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This study describes the hardware implementation of a fast adaptive single-phase auto reclosing algorithm based on voltage harmonic content measurement. The proposed algorithm classifies the fault type, preventing reclosing onto permanent fault, and identifies the arc extinction instant, adjusting dead-time to implement reclosing with granted success. The hardware was connected to the Real Time Digital Simulator (RTDS) to perform tests in hardware-in-the-loop (HIL) with a protective relay. The studied system is based on a 500 kV transmission line of the Brazilian electrical power system and eventually real case oscillograms were tested. The algorithm performance was validated with previous software development. However, in the present document we highlight the importance to implement hardware test, as operational limits can only be identified in this last testing stage. Robustness of proposed algorithm based on low-order voltage harmonic content was proved with oscillograms’ tests.

Esse artigo propõe uma alternativa à metodologia hardware-in-the-loop de simulação em malha fechada denominada de software-in-the-loop para ensaios de sistemas de proteção, sendo exemplificado com o ensaio de um sistema de proteção diferencial de barras de baixa impedância. A primeira metodologia foi implementada através do simulador digital em tempo real RTDS juntamente com os relés físicos, enquanto que na segunda utilizou-se o software ATP e o relé foi modelado com a linguagem MODELS. Para comparação e validação dessa proposta realizou-se o ensaio composto por diversos casos em ambas metodologias, comparando o comportamento do sistema de proteção em cada uma delas.

This study presents the application of single-phase and three-phase adaptive reclosing method for transmission lines using a commercial protection relay. The method ensures the application of the automatic reclosing just after the extinction of a transient fault, the blocking of the automatic switching and, subsequently, the three-phase tripping for permanent faults. The study describes the proposed method implementation in a commercial relay. To represent both transient and permanent faults, oscillograms of real cases were used. The contributions of this work are the method to test the new algorithm in a commercial hardware, the distinction between transient and permanent faults and the detection of transient fault extinction through adaptive algorithms using commercial equipment.

This study presents a new phase selector algorithm and fault type classification for very long transmission lines, known as the half-wavelength lines (HWL). For this work, the Clarke components variation rate method applied to current magnitudes was used. The method was implemented in a real-time digital simulation hardware-in-the-loop (HIL) test environment. We applied different fault types at each 5% line length, obtaining Clarke component current phasors. The proposed algorithm is stable for the native behavior of the half-wavelength line, including the resonance zones and their mitigation procedures. In addition, the algorithm is immune to the fault insertion angle, fault resistance, and line loading level. Finally, the algorithm could be applied in commercial microprocessor-based relays or could be used as a post-fault analysis tool.

In this study, the main results of a new mitigation method to single-phase auto-reclosing switching in half-wavelength transmission lines are presented. Initially, the behaviour of single-phase reclosing on conventional lines was evaluated, then, the results obtained for half-wavelength lines are presented. Finally, the proposed solution for the manoeuvre to be successfully executed is described. The study proposes a very advantageous solution for the application of the single-phase switching in half-wavelength lines.

This paper presents an adaptive single-phase auto-reclosing method based on harmonic voltage measurement through a digital harmonic filter. This filter and the transmission system were modelled in a real-time digital simulator (RTDS). A distance relay was used for protection and reclosing, responding as if it was in field operation. The studied system was based on an actual 500 kV Brazilian system. This work highlights the advantage of using the adaptive technique when compared with regular fixed dead-time procedure.

This paper presents a comparison of secondary electric arcs behavior for reclosing applications. The main objective of the paper is to show the differences in secondary arcs during simulations, laboratory tests and real life events. These comparisons can help engineers develop adaptive reclosing algorithms and improve power system stability. A software arc model, a laboratory test result and field events' harmonic contents were analyzed. Although the harmonics may differ in each method, they all provide enough information to be used in the reclosing algorithms.

This study presents the results of single-phase auto reclosing technique tests, comparing the performance of traditional procedure and fast adaptive procedure. The last is based on the measurement of voltage harmonic content on the transmission line faulty phase terminals. The transmission system used was modelled on the real-time digital simulator with a distance relay and a quality meter to more realistically implement the reclosing techniques. The studied system was based on an actual Brazilian 500 kV transmission system. This study highlights the advantages of using the adaptive technique opposite to the use of traditional manoeuvre.

This work proposes the use of a novel faulted phase-selection phasor-based algorithm to solve the high-resistance and weak-infeed fault condition selection problem in existent long compensated transmission lines. The algorithm was originally developed for future half-wavelength lines (3000 km for 50 Hz system or 2500 km for 60 Hz), and was slightly modified and tested in a real 645 km 1000 kV Ultra High Voltage transmission system. The algorithm was implemented in a programmable protective relay and tested using a real-time simulator. A series of tests under extreme conditions (such as high impedance fault and very week infeed system together) were conducted to evaluate the performance and robustness of the proposed algorithm.

Vista toda a importância dos sistemas elétricos de potência, faz-se necessária a utilização dos sistemas de proteção em conjunto. Por sua vez, é ideal que, após os relés de proteção serem parametrizados, estes sejam ensaiados para garantir sua correta atuação. Uma alternativa para isso é a simulação do sistema elétrico em questão através do ATP em conjunto com os relés implementados na linguagem MODELS. Dessa maneira, utilizando-se desses métodos, neste trabalho modelou-se um sistema elétrico real em conjunto com sua proteção diferencial de barras.

A pesquisa proposta no projeto de Iniciação científica, realizada no Laboratório de Estudos de Transitórios Eletromagnéticos e de Proteção em Sistema de Potência (LTRANSP) teve o enfoque no estudo do comportamento da proteção diferencial de transformador utilizada em um sistema elétrico de potência. A proposta foi reproduzir os problemas encontrados em campo, tanto de saturação dos equipamentos de medição, quanto de manobras e defeitos que acarretam na operação indevida dos relés de proteção.

In this work we propose a new mitigation method to minimize secondary arc current and analyze the behavior of electrical quantities related to the single-phase auto reclosing in half-wavelength (HWL) transmission lines. Initially, such quantities are presented for a half-wavelength line without any device that minimizes the secondary arc current. Following, an innovative new secondary arc current mitigation procedure is presented and implemented. The mitigation method proposed in this work is implemented through the insertion of a circuit-breaker in both transformers neutrals at the transmission line terminals, with the intention of isolating the transformers during fault secondary. Our results show that the behavior of electrical quantities related to the single-phase reclosing switching in such very long line is very different when compared with conventional lines. Their values get close to conventional lines when the proposed mitigation technique is implemented. Furthermore, with the proposed solution the secondary arc has a high probability of self-extinguishing during regular dead-time, allowing the application of the single-phase auto-reclosing switching in HWL. The simulations were implemented in a real time digital simulator.