Search

Your search keyword '"Davarpanah, Mahdi"' showing total 146 results
Start Over Author "Davarpanah, Mahdi"
146 results on '"Davarpanah, Mahdi"'

3. Internal faults in stator winding of synchronous generator: Modelling, detecting and protecting.

Author

Rezaei, Amir Hossein, Beikbabaei, Milad, Abedini, Moein, and Davarpanah, Mahdi

Subjects
GEOLOGIC faults, SIMULATION software, STATORS, MAGNETIC fields, SECURITY systems, SYNCHRONOUS generators
Abstract

Protection of synchronous generators (SGs) against internal faults, such as stator earth fault (SEF) and turn‐to‐turn fault (TTF), is crucial for ensuring the stability and security of the power system. This paper presents a phase domain model for simulating SEF and TTF in SGs, requiring only nameplate data and avoiding the need for complex geometric data or lengthy simulations typical of FEM models. The stator winding is divided into three sections, allowing for the calculation of magnetic field distribution in both healthy and faulty conditions. The model is capable of simulating short‐circuit turns at various locations within the stator winding with high accuracy and speed. The dynamic response of the generator is also incorporated into the model. The model's accuracy is validated through comparison with results from multiphysics simulation software. Furthermore, this study addresses the limitations of conventional protection methods in detecting TTF and proposes a novel, simple, fast, and accurate protection logic that can be implemented in digital protection relays and is effective across a wide range of TTF scenarios. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

20. An effective controlled islanding method for power grid through a sequence of optimization problems

Author

Amini, Mahdi, Samet, Haidar, Seifi, Ali Reza, Davarpanah, Mahdi, Amini, Mahdi, Samet, Haidar, Seifi, Ali Reza, and Davarpanah, Mahdi

Abstract

Controlled islanding is an important approach to prevent instability in power grids. In this paper, a novel approach is proposed for power system separation, which consists of two steps: 1) Finding multiple islanding scenarios, 2) Choosing the best option to reach the most desirable island. In the first step, different islanding solutions are determined by a proposed hierarchical clustering method. In this algorithm, which is based on minimum active power flow disruption objective function, the generator coherency constraints are considered in the clustering process. In the second step, the best separation scenario can be chosen based on an arbitrary objective function. Particularly, in this paper, the amount of load shedding and the voltage profile deviation after separation are considered as the final criteria to select the best solution among available options. In so doing, the degree of load importance is also taken into account. The proposed two-step method is applied on the IEEE 9-bus test system and also it is evaluated on the IEEE 39-bus grid. The simulation results on the IEEE 39-bus grid and the comparative analysis with a state-of-the-art method confirm that the final islanding solution is more optimized based on the secondary criteria, which cannot be concerned in the existing approaches. Moreover, the proposed method is computationally efficient and can be employed in the real-scale power grids.

Published
2022

22. Determining optimal neutral reactor to limit overvoltages and duration of secondary arc of transmission lines.

Author

Mohammadi, Abolfazl, Abedini, Moein, and Davarpanah, Mahdi

Subjects
ELECTRIC lines, OVERVOLTAGE, SHUNT electric reactors, ELECTRIC transients, POWER system simulation, FAULT currents
Abstract

Even though shunt compensation of transmission lines (TLs) is a common practice to limit the overvoltages stemming from the Ferranti effect, it may cause transient and steady‐state resonant overvoltages when one phase is left open due to the single‐pole‐open condition following the temporary phase‐to‐ground (Ph‐g) fault. Furthermore, the existing shunt reactors potentially increase the duration of the secondary arc current at the fault point and hence prevent offering fast single‐pole reclosing. To exploit the mentioned issues, in recent studies, a neutral reactor is introduced, which is installed in the neutral point of the shunt reactors; nonetheless, obtaining the appropriate amount of it is remarkably challenging. In this paper, an optimal neutral reactor (ONR) is determined based on an optimization problem, which minimizes the neutral reactor cost subject to limiting both resonant overvoltages and the duration of the secondary arc current. In modelling, the Laplace domain is employed rather than the phasor domain to consider both transient and steady‐state conditions since this technique allows having better control over transient overvoltages as well as transient secondary arc. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

25. Fast and reliable CT saturation detection using a combined method

Author

Dashti, Hamed, Pasand, Majid Sanaye, and Davarpanah, Mahdi

Subjects
Electric transformers -- Design and construction, Electric fault location -- Methods, Electric power transmission -- Research, Algorithms -- Usage, Algorithm, Business, Computers, Electronics, Electronics and electrical industries
Abstract

Busbar differential relays may operate incorrectly for external faults due to current-transformer (CT) saturation. In this paper, two different techniques are suggested to detect CT saturation. The first proposed technique is based on the fact that the waveshape of the CT secondary current changes significantly at the instant of the saturation. Based on this feature, an algorithm which uses the second derivative of CT output current is developed. It uses an adaptive threshold to detect CT saturation fast. The second proposed technique utilizes two criteria based on the zero crossing principle. Utilizing the combination of the second derivative and zero crossing techniques results in a powerful and reliable scheme which is able to detect various CT saturation cases correctly and quite fast. The proposed method is able to detect even small CT saturation events. A real 400-kV busbar is simulated using PSCAD/EMTDC for evaluating the performance of the proposed algorithm. The obtained results demonstrate precise operation of the proposed algorithm in different conditions. Index Terms--Busbar differential protection, current-transformer (CT) saturation detection, second derivative, zero crossing.

Published
2009

Catalog

Books, media, physical & digital resources
See catalog results