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In the power grid, various conditions may occur that saturate the core of a current transformer. Saturation of the protection core of the current transformers can cause a malfunction in the protection relays. To prevent malfunction of the protection relays caused by the current transformer saturation, software and hardware methods can be used. In the software method changes in the protection relay algorithm are used. In the hardware method special devices are used. A new hardware method is presented here, which uses compensation to prevent the occurrence of current transformer saturation. In the proposed method, compensation is done by controlling an applied voltage to the current transformer secondary terminals using negative resistance. The proposed method, despite its simplicity and cost-effectiveness, has good performance in preventing saturation in various conditions. The high reliability in terms of the risk of secondary open circuit and its application in various saturation conditions, even in the case of severe saturation are the main advantages of the proposed method. Also, the proposed method does not produce distortion in the transformation of high-order harmonics by the current transformer. To verify the effectiveness of the proposed method, prototype design and construction have been performed. The simulation and experimental results of laboratory tests have been presented and analysed. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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