scholarly journals Design of Hardware Setup Based on IEC 61850 Communication Protocol for Detection & Blocking of Harmonics in Power Transformer

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8284
Author(s):  
Abdul Azeem ◽  
Majid Jamil ◽  
Shamimul Qamar ◽  
Hasmat Malik ◽  
Rayees Ahmad Thokar

In this paper, the authors have developed a hardware model for blocking even and odd harmonics of a power transformer. In the proposed hardware model, intelligent differential & over-current relays are used for the blocking of harmonics of a power transformer. The harmonic restraint function on the differential relay (7UT61) prevents the relay from tripping during transformer magnetizing inrush current. However, the over-current relays which are used for back up protection does not have a harmonic restraint element, and over-current relay trips due to magnetizing inrush current, causes unwanted interruptions and power failures. The establishment of harmonic blocking scheme for over-current protection in power transformers is an important finding of this research study. IEC61850 standard-Based GOOSE (Generic Object Oriented Substation Event) applications used in power transformer protection for fast detecting and clearing of faults is an interested study presented in the proposed work.

Author(s):  
Azniza Ahmad ◽  
Mohammad Lufti Othman ◽  
Kurreemun Khudsiya Bibi Zainab ◽  
Hashim Hizam

Power transformer is the most expensive equipment in electrical power system that needs continuous monitoring and fast protection response. Differential relay is usually used in power transformer protection scheme. This protection compares the difference of currents between transformer primary and secondary sides, with which a tripping signal to the circuit breaker is asserted. However, when power transformers are energized, the magnetizing inrush current is present and due to its high magnitude, the relay mal-operates. To prevent mal-operation, methods revolving around the fact that the relay should be able to discriminate between the magnetizing inrush current and the fault current must be studied. This paper presents an Artificial Neural Network(ANN) based differential relay that is designed to enable the differential relay to correct its mal-operation during energization by training the ANN and testing it with harmonic current as the restraining element. The MATLAB software is used to implement and evaluate the proposed differential relay. It is shown that the ANN based differential relay is indeed an adaptive relay when it is appropriately trained using the Network Fitting Tool. The improved differential relay models also include a reset part which enables automatic reset of the relays. Using the techniques of 2nd harmonic restraint and ANN to design a differential relay thus illustrates that the latter can successfully differentiate between magnetizing inrush and internal fault currents. With the new adaptive ANN-based differential relay, there is no mal-operation of the relay during energization. The ANN based differential relay shows better performance in terms of its ability to differentiate fault against energization current. Amazingly, the response time, when there is an internal fault, is 1 ms compared to 4.5 ms of the conventional 2nd harmonic restraint based relay.


2020 ◽  
Vol 10 (10) ◽  
pp. 20-32
Author(s):  
Aleksey A. KUVSHINOV ◽  
◽  
Vera V. VAKHNINA ◽  
Aleksey N. CHERNENKO ◽  
◽  
...  

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.


Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4616
Author(s):  
Chen Wei ◽  
Xianqiang Li ◽  
Ming Yang ◽  
Zhiyuan Ma ◽  
Hui Hou

The remanence (residual flux) in the core of power transformers needs to be determined in advance to eliminate the inrush current during the process of re-energization. In this paper, a novel method is proposed to determine the residual flux based on the relationship between residual flux and the measured magnetizing inductance. The paper shows physical, numerical, and analytical explanations on the phenomenon that the magnetizing inductance decreases with the increase of residual flux under low excitation. Numerical simulations are performed by EMTP (Electro-Magnetic Transient Program) on a 1 kVA power transformer under different amounts of residual flux. The inductance–remanence curves are nearly the same when testing current changes. Laboratory experiments conducted on the same transformer are in line with the numerical simulations. Furthermore, numerical simulation results on a 240 MVA are reported to demonstrate the effectiveness of the proposed method.


2019 ◽  
Vol 8 (3) ◽  
pp. 7627-7630

This paper presents wavelet transform method for the analysis of differential currents of power transformer which can act as an accurate classifier between magnetizing inrush current and internal faults to avoid the needless tripping of circuit breaker. The differential protection scheme occasionally mal – operate whenever magnetizing inrush occurs in power transformer. The aim is to reduce the rate and time duration of undesired outages of power transformer. This includes the necessities of reliability with zero mal – operation of differential relay. The result shows higher operating speed with less fault clearing time. Wavelet Transform is employed for the analysis of transient signals under various conditions, which extracts data from signals in time and frequency domain simultaneously. The simulation is done in MATLAB environment.


2018 ◽  
Vol 7 (4.5) ◽  
pp. 126 ◽  
Author(s):  
Mudita Banerjee ◽  
Dr. Anita Khosla

This paper presents the second harmonics present in the primary current of a power transformer at different conditions using Fast Fourier Transform and Total Harmonic Distortion techniques to analyze the inrush condition and to distinguish it with fault condition of a power transformer. Result shows that the 2nd harmonic content is pre-dominant in inrush condition of primary current of the power transformer. It is observed that there are significant differences amongst the parameters found during inrush condition, normal condition and internal fault condition which are useful in the identification of magnetizing inrush current of power transformer. The simulation is done in MATLAB/SIMULINK. 


Author(s):  
Nassim A. Iqteit ◽  
Khalid Yahya

<p class="p1">An application of phase-angle-difference based algorithm with percentage differential relays is presented in this paper. In the situation where the transformer differential relay is under magnetizing inrush current, the algorithm will be utilized to block the process. In this study, the technique is modeled and implemented using Simulink integrated with MATLAB. The real circuit model of power transformer and current transformers are considered in the simulation model. The results confirmed the effectiveness of the technique in different operation modes; such as, magnetizing inrush currents, current transformers saturation and internal transformer faults.</p>


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