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2 2018

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Distance protection analysis applied for distribution system with distributed generation

Campos J., Sanca H. S., Costa F. B., Souza B. A.

Przegląd Elektrotechniczny

2018

R. 94, nr 3

13--17

In power systems, the over-current protection scheme and, optionally with directional function, and distance function are the main protection used, principally, where the power flow is on both sides as in distribution system with distributed generation (DG), for example. However, with the increasing of DG penetration in the distribution system, these protections can not be secure and impacts in the coordination of the protection are caused due to the power flow is on both sides. Therefore, new types of protection as distance protection are candidates to solve the coordination problem in the distribution system with DG. In this paper, is proposed an application of the distance protection in the distribution system with DG, and several cases of faults and the impacts on the distance protection are evaluated in presence of DG. In the simulation and analysis of faults were varied the fault inception angle, fault type, fault resistance, and fault location. The correct and bad trips are analyzed to evaluate the distance relay performance. The distance relay used in the distribution system with DG had good performance in all simulation cases. Besides, the better performance of the distance protection proves which may be used in distribution systems with DG.

W systemach energetycznych zabezpieczenie przed przeciążeniem prądowym (opcjonalnie wraz z funkcją kierunku i odległości) jest główną metoda zabezpieczenia, szczególnie gdy moc może być przekazywana w dwóch kierunkach. W artykule zaproponowano nowy typ zabezpieczenia uwzględniający funkcje odległości. Uwzględniono też możliwość wykrywania błędów i możliwość określania ich położenia.

Assessment of power frequency estimation methods in distributed generation in islanding condition

Sanca H. S., Campos J. T. L. S., Souza F. C., Costa F. B., Souza B. A.

Przegląd Elektrotechniczny

2018

R. 94, nr 5

1--6

In this paper, a method for evaluation of power frequency estimation during transient operation in distributed generation (DG) in islanding conditions is presented. For this end, five methods of fundamental frequency estimation are evaluated in a distribution system with distributed generation in islanding operation, such as: (a) zero crossing, (b) adjustment of points to a pure sinusoidal waveform, (c) hybrid method, (d) discrete Fourier transform method based, and (e) Prony-Fourier-based algorithm. The estimators are compared and evaluated in two different ways, using two analytical functions, and in an electric power distributed system with DG in islanding condition. The evaluation methodology for the frequency estimators are based in statistical errors, taking into account mean, mean square error. The zero-crossing and discrete Fourier transform based estimator presented better results in comparison with the other evaluated algorithms. However, the discrete Fourier transform presented good results in the estimated frequency in the three evaluated cases.

W artykule oceniono metody badania częstotliwości w stanach przejściowych rozproszonych sieci energetycznych w warunkach tworzenia się wysp. Zbadano pięć metod: zero crossing, APPSW, hybrydową, DFT iProny. Najlepszy wyniki osiągnięto przy stosowaniu metody zero-crossing (Przeciecia osi zero) I DFT.