Document Type : Research Paper
Authors
1
Electrical and computer Eng. faculty, Babol Noshirvani University of Technology, Babol, Iran.
2
Electrical and computer Eng. faculty, Babol Noshirvani University of Technology, Babol, Iran
3
Power system department, Electrical and Computer Eng. faculty, Babol Noshirvani University of Technology, Babol, Iran.
4
Faculty of Electrical and computer Eng., Mazandaran University of Science and Technology, Behshahr, Iran
Abstract
Following occurrence of transient single-phase fault on transmission line, a primary arc is typically initiated. For fault clearing, the protection system temporarily disconnects the affected phase. After this operation, the primary arc is extinguished; but, due to the electric field surrounding the healthy phases and capacitance between the conductors, a large voltage is induced on the opened phase. So, due to the weakness of the insulation properties at the fault location, this voltage can lead to a reestablishing the arc at fault location, known as secondary arc. A secondary arc continues until the insulation properties of the air around the fault return to normal, so the reclosing operation will fail if it is reconnected prior to the secondary arc being extinguished. Therefore, in recent years, some studies have been conducted on identifying the secondary arc extinction time and the proper procedure for reclosing. This article aims to evaluate the insulation conditions at the fault location after the secondary arc has been extinguished to determine the appropriate time for reclosing. For this purpose, it is necessary to estimate the maximum voltage at the moment of closing immediately following the extinction of the secondary arc. Following this, the reignition voltage at the fault location is continuously calculated and by comparing its magnitude with the maximum voltage estimated from the moment of closing, a reclosing command is issued. In order to conduct this study, a 400kV line is simulated under different fault conditions and the proposed method is implemented, analyzed, verified, and evaluated.
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