and electric machines. The proposed digital protection is implemented for experimental performance testing on a test micro-grid system that is constructed as a laboratory scale of an actual micro-grid system located in Fermeuse, Newfoundland, Canada. Several transient disturbances occurring in different parts of the test micro-grid system are experimentally investigated. Performance results demonstrate significant capabilities of the d − q WPT-based digital protection for accurate and reliable detection and classification of fault conditions, along with fast response to classified faults.

Testing of a wavelet packet transform-based differential protection for resistance-grounded three-phase transformers

This paper presents the development, implementation, and performances of a resolution-level vector controller (RLVC) for three-phase induction motor (IM) drive systems. The RLVC is structured to adjust the output voltages of a three-phase voltage-source wavelet-modulated inverter which is used to supply a three-phase IM. The objectives of the RLVC are established by controlling the quadrature axis component of the stator currents while maintaining a constant direct axis component of the stator currents. The complete IM drive system incorporating the RLVC is successfully implemented in real time for performance testing using a three-phase squirrel-cage IM. The performances of the proposed IM drive system are tested for sudden changes in load torque and command speed. Simulated and experimental performances demonstrate reliable, stable, fast, and accurate responses of the proposed controller under various operating conditions.