Research on identification between inrush current and internal faults of power transformer based on H-S transform

2010 ◽  
Author(s):  
Shangbin Jiao ◽  
Huang Huang
Keyword(s):  
Power Transformer ◽  
Inrush Current ◽  
S Transform ◽  
Internal Faults

scholarly journals Wavelet Transform Implementation to Differentiate Inrush Current and Fault Current in Power Transformer

2020 ◽  
Vol 8 (5) ◽  
pp. 3041-3044
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Fast Fourier Transform ◽  
Power Transformer ◽  
Normal Faults ◽  
Inrush Current ◽  
Fault Current ◽  
Electrical System ◽  
Protection Circuit ◽  
Internal Faults

An electrical system is al complex network, to enhance power generation, transmission and distribution transformers play an important role. Power transformer is the heart of the electrical system. Even though electrical power is generated at lower rate in the coastal areas, it can be transmitted easily over hundreds of kilometer with the help of power transformer. So there must proper protection should given to power transformers. But in order to give the proper protection there should be proper discrimination between internal faults and inrush current. If there is no proper differentiation between faults and inrush current phenomena than the protection circuit will not trip when inrush current comes into the picture. But the protection circuit will trip at faster rate than the actual one when the normal faults or internal faults come into the picture. So there should be proper discrimination between inrush current and internal fault current so that the protection circuit will work properly. There are so many techniques available to get differentiation between inrush current and fault current. Fast Fourier transform is one of the method to differentiate between these two currents. Here we are using wavelet transform technique to get the difference between these two currents. The properties of the inrush current obtained from this technique are accurate and distinct from those obtained from the fast Fourier transform. The experimental set up is carried out in matlab simulink and results were discussed as shown below in results.

scholarly journals Designing A Protective Relay for Differential Protection of Power Transformers Using Clarks Transform and S Transform

2019 ◽  
Author(s):  
Javad Padam
Keyword(s):  
Power Transformer ◽  
Computational Cost ◽  
Power Transformers ◽  
Inrush Current ◽  
Differential Protection ◽  
Two Phase ◽  
Transient Phenomena ◽  
S Transform ◽  
Three Phase ◽  
Clarke Transformation

Given that power transformers are one of the most important components of each network, their protection is an important part that the power transformer errors must be accurately identified and distinguished from each other. Therefore, identification and differentiation of transient phenomena of power transformers, including internal and external errors and magnetic inrush current are essential. In this research, Clarke transform and S transform were used to distinguish between these phenomena that the proposed algorithm is very suitable in terms of three characteristics of accuracy, speed and computational cost. Initially, the simulation of internal, external errors and magnetic inrush current of the transformer was performed for different transformer scenarios. For this purpose, 1060 signal tests were performed under different conditions. Subsequently, the signals of differential current obtained by Clarke transformation and S transformation were analyzed and appropriate criteria were extracted for detecting the current of internal errors from external errors and inrush current. The simulated internal and external errors include three- phase, three-phase to ground, two- phase, two- phase to ground and phase to ground error. Simulations were performed using PSCAD software and implementation of the proposed algorithm in MATLAB environment. The results of this study prevent the unwanted performance of differential protection to prevent undesirable electrifying. It is clear that the description of transient phenomena is the first step towards improving new ideas and criteria for protection with the greater reliability of power transformer which can be controlled better such unusual conditions that are currently used in equipment and relay.

Evaluation of the Power Transformer Magnetizing Inrush Currents

2020 ◽  
Vol 10 (10) ◽  
pp. 20-32
Author(s):  
Aleksey A. KUVSHINOV ◽  
◽  
Vera V. VAKHNINA ◽  
Aleksey N. CHERNENKO ◽  
◽  
...  
Keyword(s):  
Power Transformer ◽  
Geomagnetic Disturbance ◽  
Inrush Current ◽  
Geomagnetic Disturbances ◽  
Disturbance Intensity ◽  
Magnetizing Inrush Current ◽  
Inrush Currents ◽  
Instantaneous Values ◽  
The Mathematical Model ◽  
Analytical Expressions

The mathematical model of a shell-core power transformer’s magnetization branch is substantiated. By using the model, analytical expressions for the magnetizing current instantaneous values under the conditions of geomagnetic disturbances can be obtained. Quantitative assessments of the magnetizing inrush current amplitudes and durations versus the geomagnetic disturbance intensity are obtained. The dynamics of the power transformer magnetic system saturation transient and changes in the magnetization inrush current amplitudes and durations after a sudden occurrence of geomagnetic disturbances are shown. The error of estimating the magnetizing inrush current amplitudes under geomagnetic disturbances is determined based on comparison with experimental data.

Inter-turn fault stability enrichment and diagnostic analysis of power system network using wavelet transformation-based sample data control and fuzzy logic controller

2021 ◽  
pp. 014233122110070
Author(s):  
Arunesh Kumar Singh ◽  
Abhinav Saxena ◽  
Nathuni Roy ◽  
Umakanta Choudhury
Keyword(s):  
Fuzzy Logic ◽  
Power System ◽  
Wavelet Transformation ◽  
Fuzzy Logic Controller ◽  
Power Transformer ◽  
Harmonic Distortion ◽  
Inrush Current ◽  
Data Control ◽  
Sample Data ◽  
Z Transformation

In this paper, performance analysis of power system network is carried out by injecting the inter-turn fault at the power transformer. The injection of inter-turn fault generates the inrush current in the network. The power system network consists of transformer, current transformer, potential transformer, circuit breaker, isolator, resistance, inductance, loads, and generating source. The fault detection and termination related to inrush current has some drawbacks and limitations such as slow convergence rate, less stability and more distortion with the existing methods. These drawbacks motivate the researchers to overcome the drawbacks with new proposed methods using wavelet transformation with sample data control and fuzzy logic controller. The wavelet transformation is used to diagnose the fault type but contribute lesser for fault termination; due to that, sample data of different signals are collected at different frequencies. Further, the analysis of collected sample data is assessed by using Z-transformation and fuzzy logic controller for fault termination. The stability, total harmonic distortion and convergence rate of collected sample data among all three methods (wavelet transformation, Z-transformation and fuzzy logic controller) are compared for fault termination by using linear regression analysis. The complete performance of fault diagnosis along with fault termination has been analyzed on Simulink. It is observed that after fault injection at power transformer, fault recovers faster under fuzzy logic controller in comparison with Z-transformation followed by wavelet transformation due to higher stability, less total harmonic distortion and faster convergence.

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