Power systems
Hassan Abniki; Mostafa Hajati Samsi; Behrooz Taheri; Seyed Amir Hosseini
Abstract
Power transmission lines are vital components of today's power systems. These power lines transmit the electricity produced in power plants in high volume and with very low losses to distant areas so that it can be reached to consumer through distribution networks. In fact, these lines are the intermediary ...
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Power transmission lines are vital components of today's power systems. These power lines transmit the electricity produced in power plants in high volume and with very low losses to distant areas so that it can be reached to consumer through distribution networks. In fact, these lines are the intermediary between major energy producers and distribution networks. Accordingly, these transmission lines are of a great importance and must be protected appropriately with a suitable protection system. Distance relays are widely used to protect these lines due to their convenient coordination characteristics and simplicity. High impedance fault (HIF) can be a critical challenge for distance relays due to their low current amplitude and similarity to conventional events in power systems such as capacitive bank switching. For this reason, in this paper a new approach is presented based on the instantaneous frequency variations obtained from the current RMS in order to detect the high impedance fault. This method detects high impedance faults via calculating a Detection index (DI) and considering a threshold value. The proposed method has been tested using DIgSILENT and MATLAB software in an IEEE standard 39-bus network. The presented results evidently demonstrate that the proposed method is suitable for detecting HIF and Low impedance fault (LIF). In addition, this method has a proper performance during capacitor bank switching and can well distinguish between HIF and capacitive bank switching. Moreover, the presented method is resistant to noise and also is capable to detect the faulty phase.
Power systems
Sirus Salehimehr; Behrooz Taheri; Seyed Amir Hosseini; Hossein Askarian Abyaneh; Farzad Razavi
Abstract
In this paper, a new method based on Hilbert transform is proposed to detect the power swing and faults occurring during the power swing. The proposed method operates independently from the system parameters. As well as, this method has the ability to detect different types of power swings, including ...
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In this paper, a new method based on Hilbert transform is proposed to detect the power swing and faults occurring during the power swing. The proposed method operates independently from the system parameters. As well as, this method has the ability to detect different types of power swings, including stable, unstable, and multi-mode power swings, and also can differentiate the power swing from the faults for blocking or unblocking the distance relay. In order to evaluate the proposed method, various types of power swing and simultaneous faults are simulated in DIgSILENT software and then using the obtained matrix data from the current signals, the proposed algorithm has been implemented in Matlab software using the Hilbert transform. The results of this study show that the proposed method can detect different types of power swing successfully. In addition, it has been shown that the proposed method operates very fast; besides when a fault occurs simultaneously with the power swing unblocks the relay as soon as possible. This method has been also implemented practically on a distance relay and is tested by a relay tester device made by Vebko Amirkabir knowledge-based company. The results obviously show that the proposed method has a better operation than industrial conventional methods.