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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]

This paper presents a new method for busbar differential protection based on the instantaneous power concept. In order to do so, the instantaneous power per phase of each network element connected to the busbar is computed by using the instantaneous current values and a voltage memory action strategy. The performance of the proposed technique is compared to one of the traditional instantaneous-current-based differential protection algorithms, which is widely used by manufacturers of commercial relays. Both internal and external faults, as well as evolving external-to-internal faults, were simulated in a power substation with double-bus single-breaker configuration using the software ATPDraw. The obtained results reveal that the proposed algorithm is twice or more faster than the traditional instantaneous-current-based algorithm for most of the internal and evolving external-to-internal faults, while ensuring secure operation for external ones even when severe current transformer (CT) saturation takes place, through a new harmonic power restraint strategy. Also, since the proposed method provides faster fault detection time, the requirements for CT time to saturate may be alleviated, guaranteeing correct operation even in the case of early CT saturation. [ABSTRACT FROM AUTHOR]

This paper presents a new wavelet-based busbar differential protection algorithm, named as 87BW function. The instantaneous current-based differential protection fundamentals are taken into account and the well-known 1-out-of-1 and 2-out-of-2 tripping logics are mapped into the wavelet domain. Operating and restraint wavelet coefficients energy of currents are computed, regarding station configuration and bus zones boundaries. Thereby, the proposed 87BW function can be properly used in both static and dynamic busbar configuration. Its performance was evaluated through EMTP-based simulations of faults in a 230 kV power substation with double bus single breaker configuration. The obtained results reveal it provides ultra-high-fast trip for internal and evolving external-to-internal faults, guaranteeing security for normal through-load and external faults as well, even in the case of early and severe current transformer saturation. [ABSTRACT FROM AUTHOR]

This study proposes a new concept of transmission line differential protection based on an alternative alpha plane of incremental complex power, where the restraint characteristic is simply defined as its left‐half‐plane, so that no settings are required to define it. As the incremental complex power is evaluated per phase, the proposed algorithm is inherently phase segregated, not requiring additional faulted phase selection logics. A simple harmonic restraint strategy along with an external fault detection logic provides security for external faults with current transformer saturation. Aiming to evaluate the performance of the proposed algorithm, a wide variety of fault scenarios are simulated for a 500 kV transmission line 200 km long using the Alternative Transients Program. The obtained results reveal the proposed algorithm provides a fast and reliable line protection, being robust against variations in fault parameters, sources strength and loading conditions, as well as power swing situations and line energisation manoeuvres. Accordingly, one can suppose the proposed algorithm might be successfully used in numerical transmission line relaying. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a novel filter design technique based on the maximal overlap discrete wavelet transform (MODWT). Time and frequency response of the designed filters are compared to the ones of traditional discrete Fourier transform (DFT) based filters. The obtained results show improvements on response speed when comparing to full cycle traditional filters and improvements on frequency response when compared to half cycle traditional filters. According to these characteristics, the designed filter may be used in secure high-speed distance protection, since it provides fast relay operating times, without compromising their frequency response. [Copyright &y& Elsevier]