Understanding power transformer frequency response analysis signatures
- Authors: Abu-Siada, Ahmed , Hashemnia, Naser , Islam, Syed , Masoum, Mohammad
- Date: 2013
- Type: Text , Journal article
- Relation: IEEE Electrical Insulation Magazine Vol. 29, no. 3 (2013), p. 48-56
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- Description: This paper presents a comprehensive analysis of the effects of various faults on the FRA signatures of a transformer simulated by a high-frequency model. The faults were simulated through changes in the values of some of the electrical components in the model. It was found that radial displacement of a winding alters the FRA signature over the entire frequency range (10 Hz-1 MHz), whereas changes due to axial displacement occur only at frequencies above 200 kHz. A Table listing various transformer faults and the associated changes in the FRA signature was compiled and could be used in the formulation of standard codes for power transformer FRA signature interpretation.
Improving voltage of remote connection using wind-solar farms equipped with new voltage control strategy based on virtual impedance monitoring enabled by IEC 61850 communication
- Authors: Aghanoori, Navid , Masoum, Mohammad , Islam, Syed , Abu-Siada, Ahmed , Nethery, Steven
- Date: 2019
- Type: Text , Journal article
- Relation: IET Generation, Transmission and Distribution Vol. 13, no. 11 (2019), p. 2112-2122
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- Description: This study explores how the voltage control of a remote part of the utility gird can be improved using more sophisticated voltage control on wind-solar farms equipped with fast communication platforms. The idea is to make renewable plant the master voltage controller during large disturbance events in the grid. This is done by proposing an enhanced voltage droop control strategy based on instantaneous reactive power consumption by monitoring the virtual impedance of the point of connection using a new customised data class model of IEC 61850 communication protocol. The conventional centralised voltage droop control strategy and the proposed instantaneous direct voltage control method are both implemented on the White Rock Solar Wind Farm in NSW, Australia and their performances are compared using both MATLAB Simulink simulations under 5% voltage step disturbances, single-phase-to-ground and three-phase-to-ground faults as well as some tests conducted in the field.
Enhancement of microgrid operation by considering the cascaded impact of communication delay on system stability and power management
- Authors: Aghanoori, Navid , Masoum, Mohammad , Abu-Siada, Ahmed , Islam, Syed
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal of Electrical Power and Energy Systems Vol. 120, no. (2020), p.
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- Description: Power management, system stability and communication structure are three key aspects of microgrids (MGs) that have been explored in many research studies. However, the cascaded effect of communication structure on system stability followed by the impact of stability on the power management has not been fully explored in the literature yet and needs more attention. This paper not only explores this cascaded impact, but also provides a comprehensive platform to optimally consider three layers of MG design and operation from this perspective. For generation cost minimization and stability assessment, the proposed platform uses an adaptive particle swarm optimization (PSO) while a new class of data exchange scheme based on IEC 61850 protocol is proposed to reduce the communication time delays among the inverters of distributed generations and the MG control center. This paper also considers the system stability using small-signal model of a MG in a real-time manner as an embedded function in the PSO. In this context investigations have been conducted by modeling an isolated MG with solar farm, fuel cell generator and micro-turbine in MATLAB Simulink. Detailed simulation results indicate the proposed power and stability management method effectively reduces the MG generation cost through maximizing the utilization of the available renewable generations while considering system stability. © 2020 Elsevier Ltd
Real-time charging coordination of plug-in electric vehicles based on hybrid fuzzy discrete particle swarm optimization
- Authors: Hajforoosh, Somayeh , Masoum, Mohammad , Islam, Syed
- Date: 2015
- Type: Text , Journal article
- Relation: Electric Power Systems Research Vol. 128, no. (2015), p. 19-29
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- Description: The main impact of uncoordinated plug-in electric vehicle (PEV) charging is adding new time-variant loads that can increase the strains on the generation units, transmission and distribution systems that may result in unacceptable voltage drops and poor power quality. This paper proposes two dynamic online approaches for coordination of PEV charging based on fuzzy genetic algorithm (FGA) and fuzzy discrete particle swarm optimization (FDPSO). The algorithms will minimize the costs associated with energy generation and grid losses while also maximizing the delivered power to PEVs considering distribution transformer loading, voltage regulation limits, initial and final battery state of charges (SOCs) based on consumers' preferences. The second algorithm relies on the quality and speed of DPSO solution for more accurate and faster online coordination of PEVs while also exploiting fuzzy reasoning for shifting charging demands to off-peak hours for a further reduction in overall cost and transformer loading. Simulation results for uncoordinated, DPSO, FGA and FDPSO coordinated charging are presented and compared for a 449-node network populated with PEVs. Results are also compared with the previously published PEV coordinated charging based on maximum sensitivity selections (MSS). Main contributions are formulating the PEVs charging coordination problem and applying different optimization methods including online FGA and FDPSO considering different driving patterns, battery sizes and charging rates, as well as initial SOCs and requested final SOCs. © 2015 Elsevier B.V.
