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Hossein Lotfi - IEEE Xplore Author Profile

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This paper introduces the capacity analysis commitment tool (CACT) developed by the New York Independent System Operator, Inc. (NYISO) to help operators in the control room with a decision-making process when there is a need to commit additional capacity due to unforeseen real-time (RT) events after day-ahead (DA) schedules are published. CACT encompasses commitment scheduler and commitment shift ...Show More
Load shedding is a method in power distribution networks that is used to prevent problems caused by lack of energy or excessive demand for the power grid. When the demand exceeds the current production rate or in the case of a shortage of power generation resources, load shedding can prevent problems such as voltage reduction, frequency reduction, phase imbalance, and even power outages. Increasin...Show More
A high voltage direct current (HVDC) line is proposed to be built between upstate New York and New York City (NYC), with both ends inside the control area of the New York Independent System Operator, Inc. (NYISO). This is the first fully controllable internal HVDC line in the United States to be modeled in the energy market. This paper proposes a generalized locational marginal price (LMP)-based e...Show More
Today, energy is one of the most important human needs. Due to the limitation of fossil fuel resources, the issue of controlling energy costs, reducing the effects of energy conversion and consumption on the environment, reducing power losses and operating costs is of great importance. In this study, the problem of minimizing power loss and operating cost in the presence of distributed generation ...Show More
The operation of the power distribution network is influenced by many factors, such as various faults, network maneuvers, and out-of-service equipment. Therefore, reducing the outage time, increasing the reliability, and, as a result, the satisfaction of the subscribers is one of the important goals of the power distribution company. Protective switches such as reclosers and sectionalizers reduce ...Show More
This paper proposes two potential transmission constraint screening processes (TCSPs) for consideration with respect to the energy market administered by the New York Independent System Operator, Inc. (NYISO). The proposed TCSPs are intended to dynamically prevent duplicate and redundant transmission shortages from being priced by the graduated transmission shortage mechanism employed in the NYISO...Show More
The distribution feeder reconfiguration represents a major process of operation in the distribution system utilized to enhance grid performance. Given disparities in the electricity price as well as smart networks' load pattern, the distribution system's operational problems are much more time-dependent and more complex than before. For this purpose, the dynamic distribution reconfiguration with d...Show More
The dependence of the instantaneous generation output of wind turbines on wind speed and wind unevenness as a geographical phenomenon have made wind generators unpredictable power plants. Fluctuations in wind speed can lead to fluctuations in the power fed into the grid by the wind farm. As a result of these fluctuations, transient over voltages occur in the grid and especially in loads near the P...Show More
This study proposes, a novel approach for optimal energy management's problem and capacitor switching in the distribution network at the presence of distributed generators, energy storage units and solar photovoltaic arrays. Modern distribution networks, in addition to the importance of economic issues, must operate at an acceptable level of system reliability, Failure to pay attention to the reli...Show More
Distribution feeder reconfiguration (DFR) is an optimization problem in distribution system which is used to improve the distribution network performance by changing the status of switches. In this study, a multi-objective framework is presented for dynamic distribution feeder reconfiguration (DDFR) along with capacitor allocation problem in distribution network over multiple time intervals consid...Show More
In distribution systems, feeder reconfiguration and capacitor switching can lead to power loss reduction, reliability improvement and keep the voltage within its allowable range. Distribution feeder reconfiguration (DFR) is an optimization problem in distribution systems which is used to improve the distribution network performance by changing the status of switches. In this study, a multi-objecti...Show More
This paper proposes a distributed energy storage planning model for hybrid AC/DC microgrids. It is assumed that there is a hybrid AC/DC microgrid with various distributed generators (DGs) and a combination of AC and DC loads, without a distributed energy storage (DES). The optimal power and energy size and location of the DES unit are determined to minimize the microgrid total cost, which includes...Show More
This paper proposes a coordinated optimal scheduling model for hybrid AC/DC microgrids. The objective of the proposed model is to minimize the total microgrid operation cost when considering interactions between AC and DC subsystems of the microgrid network. Nonlinear power flow equations for AC and DC networks have been linearized through a proposed model to enable formulating the problem by mixe...Show More
Generally the generation units in the traditional structure of the electricity industry try to minimize their costs. However, in a deregulated environment, generation units are looking to maximize their profits in a competitive power market. Optimum generation planning in a such structure is urgent. This paper presents a new method of solving economic dispatch in the competitive electricity market...Show More
We report on the characterization of narrow-bandgap (Eg ≈ 0.4 eV, at 300 K) interband cascade thermophotovoltaic (TPV) devices with InAs/GaSb/AlSb type-II superlattice absorbers. Two device structures with different numbers of stages (two and three) were designed and grown to study the influence of the number of stages and absorber thicknesses on the device performance at high temperatures (300-34...Show More

