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In this paper a methodology to select the best protection scheme for TOFFs is presented. The proposed algorithm will help a protection engineer to decrease the computational burden needed to select the best protection scheme for any TOFF. The procedure is applied to a real case study (one of the TOFFs of Iran's power grid) and the results are shown and discussed.
Because of the larger trigger lighting area, 220 kV double circuit transmission line is more vulnerable by lightning, and shielding failure and back flashover are more prominent. Therefore, the accurate assessment of the lightning protection performance of 220 kV double circuit transmission line is crucial to ensure the security and stability of the transmission network. This paper presents the main...
Field study indicates that more than 90% lightning stroke trip-out accidents for UHV transmission lines are caused by lightning shielding failure flashover. The large scale of the tower and the high operation AC voltage increase the probability of direct lightning strokes attaching to the phase conductor of double circuit UHV transmission line. The unexpected high lightning shielding failure flashover...
This paper introduces the method of setting up of the 750kV line model, in accordance with the model of 750kV lines running in different systems under various fault happened a detailed simulation, and according to the simulation results discussed in the transient process of 750kV line and the impact of the protection algorithm of the transient course is discussed.
A useful tool for the evaluation of the lightning performance of overhead transmission lines has been developed in Matlab. The software (LPTL) runs as a Microsoft Windows application and features a user-friendly graphics interface. For given overhead transmission line parameters, ground flash density and lightning crest current distribution the lightning performance of the line can be easily evaluated...
The purpose of this study is to develop a method to measure transmission line parameters for protection relay setting. For relaying schemes such as distance relays, current differential relays and fault locators, it is very useful to ascertain the precise setting values in service, without the need for setting calculations prior to installation, and also for the relays to be able to adaptively change...
This paper discusses the theory of the neutral reactors compensation of shunt reactor on UHV (ultra high voltage) double-circle lines and offers the calculation formulas of 4 connection types of neutral reactor compensation schemes. Using Huainan-Shanghai UHV double-circle line as an example, the value range of neutral reactor for existing compensation scheme in this project was obtained. According...
Single phase switching has become an increasingly more viable approach to the operation of EHV systems in recent years. Indeed, single phase reclosing, if successful, represents a significant step in improving system performance and is an attractive, economical means of obtaining acceptable transient stability with fewer lines. Single phase reclosing has the additional benefits of reducing switching...
The main purpose of this work is to present a performance analysis of numerical distance protection applied in high voltage transmission lines, more specifically in the 500 kV transmission lines of CEMIG (Energy Company of Minas Gerais - Brazilian Energy Utility) between the Vespasiano 2 - Neves 1 (short line - 23.9 km) and Vespasiano 2 - Mesquita (long line - 148.6 km) substation. The need for energy...
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