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Author

Mahdi Davarpanah

Bio: Mahdi Davarpanah is an academic researcher from University of Tehran. The author has contributed to research in topics: Electric power system & Permanent magnet synchronous generator. The author has an hindex of 19, co-authored 48 publications receiving 720 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, a least error squares (LES) filter is used to estimate the phasor parameters of the CT secondary current and a new minimum estimation error tracking approach is proposed to enhance the precision of the estimation.
Abstract: A current transformer (CT) is accurately modeled for representation of the CT saturation effects on digital protective relays. Simulation studies performed in the PSCAD/EMTDC platform are used to investigate the impacts of CT saturation on the current phasor estimation. A new algorithm is also proposed for detection and compensation of CT saturation effects, based on: a least error squares (LES) filter which estimates the phasor parameters of the CT secondary current; a novel saturation detection method which uses the output of the LES filter for saturation detection; and a new minimum estimation error tracking approach which enhances the precision of the phasor estimation. The proposed saturation detection/compensation algorithm is independent of the parameters of the CT, the burden, and the power system. The study results show that the proposed algorithm: 1) reconstructs the distorted current waveform, under dc and ac saturation conditions, with the required precision and speed and 2) performs satisfactorily under inductive burden and under deep and slight saturation conditions.

75 citations

Journal ArticleDOI
TL;DR: In this paper, a new approach for the loss-of-excitation (LOE) relay is presented, which exploits a combined scheme based on the derivative of the terminal voltage and the output reactive power of the generator.
Abstract: The loss-of-excitation (LOE) event threatens the generator and power system stability. Several methods have been proposed for LOE detection, most of which are based on the impedance trajectory. These approaches may not be able to distinguish between LOE and the stable generator swing (SGS). Thus, allocating an operation time delay is usually used to overcome the LOE relay misoperation due to SGS. This paper presents a new approach for the LOE relay. The proposed strategy exploits a combined scheme based on the derivative of the terminal voltage and the output reactive power of the generator. Comprehensive simulation studies are accomplished for various generator conditions and system disturbances to determine the relay setting and to evaluate its performance. The performed studies demonstrate that the proposed strategy enhances security and operation time of the LOE relay, compared with some existing methods.

61 citations

Journal ArticleDOI
TL;DR: 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.
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.

53 citations

Journal ArticleDOI
TL;DR: In this paper, a new approach to detect loss of excitation (LOE) based on calculating the synchronous generator internal voltage is presented, which can be used as a straightforward index to discriminate LOE events from system disturbances more quickly and robustly than the conventional indices.
Abstract: The excitation system of a synchronous generator has a major role in proper operation and control of the generator. Loss of excitation (LOE) may cause harmful effects on the both generator and power system. This paper presents a new approach to detect LOE based on calculating the synchronous generator internal voltage. This parameter is considerably sensitive to LOE and can be used as a straightforward index to discriminate LOE events from system disturbances more quickly and robustly than the conventional indices. A novel and practical technique with minimum computational burden is presented to calculate the generator internal voltage. To evaluate the proposed algorithm, LOE events in a multimachine test system are investigated. In addition, the proposed approach is experimentally evaluated on a 10 kVA synchronous generator. Performed studies demonstrate that the proposed strategy not only noticeably decreases the LOE relay operation time, but also desensitizes its maloperation to system disturbances.

45 citations

Journal ArticleDOI
TL;DR: Detailed mathematical formulation for the proposed OOS detection method is provided and the results confirm that the proposed approach can accurately identify OOS conditions, earlier than the rotor angle noticeably increases.
Abstract: This paper introduces a new approach, based on faster-than-real-time (FTRT) analysis, to predict out-of-step (OOS) condition of a turbine-generator (T-G) unit subsequent to a fault scenario. The proposed FTRT analysis is based on 1) solving a state-space model of the T-G electromechanical system and corresponding controllers without the need for online measurements, and 2) an estimated Thevenin equivalent of the rest of the power system. The measurement-free FTRT analysis is carried out after the Thevenin parameters are estimated subsequent to the fault clearance instant. Equal area criterion is applied on the predicated variables to detect OOS condition. A reliable decision can be made based on this approach, since it does not involve simplifying assumptions contrary to the existing approaches. The FTRT approach accurately considers the impacts of the detailed model of the generator, automatic voltage regulator, prime mover, governor system, and the host power system. This paper provides detailed mathematical formulation for the proposed OOS detection method and verifies its feasibility and accuracy based on single machine and large test systems. The proposed approach is also implemented on an industrial platform and evaluated. The results confirm that the proposed approach can accurately identify OOS conditions, earlier than the rotor angle noticeably increases.

