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Showing 2 results for Out-of-Step Protection
Impedance-Based Out-of-Step Protection of Generator in the Presence of STATCOM
S. R. Hosseini, M. Karrari, H. Askarian Abyaneh,
Volume 15, Issue 4 (12-2019)
Abstract
This paper presents a novel impedance-based approach for out-of-step (OOS) protection of a synchronous generator. The most popular and commonly used approaches for detecting OOS conditions are based on the measurement of positive sequence impedance at relay location. However, FACTS devices change the measured impedance value and thus disrupt the performance of impedance-based relay function. In this paper, the performance of synchronous generator OOS protection function connected to the transmission line in the presence of a static synchronous compensator (STATCOM) is investigated. Moreover, an analytical adaptive approach is used to eliminate the effect of STATCOM. This approach requires only the remote bus voltage and current phasors to be sent to the relay location via a communication channel. Simulation results show that STATCOM changes impedance trajectory and causes the incorrect operation of OOS relay. Furthermore, the proposed approach corrects the relay mal-operation and improves the accuracy of OOS impedance-based function when the STATCOM is used in the system.​

Modified Impedance-Based OOS Protection Based on On-Line Thévenin Equivalent Estimation
S. R. Hosseini, M. Karrari, H. Askarian Abyaneh,
Volume 17, Issue 1 (3-2021)
Abstract
In this paper, a novel approach based on the Thévenin tracing is presented to modified conventional impedance-based out-of-step (OOS) protection. In conventional approach, the OOS detection is done by measuring positive sequence impedance. However, the measured impedance may be change due to different factors such as capacitor bank switching and reactive power compensators that it can cause the relay to malfunction. In this paper, first, an on-line Thévenin equivalent (TE) approach based on the recursive least square (RLS) is presented. Then, a protection function is developed based on online network Thévenin equivalent parameters to correct the measured impedance path. The main feature of this method is the use of local voltage and current measurements for Thévenin equivalent estimation and OOS protection. The performance of the proposed method is investigated by simulation of synchronous generator OOS protection function in the presence of a static synchronous compensator (STATCOM). The simulation results show that, STATCOM changes the impedance path and can cause the incorrect diagnosis of OOS relay. Furthermore, the proposed method corrects the impedance path and improves the accuracy of OOS impedance-based function when the STATCOM is installed in system.

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© 2022 by the authors. Licensee IUST, Tehran, Iran. This is an open access journal distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) license.