scholarly journals Frequency Response Quality Index for Assessing the Mechanical Condition of Transformer Windings

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 29 ◽  
Author(s):  
Eugeniusz Kornatowski ◽  
Szymon Banaszak
Keyword(s):  
Frequency Response ◽  
Quality Index ◽  
Response Analysis ◽  
Test Results ◽  
Response Curves ◽  
Response Measurement ◽  
Response Quality ◽  
Mechanical Condition ◽  
Measurement Results

Frequency response analysis (FRA) is a popular method for assessing a transformer’s mechanical condition. The paper proposes a new method for interpreting the frequency response measurement results. The currently used numerical indices only give one value, which may be misleading in the analysis, while the proposed frequency response quality index (FRQI) tool analyses three separate features in the whole frequency range. The applied numerical calculations technique allows for estimations of not only the values of the average quality indices, but also locally for given frequency ranges of the analysed spectrum. It allows for determination of the problems that can be found in the active part of a transformer. The presented results come from three transformers, representing cases of typical faults. Two of them are from industry, while one was used for deformational tests in laboratory conditions. The proposed FRQI method showed its usefulness in FRA test results analysis and may be introduced into the automated assessment of such data. Each of the component parameters is sensitive to other types of differences observed between the compared frequency response curves, and may be used as a good quality detection tool.

scholarly journals Optimization of Transformer Winding Deformation Assessment Criterion Considering Insulation Aging and Moisture Content

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6491
Author(s):  
Qian Wu ◽  
Yizhuo Hu ◽  
Ming Dong ◽  
Bo Song ◽  
Changjie Xia ◽  
...  
Keyword(s):  
Moisture Content ◽  
Frequency Response ◽  
High Sensitivity ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Response Curves ◽  
Insulation Aging ◽  
Transformer Winding ◽  
Winding Deformation ◽  
Paper Insulation

Frequency response analysis is widely used to diagnose transformer winding deformation faults due to its high sensitivity, strong anti-interference capability, and equipment portability, but the results of frequency response analysis can be affected by insulation aging and moisture in the transformer, leading to errors in the diagnosis of winding deformation faults. Currently, there is no effective method to prevent such errors. This paper focuses on optimizing the criterion for diagnosing winding deformations when insulation aging and moisture are present. First, the winding frequency response curves of oil-paper insulation were determined by combining insulation aging and moisture tests of the oil-paper insulation with frequency response simulations of the transformer winding. Next, the winding deformation criterion predicting the likelihood and extent of errors diagnosing transformer winding deformations due to the insulation aging and moisture content is discussed. Finally, the corresponding criterion optimization method is proposed. The corresponding results show that insulation aging and moisture can lead to errors when using the correlation coefficient R criterion to diagnose the transformer winding deformations. Moreover, the possibility of winding deformation errors caused by the change of insulation state can be reduced by introducing the corresponding auxiliary criterion through comparing the capacitance change rate based on the frequency response method and that based on the dielectric spectrum method.

scholarly journals Frequency Response Modeling of Transformer Windings Utilizing the Equivalent Parameters of a Laminated Core

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2371 ◽  
Author(s):  
Konstanty Marek Gawrylczyk ◽  
Katarzyna Trela
Keyword(s):  
Frequency Response ◽  
Research Utilization ◽  
Power Transformer ◽  
Three Dimensional ◽  
Magnetic Core ◽  
Wide Frequency Range ◽  
Response Analysis ◽  
Response Curves ◽  
Transformer Winding ◽  
Response Modeling

The aim of the article is to present the method for modeling transformer winding inductance, taking into account the complex magnetic permeability and equivalent electric conductivity of the magnetic core. In the first stage of the research, a physical model of a 24-turn coil wound on the distribution transformer core was prepared. The Frequency Response Analysis (FRA) measurements of the coil were taken; then, the inductance of the coil as a function of frequency was calculated from the received frequency response curves. In the second stage, two-dimensional (2D) and three-dimensional (3D) computer models of the coil based on the finite element method (FEM) were established. In order to obtain the equivalent inductance characteristics of the winding modeled in 2D and 3D in a wide frequency range, the equality of the reluctance of the limbs and yokes in both models was assured. In the next stage of the research, utilization of the equivalent properties for the laminated magnetic material simulations was proposed. This outcome can be used to calculate the frequency response of the winding of the power transformer. The other obtained result is the method for modeling the resonance slope, which is visible on the inductance curve received from the FRA measurement.

scholarly journals The Influence of Capacitance and Inductance Changes on Frequency Response of Transformer Windings

2019 ◽  
Vol 9 (5) ◽  
pp. 1024 ◽  
Author(s):  
Szymon Banaszak ◽  
Konstanty Gawrylczyk ◽  
Katarzyna Trela ◽  
Patryk Bohatyrewicz
Keyword(s):  
Frequency Response ◽  
Uncertain Data ◽  
Test Method ◽  
Response Analysis ◽  
Test Results ◽  
Frequency Response Analysis ◽  
Comparison Results ◽  
The Given ◽  
The Relationship ◽  
Curve Shift

