A correlation based method for discrimination between inrush and short circuit currents in differential protection of power transformer using Discrete Wavelet Transform: Theory, simulation and experimental validation

2013 ◽  
Vol 51 ◽  
pp. 168-177 ◽  
Author(s):  
M. Rasoulpoor ◽  
M. Banejad
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Experimental Validation ◽  
Power Transformer ◽  
Short Circuit ◽  
Discrete Wavelet ◽  
Differential Protection ◽  
Short Circuit Currents

A New Algorithm for Three-Phase Power Transformer Differential Protection Considering Effect of Ultra-Saturation Phenomenon Based on Discrete Wavelet Transform

2018 ◽  
Vol 20 (1) ◽  
Author(s):  
Bahram Noshad
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Power Transformer ◽  
Discrete Wavelet ◽  
Inrush Current ◽  
Differential Protection ◽  
Inductive Load ◽  
Saturation Phenomenon ◽  
Three Phase ◽  
Transformer Differential Protection

Abstract One of transient phenomena that lead to the false trip of the power transformer differential protection during the energization of a loaded power transformer is the ultra-saturation phenomenon. This paper presents, at first, a new algorithm for three-phase power transformer differential protection considering effect of the ultra-saturation phenomenon based on Discrete Wavelet Transform (DWT). To model the ultra-saturation phenomenon, the nonlinear characteristic of the transformer core and the effect of the saturation of the current transformers are taken into account. It is assumed that the load of the transformer is a resistive and inductive load. In this algorithm, the ultra-saturation phenomenon, the external and internal faults of power transformer and the magnetic inrush current are simulated. To distinguish between these phenomena, appropriate criteria using DWT by the use of standard deviation of coefficients are presented. Also, one of the most important criteria for the digital relays is the time for making a decision. Thus, to determine the time of decision, the experimental results will be presented.

scholarly journals Wavelet Transform Based Fault Identification and Reconfiguration for a Reduced Switch Multilevel Inverter Fed Induction Motor Drive

Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1023
Author(s):  
Arigela Satya Veerendra ◽  
Akeel A. Shah ◽  
Mohd Rusllim Mohamed ◽  
Chavali Punya Sekhar ◽  
Puiki Leung
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Multiresolution Analysis ◽  
Short Circuit ◽  
Open Circuit ◽  
Multilevel Inverter ◽  
Fault Identification ◽  
Discrete Wavelet ◽  
The Novel ◽  
Inverter Topology

The multilevel inverter-based drive system is greatly affected by several faults occurring on switching elements. A faulty switch in the inverter can potentially lead to more losses, extensive downtime and reduced reliability. In this paper, a novel fault identification and reconfiguration process is proposed by using discrete wavelet transform and auxiliary switching cells. Here, the discrete wavelet transform exploits a multiresolution analysis with a feature extraction methodology for fault identification and subsequently for reconfiguration. For increasing the reliability, auxiliary switching cells are integrated to replace faulty cells in a proposed reduced-switch 5-level multilevel inverter topology. The novel reconfiguration scheme compensates open circuit and short circuit faults. The complexity of the proposed system is lower relative to existing methods. This proposed technique effectively identifies and classifies faults using the multiresolution analysis. Furthermore, the measured current and voltage values during fault reconfiguration are close to those under healthy conditions. The performance is verified using the MATLAB/Simulink platform and a hardware model.

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