Milad Doostan - Academia.edu (original) (raw)

Papers by Milad Doostan

In order to study the problems posed by lightning stroke on vastly exposed transmission lines, it... more In order to study the problems posed by lightning stroke on vastly exposed transmission lines, it is essential to study different lightning overvoltage phenomena. One of the most significant electrical transients caused by lightning is backflashover. In this paper, by applying Monte Carlo method and considering accurate models of transmission line, grounding system and physical model of breakdown in insulator gap, the backflashover is studied on a 230 kV double circuit transmission line. To apply the proposed approach, the selected case study is simulated in EMTP-RV software and the results are presented.

Line arresters are considered as an effective way to improve the lightning performance of transmi... more Line arresters are considered as an effective way to improve the lightning performance of transmission lines, especially in parts of line that suffer from high soil resistivity and lightning ground flash density. This paper presents results of the application of line surge arresters on the 132KV double circuit transmission line in EMTP-RV and all the practical scenarios for installation of surge arresters. The study has shown that a significant level of improvement can be reached by installing arresters at all or only some of the line phases. It can increase the strength of the line to withstand lightning currents up to -292kA. the probability of having this lightning current, is practically zero.

This paper presents a study on naturally aged timing relays. This study employs thermally acceler... more This paper presents a study on naturally aged timing relays. This study employs thermally accelerated aging method. This method includes various inspection, surveillance and monitoring (ISM) tests to identify and characterize the process of material and component degradation during the service which leads to the estimation of service life for the target relays. After applying the aforementioned tests, several observations are made and the results are provided. Also, some recommendations are made at the end to improve the thermally accelerated aging analysis in the future.

This paper examines the outage rate caused by lightning strokes on compact transmission lines (TL... more This paper examines the outage rate caused by
lightning strokes on compact transmission lines (TL). Compact
and conventional transmission lines are different in terms of
design and structure. Due to such differences, the previous
lightning performance studies on conventional TL are useless in
understanding the lightning performance of compact TL; hence,
such studies have to be updated. In this paper, the
aforementioned differences have been taken into the
consideration. The lightning performance of compact TL has
been studied by application of Monte Carlo method. Moment
method is used to determine tower surge impedance by
SuperNEC software and an approximate model has been
introduced for tower modeling in EMTP-RV. After the accurate
modeling of all components, backflashover analysis has been
performed and at the end, the number of outages in the
simulated sample size has been presented.