Frequency Response Analysis (FRA) is a test method used for assessment of mechanical condition of transformer active parts. Its biggest problem is the interpretation of test results, namely the relationship between scale of differences between compared curves and the decision for further operation of the given transformer. Very often visible differences between two FRA curves do not mean that there is a deformation in the winding. The cause of the curve shift may come from other elements of the transformer that influence inductive or capacitive parameters. This paper takes under consideration the influence of both capacitance and inductance changes on transformer frequency response (FR). The analysis is performed with the computer model of a transformer and also some experimental results are presented, showing the influence of capacitance and inductance changes on the FR of real transformers. The results of research showed that this influence may lead to misleading effects on the shape of FR characteristics. The paper presents an analysis that can be used in the assessment of FRA measurement, especially in the case of uncertain data comparison results.

scholarly journals Experimental Tests of Parameters Characterizing the Cooperation of Powered Roof Support Base and Floor of Low Bearing Capacity

2016 ◽  
Vol 61 (4) ◽  
pp. 937-948
Author(s):  
Józef Markowicz ◽  
Sylwester Rajwa ◽  
Stanisław Szweda
Keyword(s):  
3D Model ◽  
Experimental Tests ◽  
Base Pressure ◽  
Test Results ◽  
Support Set ◽  
Longwall Panel ◽  
Measurement Results ◽  
Measuring Instrumentation ◽  
Roof Support

Abstract Results of experimental tests aiming at determination of base pressure on the floor, carried out within “Geosoft” project, are presented. The tests included stand tests carried out with use of unique measuring instrumentation and special hydraulic cushion as well as tests of load of roof support set to load in operating longwall panel. The measurement results confirmed the necessity to consider the 3D model of cooperation of base and floor. Factors having impact on distribution of base pressure on the floor and its maximal value were identified, taking into account the test results.

Dynamic Characteristics Analysis and Topology Optimization of Column Based on Finite Element Method

2013 ◽  
Vol 721 ◽  
pp. 541-544
Author(s):  
Jing Chen ◽  
Ze Long Yang ◽  
Xian Xuan Li
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Frequency Response ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Response Analysis ◽  
Response Curves ◽  
Element Analysis ◽  
Column Structure

Aiming to improve the dynamic and static characteristics of a type of machining center column, the finite element modal analysis and harmonic response analysis of the column are performed, and this paper analyzes the dynamic characteristics of the column based on the first five mode shapes and natural frequencies of the column and the displacement - frequency response curves of the column. Topology optimization analysis of the column is performed with ANSYS, and the finite element analysis is performed on the column again after the column structure is improved based on the optimal distribution of material of the column structure and the design experience of column. The result shows that the first five natural frequencies of the column increase, the peak of the displacement - frequency response of the column decrease, and the dynamic characteristics are improved significantly.

Amplitude Frequency Response Analysis and Synthesis of Unfactored Transfer Functions

1964 ◽  
Vol 86 (1) ◽  
pp. 32-36 ◽  
Author(s):  
J. S. Ausman
Keyword(s):  
Frequency Response ◽  
Transfer Functions ◽  
Response Characteristic ◽  
System Stability ◽  
System Response ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Response Curves ◽  
Analysis And Synthesis ◽  
Amplitude Versus

A graphical method provides, without templates and without factoring, a means for rapidly estimating log-amplitude versus log-frequency response curves from transfer functions in their unfactored polynomial form. The technique can also be used to design or synthesize transfer functions which will produce a specified frequency response characteristic. Included is a graphical stability criterion for third and fourth-order systems which provides a quick check on system stability during the course of design or of analysis of the system response.

Research of Fault Type of Transformer Winding Based on Frequency Response Analysis

2013 ◽  
Vol 448-453 ◽  
pp. 2270-2273
Author(s):  
Xin Zhang ◽  
Xin Wang ◽  
Yi Hui Zheng ◽  
Li Xue Li ◽  
Li Dan Zhou ◽  
...  
Keyword(s):  
Frequency Response ◽  
Response Curve ◽  
Response Analysis ◽  
Frequency Response Curve ◽  
Frequency Response Analysis ◽  
Response Curves ◽  
Fault Type ◽  
Curve Change ◽  
Transformer Winding ◽  
Novel Method

In this paper, a novel method based on FRA is proposed to detect both the fault and the deformation type. Firstly, a model of the transformer winding is established based on the electrical properties of winding. Secondly, as the winding frequency response curve change in accordance with the change of the parameters of winding model, the rule of the variation of winding frequency response curve is drawn out based on the model above. Thirdly, the effect of various types of winding deformation on the changes of the parameters of transformer winding model is summarized. Finally, an experimental example of the diagnosis of deformation type is conducted on a testing transformer based on the analysis of frequency response curves, hence the validation of the correctness of the simulation results.

Sign in / Sign up

Export Citation Format

Share Document