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This paper is focused on the proposal and validation of a procedure to obtain the necessary data to model the magnetization curve of saturated core reactors as required for the voltage regulator device constituted by a parallel combination of an inductive saturated unit and a fixed capacitor bank. The methodology to model the nonlinear device is based on constructive parameters and information associated to the type of magnetic material utilized to build up the equipment. The results are expressed in terms of the relationship between the core flux and current values which are used to feed the ATPDraw time domain simulator. Computational studies are then carried out to find the reactive power absorbed by the reactor as a function of the applied voltage, and the theoretical results are compared to three prototypes having different ratings. The experimental results derived from 7kVAr-0.22kV, 600kVAr-13.8kV and 3MVAr-34.5kV products are then utilized to validate the saturation curve ATP representation through a comparative performance analysis of the absorbed reactive power with the voltage variation.

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Summary Using frequency domain approach, this paper focuses on a zero‐sequence harmonic filter model. The model is based on electromagnetic arrangement created through a three‐legged core construction and zigzag windings that provide a low‐priced, robust and efficient equipment to reduce zero‐sequence fundamental and harmonic distortion. The methodology adopted here provides a useful technique for evaluating the steady‐state operation of the filter with emphasis on its efficiency at reducing harmonics and at identifying the main constructive and electrical parameters of influence on the product performance. The representation is based on sequence harmonic transmittances that were found helpful in estimating the filter operational characteristics under both ideal and non‐ideal conditions. Furthermore, the effectiveness of the filter and its representation are fully validated using an equipment prototype and laboratory results. Copyright © 2014 John Wiley & Sons, Ltd.

Abstract. Power quality problems related to short or long time voltage variation have motived the search for voltage compensator techniques capable to provide dynamic voltage regulation to accomplish voltage supply levels in accordance with electrical energy agencies acceptable levels. Although one could recognize that a variety of products already offered in the market are capable of attending general electrical power system requirements the available technology comprises quite simple devices till very sophisticate ones. Having in mind the combination of simplicity, competitive cost, low maintenance need and an attractive performance at recovering the voltage deviations, then an electromagnetic concept to restore the desirable voltage within the established voltage levels is here proposed. The control strategy to be used can provide properties that enable this new device at proving the time response in accordance with the needs for long term and short term voltage variations. Concerning the proposed compensator physical topology it consists in extracting the necessary electrical power throughout a shunt transformer and the injection via a series unit. Besides the arrangement, the paper goes further by establishing a computational time domain model and a laboratory experiment to highlight the overall structure effectiveness at compensating voltage changes.