Journal of Advances in Engineering Sciences

Anuprita Sandeep Mishra ¹, Ganga Agnihotri ², N. P. Patidar ²

Affiliations
1 Maulana Azad National Institute of Technology, Bhopal, IN
2 Dept. of Electrical Engg., Maulana Azad National Institute of Technology, Bhopal, IN

Abstract

Electricity transmission and wheeling service pricing are becoming a more complex and more important task with the ongoing deregulation of electric power industry. In a competitive electricity market, transmission services have to be classified into two categories - transmission service and wheeling service. As distributed generation (DG) becomes more widely deployed in transmission system as well as in distribution networks to fulfill the demand in support of traditional generation, makes the transmission and wheeling pricing complicated. In this context authors have reviewed number of transmission / wheeling pricing methodologies with/without considering DG. In conjunction with traditional methods of pricing new methods were also reviewed which takes into account the pricing of both active and reactive powers because in few DG technologies reactive power flow direction becomes more important. Authors also reviewed the literature furnishing comparison of pricing methods related to DG. Specifically comparisons of MW-mile method based methodologies have been explored. In addition authors have discussed the Indian pricing methodology and inevitability of perfection.

Keywords

Dispersed Generation, Embedded Cost, Marginal Cost and Incremental Cost, Supplementary Cost.

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Ganga Agnihotri ¹, R. K. Khare ²

Affiliations
1 Dept. of Electrical Engg, Maulana Azad National Institute of Technology, Bhopal, IN
2 Electrical Engineering Department, LNCT, Bhopal, IN

Abstract

The paper presents normalized eddy current loss curve for ferromagnetic plates of finite thickness, giving variation of normalized loss, denoted as (loss factor)L with plate relative thickness, d/δ_L where d represents plate half thickness and δ_L signifies depth of penetration used under limiting nonlinear theory.

Graphical solution approach, ignoring the effect of harmonics of field quantities has been used to solve Maxwell’s field equation for thin iron plates subjected to sinusoidal magnetizing force at the surface, commonly denoted as SHS condition. Step function B₁-H approximate has been used for the magnetic characteristic of the plate material; and the result of graphical solution represented in the form of normalized eddy current loss and power factor curves. The appended eddy current loss curve has been shown useful for predicting eddy current loss in thin iron plates of varied electrical and magnetic properties, subjected to SHS condition. The result of the predicted values of eddy current loss have been compared with the corresponding test results for core losses and the two results are shown to be in close agreement within engineering accuracy for plates with relative plate thickness ≥ 0.40.

The application of the normalized eddy current loss has been attempted for predicting eddy current loss in thin iron plates subjected to the other boundary condition of the magnetic field at the surface, that is, sinusoidal current density at the surface, denoted as SJS condition and the results obtained have been compared with the corresponding test results for core losses. Surprisingly it has been found that the two results agree with each other within ± 14 percent for much thinner plates with relative plate thickness ≥ 0.28.

As such, the core losses in thin as well as thick iron plates subjected to two boundary conditions of magnetic field at the surface, namely, SHS and SJS can be assessed in the design office from the normalized eddy current loss which embodies frequency, resistivity, surface magnetizing force, Hs, saturation flux-density, Bs and plate half thickness. The power factor curve, appended can be utilized for calculating the power factor of the exciting winding circuit reflected by the magnetic circuit.

Keywords

Normalized Eddy Current, Loss Curve for Ferromagnetic Plates, Harmonics, SHS Conditions.

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