Operational Inductances of Turbine Generators; Test Data Versus Finite-Element Calculations

Dougherty, J. W.; Minnich, S. H.

doi:10.1109/tpas.1983.317836

Cited by 18 publications

(6 citation statements)

References 17 publications

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“…They reveal much about the physical nature of the internal magnetic and induced-current fields. This is a noticeable trend in recent literature on SSFR methods [12,13,14], particularly in conjunction with finite-element computations, and it represents a strong supporting argument for the frequency-response view of machine operation. That is the approach adopted in this paper, so that discussion generally will not involve terminal or circuit parameters, though they will appear in later work.…”

Section: Standstill Frequency-response Methodsmentioning

confidence: 77%

“…The main alternative methods for determining parameters, of interest at the present time, are (a) sudden short circuit [6] (b) stator-excited flux decay [7] (c) stator direct-current flux decay [8] (d) standstill frequency response [9] (e) on-line frequency response [10] (/) magnetic field computation [11,12,13,14] Of these, (a)-(e) are of course test procedures, while (/) is a theoretical approach. Tests (a), (b) and (e) are made with the machine rotating at rated speed, but (c) and (d) are standstill tests.…”

Section: Determination Of Turbogenerator Parametersmentioning

confidence: 99%

“…In recent years, the standstill frequency-response (SSFR) method has been extensively researched [2,4,9,11,12,13,14,19,22], largely stimulated by EPRI [15], and has undoubtedly become well established and important. It scores well on points (i)-(i v X particularly in providing information about the q axis, which is perceived to be a vital requirement.…”

Section: Determination Of Turbogenerator Parametersmentioning

confidence: 99%

“…These and other problems have been discussed by several researchers [5,9,11,12,13,14,19,22]. While there is evidently much work that can yet be done to appraise the method itself, as well as examining the implications of the results that it provides, it nevertheless appears established [4] that it can rival any alternative as a means of predicting transient machine performance following a system disturbance.…”

Section: Determination Of Turbogenerator Parametersmentioning

confidence: 99%

“…There are full-length continuous Duralumin wedges on the rotor, over copper damper strips, and this structure is interesting because its potentially high level of damping effect is now widely thought to be much under-represented in standstill tests. This is due in part to the high contact resistance between wedges and rotor (particularly marked when an aluminium surface is involved) which occurs in the absence of the high contact pressure created by centrifugal loading at normal running speed [11,12,14,22]. There is another complication with Nanticoke, due to the high permeability of its magnetic steel retaining rings at low excitation level [12,22].…”

Section: Contact Resistance and End Effectsmentioning

confidence: 99%

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Standstill micromachine for turbogenerator parameter studies

Harris

Bayindir

Jack

1987

IEE Proc. C Gener. Transm. Distrib. UK

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A micromachine is described for use in studies of standstill (particularly frequencyresponse) test methods for obtaining the transient impedance parameters of a tubogenerator. The severe design compromises associated with dynamic micromachines are completely avoided, rotor induced-current field and magnetic nonlinearity being correctly scaled. Advantages for the micromachine are listed and a detailed specification provided. First tests, in open-circuit field configuration, have shown the effect of surface contact resistance of aluminium wedges to be very pronounced, as is coming to be recognised in turbogenerator studies. Tests with wedges removed are compared with field computations, and with new data (obtained from installed probes) on the measured effectiveness of inducedcurrent paths in wedges and teeth. Standstill frequency-response measurements are possible in the micromachine up to 20% current, contrasting with 0.5% in a turbogenerator. Measurements of operational inductance and transfer function, over a full frequency range, thus show for the first time the changes that occur as excitation increases above the low-B range of magnetic nonlinearity. It becomes clear that the standard procedure for adjusting only the mutual branches of the d-and g-axis equivalent circuits, to allow for this nonlinearity, is inadequate. = scale factor of length = pitch factor of stator winding = scale factor of magnetic saturation density = scale factor of time List (for B E f H Us) if of symbols definition of per-unit system, see Sections 3.2 and 4.) = magnetic flux density = electric field strength = frequency 0 = operational transfer function (see eqn. 9) = magnetic field strength = Laplace transform of d-axis stator current = field current = base stator phase current (peak rated value) = base field current = current density = distribution factor of stator winding Paper 5137C (PI), first received on 6th May and in revised form 22nd October 1986 Prof. Harris and Dr. Jack are with the = d-axis mutual inductance L aq =

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Section: Standstill Frequency-response Methodsmentioning

confidence: 77%