Evaluation of Lightning Impulse Test by Frequency Response Analysis

Valecillos, Baudilio; Ramírez, José Miguel

doi:10.1109/tdcla.2006.311421

Cited by 6 publications

(3 citation statements)

References 23 publications

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“…Major downside of interleave and inter-shield windings is the likelihood of occurrence of 'part winding resonance' [3], as high series capacitance makes them vulnerable to 'forced resonance', and input excitations, even in the form of a standard lightning impulse, can eventually force these windings to oscillate at their natural frequencies. A homogeneous winding, such as uniform interleaved winding [9,10] may further invite such unwanted resonances, as disk coils would normally possess a single natural frequency, and would collectively oscillate at a common resonate frequency [11][12][13]. This study suggests a practical approach to overcome the likelihood of cumulative resonance in homogeneous transformer windings by deliberately introduced variations in the natural frequencies of the disk coils through multi-graded self-capacitance of the disk coils.…”

Section: Introductionmentioning

confidence: 99%

Self‐capacitance grading approach to suppress winding resonance in EHV transformers under oscillatory terminal disturbances

De¹,

Bandyopadhyay

2018

High Voltage

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Interleaving of the high-voltage winding turns is a widely-accepted method for restraining the surge voltage stresses in extra high voltage (EHV) transformers. Reduction of voltage stresses under external surge is attributed by the increase in the self-capacitance of the interleaved winding disks. However, the apparent benefit of interleaving may be counterpoised by a significant decrease of natural frequency of windings, which in turn, may force a winding to resonate under external surges. Winding resonance is particularly noticeable when uniform interleaving is adopted for the whole winding, uniform interleaving attributes a unique natural frequency to all interleaved coils and consequently, the collective resonance of the winding disks is plausible. Uniform interleaving in large EHV transformers therefore leads to complications and the windings reportedly exhibit an unexpectedly poor surge voltage response because of such internal resonances. This study describes a novel concept termed as 'graded interleaving' for EHV transformer windings to overcome resonance and to achieve an improved response against surge voltage. The performance of the proposed winding was tested on a 132/33 kV two-winding transformer with a tap changer using EMTP(ATP) simulations with encouraging results. Manufacturing and real-time implementation feasibility of the winding were verified with transformer manufacturers.

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Section: Introductionmentioning

confidence: 99%

Self‐capacitance grading approach to suppress winding resonance in EHV transformers under oscillatory terminal disturbances

De¹,

Bandyopadhyay

2018

High Voltage

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“…FRA can be used to evaluate the state of a winding by mathematically comparing the transfer function [21,22] curves under normal and fault conditions and determine the type of fault using the correlation coefficient [23] and other statistical indicators. The exciting signal injected by SFRA is a series of sweep signals at different frequencies and a voltage amplitude of several volts; the exciting signal of IFRA is an aperiodic impulse that contains multi-frequency components and a voltage amplitude of several hundred volts.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Impulse Wave and Sweep Frequency Response Analysis Methods for Diagnosis of Transformer Winding Faults

Yang

Yong

2017

Energies

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Abstract:Monitoring of winding faults is the most important item used to determine the maintenance status of a transformer. Commonly used methods for winding-fault diagnosis require the transformer to exit operation before testing and an external exciting signal, whether the transformer is malfunctioning or not. However, if an overvoltage signal can be regarded as a broadband excitation source for fault diagnosis, then the interference caused by signal injection can be eliminated without the need for additional pulse or impulse signals. In this paper, a tapped transformer is designed and test platforms are built to compare winding diagnoses using the impulse wave and sweep frequency response analysis methods by recording voltage responses on both the high-and low-voltage sides and calculating the respective transfer functions. Based on comparison of statistical indicators, it is found that the sensitivities of both methods are similar for detecting conditions of winding-ground and winding-interlayer short circuits. It is concluded that it is feasible to use a transient overvoltage monitoring system for winding-fault diagnosis.

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“…Sometimes these levels can overcome the safety limits of the components, and the effects are temporary faults or permanent damages [17]. For these reasons, during the design stage of the converter, it is very important to simulate the indirect lightning effects and check the corresponding immunity levels [18][19]. When the test severity overcomes the strength of the converter components, a suitable protection device must be used [20].…”

mentioning

confidence: 99%

Protection From Indirect Lightning Effects for Power Converters in Avionic Environment: Modeling and Experimental Validation

Rimal

Reatti

Corti

et al. 2021

IEEE Trans. Ind. Electron.

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Evaluation of Lightning Impulse Test by Frequency Response Analysis

Cited by 6 publications

References 23 publications

Self‐capacitance grading approach to suppress winding resonance in EHV transformers under oscillatory terminal disturbances

Self‐capacitance grading approach to suppress winding resonance in EHV transformers under oscillatory terminal disturbances

Comparison of Impulse Wave and Sweep Frequency Response Analysis Methods for Diagnosis of Transformer Winding Faults

Protection From Indirect Lightning Effects for Power Converters in Avionic Environment: Modeling and Experimental Validation

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