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This paper revisits the analysis of the well-known infeed effect on transmission lines distance protection. A new adaptive algorithm to overcome this drawback is proposed, which requires solely impedance data and the operational status of power apparatus to perform overreaching distance zones settings. A comparison of the proposed strategy and the traditional one is performed. The obtained results demonstrate that the proposed settings ensure the correct operation of overreaching zones. Thereby, the backup coverage is improved significantly, besides avoiding distance zones overlapping between adjacent lines. It reveals the proposed strategy usefulness and value from the practical point of view, since it can be implemented with technology readily available on the market. [ABSTRACT FROM AUTHOR]

An approach to detect the secondary arc extinction is proposed here for single-phase auto-reclosing of non-compensated transmission lines. It consists on the analysis of the line side voltage phasors in the modal domain to safely and rapidly identify the presence and the extinction of secondary arc in the line. The procedure can also determine the arc re-ignition if it occurs during the line dead time. Since the proposed approach requires only the voltage phasors at one line terminal, it can be easily implemented in existing Intelligent Electronic Devices (IEDs) with no additional hardware or equipment requirement. Data from the Brazilian Power Grid were used to generate the case studies through the Electromagnetic Transients Program (EMTP). Moreover, field recordings were used to validate the proposed approach. A qualitative comparison with existing methods was accomplished and the obtained results reveal the proposed scheme efficiency, reliability and robustness. [ABSTRACT FROM AUTHOR]

This paper revisits the generalized alpha plane (GAP) formulation applied to differential protection of multi-terminal apparatus. The GAP formulation is improved by aiming for three main goals: 1) control over the internal fault settlement region (FSR); 2) enabling a simple operation characteristic instead of a restraint characteristic; and, 3) The adjustments are not dependent to the device type. For this purpose, the GAP formulation is redefined in terms of two settings, which transform the FSR into a circumference with a controllable center and radius. Thereby, a circular operation characteristic with an adjustable radius is enabled around the FSR, for to improve security. To validate and test the performance of the improved GAP, numerous computer simulations have been carried out using Alternative Transients Program on different multi-terminal equipment (i.e., busbars, transmission lines, and power transformers). Furthermore, massive data analysis is held as a means to highlight the GAP's sensibility. The obtained results demonstrate a well-stable pre-fault point, a consistent circular FSR, and the effectiveness of the improved GAP even under severe conditions. [ABSTRACT FROM AUTHOR]