Method of predicting transient-current patterns in transformers

Macfadyen, W.K.; Simpson, R.R.S.; Slater, R.D.; Wood, W.S.

doi:10.1049/piee.1973.0280

Cited by 15 publications

(2 citation statements)

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“…Eventually, we may consider a third group, where iron losses are just neglected. This simplification is justified when iron losses do not significantly influence the transient [47]- [54].…”

Section: Introductionmentioning

confidence: 99%

Analytical model of iron losses in power transformers

Elleuch¹,

Poloujadoff²

2003

IEEE Trans. Magn.

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We have improved a circuit model of transformers by defining a conductance whose losses will be close to the iron losses under any circumstance. Connecting a constant conductance cs in parallel with the main magnetizing inductance is very popular in the literature; however, it is acceptable only if the flux amplitude and frequency are reasonably constant during the time of operation, and if the value can be properly adjusted. Here, we replace cs with a nonlinear dynamic conductance cd , whose losses are a function of flux amplitude. This conductance is based on the concept of dynamical hysteresis. Its definition is such that it is determined by the same test results used for cs . Knowing the values of losses given by the manufacturer of the sheets, and the measured values of iron losses of a transformer, we can then analytically express the building factor as a function of the maximum flux density. We have applied the method to a three-leg 10-kVA transformer. It allows us to identify the cases when iron losses may be ignored, when they may be represented by a constant conductance, and when they must be represented by a nonlinear conductance.

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“…Eventually, we may consider a third group, where iron losses are just neglected. This simplification is justified when iron losses do not significantly influence the transient [47]- [54].…”

Section: Introductionmentioning

confidence: 99%

Analytical model of iron losses in power transformers

Elleuch¹,

Poloujadoff²

2003

IEEE Trans. Magn.

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“…Numerous research were carried out since early 1940's [1][2][3][4][5][6][7] to derive their mathematical f ormulations and explain these phenomena.…”

Section: Introductionmentioning

confidence: 99%

Digital Simulation of Magnetizing Inrush Currents in Three-Prase Transformers

Rahman

Gangopadhyay²

1986

IEEE Trans. Power Delivery

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An accurate simulation of magnetizing inrush currents is an important prerequisite for digital protection of power transformers.Generalized analytical expressions have been developed to simulate three-phase inrush currents based on sequence impedance and mutual coupling methods. The digitally simulated waveforms are compared with those obtained experimentally in a laboratory model transformer.There exists a reasonably close agreement between the computed and measured values.

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