scholarly journals Fault detection using FRA in order to improve the aging model of power transformer

2020 ◽  
Vol 33 (3) ◽  
pp. 413-427
Author(s):  
Sasa Milic ◽  
Denis Ilic ◽  
Milan Ponjavic
Keyword(s):  
Fault Detection ◽  
Current Practice ◽  
Power Transformer ◽  
Power Transformers ◽  
Response Analysis ◽  
Test Results ◽  
Frequency Response Analysis ◽  
Aging Model ◽  
Mechanical Deformations ◽  
The Impact

Power transformers are constantly exposed to mechanical, thermal and electrical stresses during operation. In this paper, the authors propose an improved aging model of power transformers by adding the impact of mechanical deteriorations. In the current practice, the mechanical deformation and dislocation of the windings and core are not sufficiently distinguished as components that influence the aging of the transformer. Hence, the current aging model was expanded with a functional block that contains several typical failures in order to emphasize their impact on the lifetime of transformers and their aging as well. The authors used the Frequency Response Analysis (FRA) method for the fault detection and location of the mechanical deformations of its active parts. The correlation function is used to determine the level of the detected failure. All presented test results are obtained in real exploitation conditions.

scholarly journals Application of Frequency Response Analysis for in-service power transformers

2017 ◽  
Vol 20 (K1) ◽  
pp. 58-66
Author(s):  
Dinh Anh Khoi Pham
Keyword(s):  
Frequency Response ◽  
Power Transmission ◽  
Power Transformer ◽  
International Standards ◽  
Power Transformers ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Frequency Responses ◽  
Measured Frequency ◽  
Transformer Winding

CIGRE, IEC and IEEE have recently approved the technique of Frequency Response Analysis (FRA) as an application tool for diagnosis of mechanical failures in power transformer’s active part, i.e., windings, leads and the core. The diagnosis is based on the discrepancy between frequency responses measured on power transformers mainly at different time points. In Vietnam, utilities such as Power Transmission Companies and Power Corporations are investigating this technique for application on their power transformers. Mechanical failures in power transformers cause changes on measured frequency responses starting from a medium frequency range, from several hundreds of Hz or tens of kHz depending on transformer/winding type and power. For a reliable diagnosis, the understanding of transformer/winding structure on measured frequency responses is of importance; thus, the international standards suggested the simulation approach with physical distributed transformer circuits should be exploited. The development of physical distributed circuits of power transformers normally needs availability of internal transformer structure and material properties for an analytical approach. However, for in-service power transformers, this task is challenging since the required data are not available. For a feasible application of the simulation based FRA interpretation, this paper introduces an investigation on the development of a distributed equivalent circuit of an in-service 6.5 MVA 47/27.2 kV Yd5 power transformer. The result of this investigation is a feasible approach in determining electrical parameters in a physical distributed circuit, which supports analysis of frequency responses measured at transformer terminals for real application on in-service power transformers of utilities.

scholarly journals The investigation of frequency response analysis for power transformers winding condition

2019 ◽  
Vol 139 ◽  
pp. 01023
Author(s):  
Artyom Nazarov ◽  
Vitaliy Savelev ◽  
Dennis Frogh
Keyword(s):  
Frequency Response ◽  
Distribution Systems ◽  
Short Circuit ◽  
Mechanical Deformation ◽  
Power Transformers ◽  
Diagnostic Tools ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Electrical Transmission ◽  
The Impact

In modern electrical transmission and distribution systems, power transformers are critical components within the network. In the event that a failure occurs in service, the impact can be far reaching. The majority of mechanical deformation within power transformers is due to short circuit faults. The ageing transformer population increases the likelihood of failure so a reliable diagnostic tools required to determine the remaining life of these assets. Although, frequency response analysis (FRA) has been recently recognized as the most reliable detection tool for mechanical deformation in transformers, in the event of minor fault, the current FRA interpretation approach may not able to detect any variations between healthy and faulty FRA signatures. This paper focuses on FRA tests for power transformer and interpretation of obtained FRA signatures.

scholarly journals FRA Diagnostics Measurement of Winding Deformation in Model Single-Phase Transformers Made with Silicon-Steel, Amorphous and Nanocrystalline Magnetic Cores

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2424
Author(s):  
Maciej Kuniewski
Keyword(s):  
Frequency Response ◽  
Power Transformer ◽  
Amorphous Material ◽  
Silicon Steel ◽  
Frequency Characteristics ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Power Losses ◽  
Electrical Power System ◽  
The Impact

The power transformer is a key object in the electrical power system. The working principle hasn’t changed since its discovery. The main work nowadays is focused on the rising of the reliability of transformers and lowering power losses. The replacement of new materials instead of conventionally used ones can provide a solution. This procedure can improve factors, like a reduction of power losses, but also influence others normally neglected, like proper work in higher frequencies. The article presents the measurement results of the frequency characteristics of model test coils made with different magnetic materials cores (silicon steel, amorphous material, and nanocrystalline material), the measurements based on the sweep frequency response analysis (SFRA) method used for the determination of chosen frequency characteristics. The analysis presents the impact of different coil deformation levels on frequency characteristics. Results show that the replacement of conventional silicon steel with thinner high permeability materials can modify the state-of-the-art frequency response analysis (FRA) interpretation guidelines. The replacement of a new type of magnetic material as a magnetic core in the existing design of power transformer should lead to a full analysis of its behavior in the high-frequency domain.

Optical Frequency-Response Analysis for Power Transformer

2020 ◽  
pp. 1-1
Author(s):  
Guo-Ming Ma ◽  
Yunpeng Liu ◽  
Yabo Li ◽  
Xiaozhou Fan ◽  
Ce Xu ◽  
...  
Keyword(s):  
Frequency Response ◽  
Power Transformer ◽  
Response Analysis ◽  
Optical Frequency ◽  
Frequency Response Analysis

scholarly journals SFRA, Detect of Winding Deformation in Power Transformer

2020 ◽  
Vol 9 (5) ◽  
pp. 1392-1395
Keyword(s):  
Frequency Response ◽  
Power Transformer ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Sweep Frequency ◽  
Cause Analysis ◽  
Root Cause ◽  
Input And Output ◽  
Voltage Signal ◽  
Hidden Fault

The sweep frequency response analysis is extensively used technique for detect hidden fault and condition monitoring of power transformer. The operation is administered by supply a coffee voltage signal of varying frequencies to the transformer windings and measuring both the input and output signals. These two signals give the specified response of the ratio is named the transfer function of the transformer from which both the magnitude and phase are often obtained. Frequency response is change as measured by SFRA techniques may indicate a phase transition inside the transformer, then causes of fault identified and investigation is required for root cause analysis.

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