Transient Electromagnetic Fields Due to Switching Operations in Electric Power Systems

Ari, N.; Blumer, W.

doi:10.1109/temc.1987.304373

Cited by 24 publications

(5 citation statements)

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“…The electromagnetic fields can be calculated by analytical or numerical methods. The hertzian dipole [4], [9] or the analyt-0885-8977/$26.00 © 2010 IEEE Authorized licensed use limited to: STRATHCLYDE UNIVERSITY LIBRARY. Downloaded on June 22,2010 at 11:19:33 UTC from IEEE Xplore.…”

Section: Analytical and Fdtd Methods Of Field Calculationmentioning

confidence: 99%

“…On the reflections due to ground, using the ramp or the Hertzian method, separate techniques must be used to account for the reflections. For example [2], [6] used a method based on Fresnel reflection coefficients and recursive convolution, while [4], [5] used the image method. However, in the FDTD formulation it is a matter of specifying the conductivity, permittivity and permeability at the points, which lie within the ground region.…”

Section: B Reflections At the End Of Bus And Groundmentioning

confidence: 99%

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Computation of Transient Electromagnetic Fields Due to Switching in High-Voltage Substations

Musa

Siew

Judd

2010

IEEE Trans. Power Delivery

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Switching operations of circuit breakers and disconnect switches radiate transient electromagnetic fields within highvoltage substations. The generated fields may interfere and disrupt normal operations of electronic equipment. Hence, the electromagnetic compatibility (EMC) of this electronic equipment has to be considered as early as the design stage of substation planning and operation. Also, microelectronics are being introduced into the substation environment and are located close to the switching devices in the switchyards more than ever before, often referred to as distributed electronics. Hence, there is the need to re-evaluate the substation environment for EMC assessment, accounting for these issues. This paper deals with the computation of transient electromagnetic fields due to switching within a typical high-voltage air-insulated substation (AIS) using the finite-difference time-domain (FDTD) method.

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Section: Analytical and Fdtd Methods Of Field Calculationmentioning

confidence: 99%

Section: B Reflections At the End Of Bus And Groundmentioning

confidence: 99%

Computation of Transient Electromagnetic Fields Due to Switching in High-Voltage Substations

Musa

Siew

Judd

2010

IEEE Trans. Power Delivery

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“…One option is to use the Gaussian equation [26] as an approximation to the excitation function. Approximation of electrical discharge pulses can also be achieved through the use of two more equations: Wanninger's equation [20] and the double exponential equation [27]. These are presented along with their respective Fourier transforms in table 2.…”

Section: Comparison With Idealized Current Pulse Equationsmentioning

confidence: 99%

Partial discharge current pulses in SF₆and the effect of superposition of their radiometric measurement

Reid¹,

Judd²,

Stewart³

et al. 2006

J. Phys. D: Appl. Phys.

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The practical advantages of employing non-contact radio frequency (RF) methods for detecting partial discharges (PDs) in high voltage equipment have led to significant effort being focused on the diagnosis of electrical plants using RF techniques. This has particularly been the case for gas insulated substations, which use sulphur hexafluoride (SF6) as an insulating medium. One of the most important challenges facing RF diagnostics is the problem of relating the RF emissions to some measure of severity of the PD. Previous work has established that the amplitude or energy of RF signals radiated from a PD source is strongly dependent on the rate of change of current in the PD pulse. In this paper, measurements of PD current pulses in SF6 are presented for a point-plane configuration using an extremely wide bandwidth (13 GHz) measurement system. By this means, PD pulse shapes have been recorded with better resolution than has previously been possible and rise times have been measured with a high degree of accuracy. The results show a considerable variation in pulse shape, with the minimum rise time measured being 35 ps. With this high time-domain resolution, we have been able to distinguish features within the PD pulses that will affect the energy of the radiated RF signal. In particular, the current pulses tend to occur in bursts of up to ten individual pulses in as little as 1 ns, which will excite multiple RF signals in rapid succession. The effect of superposition of RF waveforms has been investigated by studying the variation in detected RF energy with respect to the time delay between PD pulses. It was found that when two PDs occur within a short period (< 150 ns) the combined energy of the resulting RF pulse has the potential to vary by ±30% of that resulting from two equivalent PD pulses with a wider pulse spacing (≫ 150 ns). In terms of a practical monitoring system concerned with order-of-magnitude variations; this is not considered to pose a major problem for the RF technique.

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“…As a particular way to conveniently describe the measured currents, the curve fitting method is widely used. The developed curve fitting models to approximate to the current waveforms include the Wanninger function [5], double exponential function [6,7] and Gaussian function [8]. These models are frequently utilized to investigate the discharge mechanisms and the radiated electromagnetic fields [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

A Novel Analytical Expressions Model for Corona Currents Based on Curve Fitting Method Using Artificial Neural Network

Fan¹,

Liu²,

Wei³

et al. 2015

PIER M

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Abstract-The analytical expressions for corona discharge currents are usually represented by the mathematic models based on curve fitting method. For the complex mechanisms, none of these currently models can describe a measured corona current with arbitrary waveforms. A novel curve fitting method using BP neural network (BPNN) technique is applied to describe the mathematic model of the corona currents in time domain. The analytical expressions for the currents can be established via extracting the weights and thresholds parameters of the trained BPNN. The expressions all have the same structure which has only four types of parameters, and the structure is independent of the corona current waveforms. The curve fitting for the measured corona currents with arbitrary waveforms by different models was carried out, and the results were analyzed, which indicate that the BPNN method performs best. Compared with the current expressions fitted by the double exponential function and Gaussian function, the expressions by BPNN can fit the current waveforms with the lowest mean square error (MSE) in time domain and the highest accuracy to spectra of the currents in frequency domain. The proposed method is suitable for establishing a unified analytical expressions model for corona currents with arbitrary shapes.

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Transient Electromagnetic Fields Due to Switching Operations in Electric Power Systems

Cited by 24 publications

References 1 publication

Computation of Transient Electromagnetic Fields Due to Switching in High-Voltage Substations

Computation of Transient Electromagnetic Fields Due to Switching in High-Voltage Substations

Partial discharge current pulses in SF₆and the effect of superposition of their radiometric measurement

A Novel Analytical Expressions Model for Corona Currents Based on Curve Fitting Method Using Artificial Neural Network

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Transient Electromagnetic Fields Due to Switching Operations in Electric Power Systems

Cited by 24 publications

References 1 publication

Computation of Transient Electromagnetic Fields Due to Switching in High-Voltage Substations

Computation of Transient Electromagnetic Fields Due to Switching in High-Voltage Substations

Partial discharge current pulses in SF6and the effect of superposition of their radiometric measurement

A Novel Analytical Expressions Model for Corona Currents Based on Curve Fitting Method Using Artificial Neural Network

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Product

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Partial discharge current pulses in SF₆and the effect of superposition of their radiometric measurement