40 citations


Cited by
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Book ChapterDOI
11 Dec 2012

1,704 citations

Journal ArticleDOI
TL;DR: The results demonstrate that the adoption of demand response programs can reduce total operation costs of a microgrid and determine a more efficient use of energy resources.

249 citations

Journal ArticleDOI
TL;DR: This bibliography will aid academic researchers and practicing engineers in adopting appropriate topics and will stimulate utilities toward development and implementation of software packages.
Abstract: Phasor measurement units (PMUs) are rapidly being deployed in electric power networks across the globe. Wide-area measurement system (WAMS), which builds upon PMUs and fast communication links, is consequently emerging as an advanced monitoring and control infrastructure. Rapid adaptation of such devices and technologies has led the researchers to investigate multitude of challenges and pursue opportunities in synchrophasor measurement technology, PMU structural design, PMU placement, miscellaneous applications of PMU from local perspectives, and various WAMS functionalities from the system perspective. Relevant research articles appeared in the IEEE and IET publications from 1983 through 2014 are rigorously surveyed in this paper to represent a panorama of research progress lines. This bibliography will aid academic researchers and practicing engineers in adopting appropriate topics and will stimulate utilities toward development and implementation of software packages.

239 citations

Journal ArticleDOI
TL;DR: The proposed control design permits better DC microgrid integration and provides possibility to reduce the negative impact on the utility grid thanks to the supervision interface, and the power balancing control interface provides possibility for advanced energy management with low speed communication.
Abstract: Aiming at photovoltaic (PV)-storage urban building integrated system, this paper proposes a DC microgrid with multi-layer control and smart grid communications. The paper focuses on power balancing, with load shedding and PV constrained production, and takes into account the grid availability and grid vulnerability by smart grid messages. The system behavior modeling by MATLAB Stateflow leads to the whole control strategy design, which concerns the power balancing and imposed power limits by the utility grid, while providing interface for energy management. Experimental results evaluate the feasibility of the proposed control strategy. As further development of this control design, an intelligent multi-layer supervision is suggested. This supervision, able to exchange data with the smart grid, deals with the end-user demand, forecast of photovoltaic production, prediction of load consumption, and energy management. The major technical contribution of this paper is linked to the proposed control design that permits better DC microgrid integration (avoids undesired injection, mitigates fluctuations in grid power, reduces grid peak consumption) and provides possibility to reduce the negative impact on the utility grid thanks to the supervision interface. The power balancing control interface provides possibility for advanced energy management with low speed communication.

221 citations

Journal ArticleDOI
TL;DR: A new communication-based protection scheme for isolated microgrids where a data mining approach is used to identify the relay settings and parameters and a feature selection technique is implemented to help identify the most relevant electrical features required for the fault detection and the best communication strategy to use between relays.
Abstract: The protection of a microgrid containing inverter- based distributed generators (IBDGs) presents several problems if traditional techniques which rely on the current (fuses and overcurrent relays) are used. A possible solution to these problems is the use of a new type of the relay which takes advantage of the enhanced processing techniques and communication infrastructure, both of which are recently becoming available for power networks application. This paper proposes a new communication-based protection scheme for isolated microgrids where a data mining approach is used to identify the relay settings and parameters. A feature selection technique is implemented to help identify the most relevant electrical features required for the fault detection and to establish the best communication strategy to use between relays. The proposed approach is tested using a MATLAB simulation of a facility scale isolated microgrid embedded with IBDGs. The results show that a differential protection scheme that relies on symmetrical components is the most effective strategy for protecting microgrids with IBDGs.

194 citations