Online optimal variable charge-rate coordination of plug-in electric vehicles to maximize customer satisfaction and improve grid performance
- Authors: Hajforoosh, Somayeh , Masoum, Mohammad , Islam, Syed
- Date: 2016
- Type: Text , Journal article
- Relation: Electric Power Systems Research Vol. 141, no. (2016), p. 407-420
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- Description: Participation of plug-in electric vehicles (PEVs) is expected to grow in emerging smart grids. A strategy to overcome potential grid overloading caused by large penetrations of PEVs is to optimize their battery charge-rates to fully explore grid capacity and maximize the customer satisfaction for all PEV owners. This paper proposes an online dynamically optimized algorithm for optimal variable charge-rate scheduling of PEVs based on coordinated aggregated particle swarm optimization (CAPSO). The online algorithm is updated at regular intervals of Δt = 5 min to maximize the customers’ satisfactions for all PEV owners based on their requested plug-out times, requested battery state of charges (SOCReq) and willingness to pay the higher charging energy prices. The algorithm also ensures that the distribution transformer is not overloaded while grid losses and node voltage deviations are minimized. Simulation results for uncoordinated PEV charging as well as CAPSO with fixed charge-rate coordination (FCC) and variable charge-rate coordination (VCC) strategies are compared for a 449-node network with different levels of PEV penetrations. The key contributions are optimal VCC of PEVs considering battery modeling, chargers’ efficiencies and customer satisfaction based on requested plug-out times, driving pattern, desired final SOCs and their interest to pay for energy at a higher rate.
A new topology for doubly fed induction generator to improve the overall performance of wind energy conversion system
- Authors: Khamaira, Mahmoud , Abu-Siada, Ahmed , Islam, Syed , Masoum, Mohammad
- Date: 2014
- Type: Text , Journal article
- Relation: Elixir International Journal: Electrical Engineering Vol. 73, no. (2014), p. 26432-26435
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- Description: Doubly Fed Induction Generators (DFIGs) are currently extensively used in variable speed wind power plants due to their superior advantages that include reduced converter rating, low cost, reduced losses, easy implementation of power factor correction schemes, variable speed operation and four quadrants active and reactive power control capabilities. On the other hand, DFIG sensitivity to grid disturbances, especially for voltage sags represents the main disadvantage of the equipment. In this paper, a coil is proposed to be integrated within the DFIG converters to improve the overall performance of a DFIGbased wind energy conversion system (WECS). The charging and discharging of the coil are controlled by controlling the duty cycle of the switches of the dc-dc chopper. Simulation results reveal the effectiveness of the proposed topology in improving the overall performance of the WECS system under study.
Digital implementation of a fault emulator for transient study of power transformers used in grid connection of wind farms
- Authors: Mesbah, Mohsen , Moses, Paul , Islam, Syed , Masoum, Mohammad
- Date: 2013
- Type: Text , Journal article
- Relation: IEEE Transactions on Sustainable Energy Vol. 5, no. 2 (2013), p. 646-654
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- Description: A real-time digital hardware simulation tool is developed to study the transient performance of three-phase power transformers used in grid connected wind farms. Using vector-based analysis for generating different voltage components, the fault simulator is capable of emulating a multitude of grid connection disturbances such as voltage sag, voltage swell, voltage unbalance, harmonics, dc-bias, and phase jump. This enables realistic real-time evaluation of power system faults and their impacts on critical components such as the interconnection transformers used in wind farms. In this paper, the proposed fault simulator has been employed to conduct an experimental study of the effects of balanced and unbalanced fault conditions on a three-phase three-leg power transformer. The transient current response of three-phase transformers subject to symmetrical/unsymmetrical faults is a complex issue due to the influences of multiple flux paths interacting within the core as well as ferromagnetic nonlinearities and core-structure asymmetry. So far, existing studies of this behavior have been restricted to computer modeling simulations with limited experimental work performed. The main contributions of this paper are to 1) present a new versatile fault simulator using a space vector modulation control approach to generate typical grid disturbances, and 2) apply the fault emulator to study the transient behavior of three-phase power transformers under various fault conditions common to wind farm interconnection transformers. The paper also discusses design, component selection, digital signal processing (DSP), and implementation aspects.
Time-delay analysis of wide area voltage control considering smart grid contingences in real-time environment
- Authors: Musleh, Ahmed , Muyeen, S. , Al-Durra, Ahmed , Kamwa, Innocent , Masoum, Mohammad , Islam, Syed
- Date: 2018
- Type: Text , Journal article
- Relation: IEEE Transactions on Industrial Informatics Vol. 14, no. 3 (2018), p. 1242-1252
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- Description: IEEE This paper addresses the time delay effects of the wide area monitoring and control systems (WAMCS) in smart power grids which may critically impact system stability. The main purpose is to conduct a detailed delay analysis of the WAMCS in case of grid contingences. This analysis is performed via an advanced WAMCS testbed where a wide area controller (WAC) for a flexible AC transmission system (FACTS) device is implemented. The real-time measurements for the WAC are collected using phasor measurements units (PMU). The testbed is resulted from an interface of four main segments known as the WAC, the actual FACTS device, the local area controller, and the power grid system along with the PMUs are simulated via real time digital simulator (RTDS). To mimic the real case scenario both hardware-in-the-loop (HIL) and software-in-the-loop (SIL) schemes are adopted in the experimental testbed, considering time delay effects. The results obtained clarify the effect of delay in WAMCS in case of smart grid contingences.