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Transmission Line Pilot Relaying
Published in Walter A. Elmore, Pilot Protective Relaying, 2018
Current transformer deficiencies, in general, cause distance relays to see a lower effective current than they would see otherwise. This causes them to reach a shorter distance than they would if there were no ct saturation. Relays set to reach all faults on a protected transmission line will, in response to this effect, not fail to operate, but rather, will sense that the fault is farther away than it actually is. This will cause an electromechanical pilot distance scheme with minor ct saturation to trip perhaps as much as 10-20 ms slower because of its dependency on energy level at the relay. A numerical relay encountering the same conditions will experience the same “reach-shortening” effect, but will not be subject to the operating time variations.
Transformer Protection
Published in Ramesh Bansal, Power System Protection in Smart Grid Environment, 2019
A power transformer nameplate reads: 20 MVA, 33/11 kV, Dyn1. Biased differential protection is to be applied to this transformer. A numerical relay is available for the implementation. Suggest and provide the required solution, including the relay settings. Assume the following information:Transformer has load tap changing of 10%.CT error of 5%.The relay has current setting range from 0.2 to 1.2A in steps of 0.01A.
Artificial Intelligence Application for HVDC Protection
Published in Almoataz Y. Abdelaziz, Shady Hossam Eldeen Abdel Aleem, Anamika Yadav, Artificial Intelligence Applications in Electrical Transmission and Distribution Systems Protection, 2021
Zahra Moravej, Amir Imani, Mohammad Pazoki
Since the main purpose of power system protection is to keep the power system stable by isolating the faulty section of line, fault identification in the minimum time is necessary. Emergence of smart numerical relay in the 1980s led to the introduction of AI and pattern recognition application to power system protection. The most important application of AI in protection is fault identification containing fault detection, classification, and location. The fault identification process contains three basic stages, shown in Figure 16.1.
Investigation of distance relay settings under normal and stressed conditions in a wind farm environment
Published in International Journal of Ambient Energy, 2023
Priya R. Pattanaik, Basanta K. Panigrahi, Subhendu Pati, Smaran K. Sanyal
Modern numerical relays have industry standard multiple setting group features which make the protection function adaptive in nature (Sachdev and Ratan 2009). The programmable scheme logic (PSL) in numerical relay allows flexible settings which can change according to system conditions. In this paper, mainly a study has been carried out that strongly suggests having an adaptive PSL algorithm for a numerical distance relay in a wind farm environment.