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.

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 Detection of Winding Axial Displacement of a Real Transformer by Frequency Response Analysis without Fingerprint Data

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 200
Author(s):  
Satoru Miyazaki
Keyword(s):  
Frequency Response ◽  
Transfer Functions ◽  
Axial Displacement ◽  
Lightning Strike ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
Transmission Tower ◽  
Three Phase ◽  
Transformer Winding ◽  
Fingerprint Data

Detection of the axial displacement of power-transformer winding is important to ensure its highly reliable operation. Frequency response analysis is a promising candidate in detecting the axial displacement. However, a method of detecting the axial displacement at an incipient stage without the need for fingerprint data has not been investigated yet. This paper focuses on resonances showing a bipolar signature in the transfer function of inductive interwinding measurement, which is sensitive to the axial displacement of the winding. Transfer functions in the inductive interwinding measurements of eight power transformers are measured before shipping to elucidate the features of resonances showing a bipolar signature. The measured resonances showing the bipolar signature can be divided into the “stair type” and the “crossing-curve type”. It is found that the grounding points in an inductive interwinding measurement determine the type of resonance showing the bipolar signature, irrespective of the type of winding, such as interleaved or multilayer winding, the winding arrangement, and the existence of stabilizing and tertiary windings. On the basis of this finding, a method of detecting the axial displacement of a transformer winding is proposed. In the proposed method, the amplitudes of the resonances among three phases are compared, or the three-phase pattern of the resonances is compared with normal patterns. Therefore, the proposed method is applicable to three-phase transformers without fingerprint data. The proposed method is applied to a real transformer that experienced a ground fault due to a lightning strike at a nearby transmission tower, and the effectiveness of the proposed method is confirmed.

A Tailored Learning Package for Multivariable Frequency Response Analysis

1984 ◽  
Vol 21 (2) ◽  
pp. 111-121
Author(s):  
R. Noel Wilson ◽  
C. McCorkell
Keyword(s):  
Frequency Response ◽  
Design Methods ◽  
System Response ◽  
Response Analysis ◽  
Analysis Program ◽  
Frequency Response Analysis ◽  
Graphical Displays ◽  
Alternative Techniques

The paper describes an interactive multivariable frequency response analysis program, suitable for undergraduate use. Nyquist Array (N.A.) and Inverse Nyquist Array (I.N.A.) design methods are provided, as are a range of graphical displays for system response investigation. Precompensation is available, using several alternative techniques.

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.

Influence of Speed Governors of Hydropower Stations on Frequency Stabilization of Fixed-Speed Wind Farm

2013 ◽  
Vol 14 (2) ◽  
pp. 189-198 ◽  
Author(s):  
Fawzi A. Rahman AL Jowder
Keyword(s):  
Power System ◽  
Frequency Response ◽  
Wind Farm ◽  
Transfer Functions ◽  
Frequency Stabilization ◽  
Response Analysis ◽  
Wind Gust ◽  
Frequency Response Analysis ◽  
Speed Governor ◽  
Hydropower Stations

AbstractThis paper uses a small power system, consisting of two hydropower stations and a fixed-speed wind farm as sources of power, to study the influence of type of speed governor of hydropower stations on the frequency stabilization of the fixed-speed wind farm. As an example, two types of speed governors are selected which are (1) mechanical-hydraulic speed governor and (2) electrical-hydraulic speed governor. Rest of the speed governors can be also examined following the same methodology presented in the research. Two transfer functions, which correspond to the two speed governors, are developed for each hydropower station. The overall transfer function of the test power system is developed, and different study cases are presented. The frequency response analysis of the different transfer functions is used to compare the two speed governors based on their ability to stabilize the frequency deviation of the fixed-speed wind resulting from electrical or mechanical disturbances in the power systems. Time-domain simulations under a mechanical disturbance, represented by a wind gust, and an electrical disturbance, represented by three-phase to ground fault, are performed to validate the results of the frequency response analysis.

Estimation and Reduction of Motor Input Surge Voltage using Frequency Response Analysis

2012 ◽  
Vol 132 (8) ◽  
pp. 630-637
Author(s):  
Toru Wakimoto ◽  
Yoshimitsu Takahashi ◽  
Norihito Kimura ◽  
Yukitoshi Narumi ◽  
Naoki Hayakawa
Keyword(s):  
Frequency Response ◽  
Response Analysis ◽  
Frequency Response Analysis

Identification of Trouble of Transformer by Frequency Response Analysis

2009 ◽  
Vol 129 (4) ◽  
pp. 517-525 ◽  
Author(s):  
Satoru Miyazaki ◽  
Yoshinobu Mizutani ◽  
Hiroshi Suzuki ◽  
Michiharu Ichikawa
Keyword(s):  
Frequency Response ◽  
Response Analysis ◽  
Frequency Response Analysis
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