AC Versus DC Microgrid Planning

Hossein Lotfi;Amin Khodaei

IEEE Transactions on Smart Grid
Year: 2017 | Volume: 8, Issue: 1 | Journal Article |
Cited by: Papers (356)
This paper presents a microgrid planning model for determining the optimal size and the generation mix of distributed energy resources (DERs), as well as the microgrid type, i.e., ac or dc. Considering the growing ratio of dc loads and DERs, dc microgrids could be potentially more beneficial than ac microgrids by avoiding the need to synchronize generators, reducing the use of converters, facilita...Show More
We report on the room-temperature operation of a high-speed mid-infrared optical system (f3-dB ≈ 0.5 GHz). This system consists of an efficient interband cascade laser and an uncooled high-performance interband cascade infrared photodetector.Show More
A hybrid microgrid planning model is proposed in this paper to determine the least-cost distributed energy resource (DER) size and generation mix, the type of each feeder in the microgrid distribution network (i.e., AC or DC), and the optimal location of each selected DER. The objective of the microgrid planning problem is to minimize the total planning cost, including the investment and operation...Show More
Extreme weather events can potentially cause multiple component outages in power systems and result in electricity supply interruptions. The installation of microgrids in proper places in power systems can be considered as a viable solution to this problem which is under investigation by many electric utilities in the Unites States. Considering this issue and the growing number and intensity of ex...Show More
The levelized cost of energy (LCOE) provides an effective tool to compare different energy resource technologies with different lifetimes, cost structures, and capacity factors from an economical perspective. This paper follows simple and limited discussions in LCOE calculations of individual generation units and extends it to a sophisticated model to determine LCOE of integrated generation units....Show More
Uncertainty considerations in microgrid operation and planning are of significant importance as uncertain factors can potentially alter the operator's decisions. New mathematical approaches, such as robust optimization, are commonly adopted to capture uncertainties and ensure practicality. However, this added practicality is at the expense of increased problem size and computational complexity. Th...Show More
Locate and determine the optimal capacity shunt capacitors in to reduce power losses and improve voltage profile and use the maximum capacity of transmission lines, one of the common problems in the design and control of power systems. Shunt capacitors are used to power loss reduction and improving voltage profile in order to utilize maximum capacity of transfer lines. This paper proposed a novel ...Show More
This article provides the reliability of wind energy, Due to the increasing use of wind power plants in the world and the susceptibility of the plant to check the reliability of the various factors seems necessary. In this paper, test network reliability indexes are examined in the presence of wind farms. Reliability indices LOLE (Loss of Load Expectation) and EENS (Expected Energy Not Supplied) e...Show More
The significant benefits associated with microgrids have led to vast efforts to expand their penetration in electric power systems. Although their deployment is rapidly growing, there are still many challenges to efficiently design, control, and operate microgrids when connected to the grid, and also when in islanded mode, where extensive research activities are underway to tackle these issues. It...Show More
Multi-stage Interband Cascade Photovoltaic (ICPV) devices with a room-temperature cutoff wavelength of ~3 μm were investigated. These devices were characterized at various temperatures under illumination from both a blackbody source and an interband cascade (IC) laser (emission wavelength of ~2.86 μm). Under laser illumination (8.0 W/cm2) an open-circuit voltage (Voc) of 447 mV with a short-circui...Show More