Sajjad Abedi | Purdue University (original) (raw)

Papers by Sajjad Abedi

Handbook of Electric Power Calculations, Fourth Edition, McGraw-Hill Education, 2015

IEEE Transactions on Power Systems, 2017

Hourly wind power ramps in ERCOT are studied by applying extreme value theory. Mean excess plot r... more Hourly wind power ramps in ERCOT are studied by applying extreme value theory. Mean excess plot reveals that the tail behavior of large hourly wind power ramps indeed follows a generalized Pareto distribution. The location, shape, and scale parameters of generalized Pareto distribution are then determined by using mean excess plot and the least square technique, from which risk measures including α quantile value at risk and conditional value at risk are calculated.

IEEE Transactions on Power Systems, 2018

Large-scale and ubiquitous penetration of wind power generation to power systems necessitates mor... more Large-scale and ubiquitous penetration of wind power generation to power systems necessitates more conservative provision of system reliability by ensuring adequately committed reserve and observance of transmission constraints. In addition, wind power curtailment due to the technical limitations of system operations, such as transmission congestion, should be efficiently mitigated. To this aim, this paper presents a congestion risk-aware unit commitment formulation in a two-settlement market environment. The uncertainty impact of multicorrelated wind power and contingencies on the risk of transmission congestion for each line, called the Line Transfer Margins (LTM), is incorporated using basic statistical data on the nodal wind power forecast and probability of credible line-outages across the system. The LTMs, formulated free of any distributional assumptions, collectively provide a measure for transmission reserves, which effectively mitigate the likelihood of transmission congestion, reserve undeliverability, and wind power curtailment in the real-time economic dispatch. The effectiveness of the proposed approach is verified through comparative case studies on IEEE RTS-96 for various wind power and LTM scenarios.

IEEE Access, 2018

With the deepening penetration of renewable resources worldwide, power system operators are faced... more With the deepening penetration of renewable resources worldwide, power system operators are faced with emerging challenges, e.g., the increase of operating risks due to the volatility and uncertainty of wind and solar power. To efficiently identify the operational limit violations, a switch from deterministic to stochastic framework for assessing the system security, which could manage various types of uncertainties, has been advocated in this paper. The established model is based on an improved probabilistic load flow, which is adapted to incorporate the steady-state behavior of frequency regulation. An efficient importance sampling (IS) technique is also developed to speed up the crude Monte Carlo (MC) simulation in estimating the low probability of violations of security constraints. Extensive computational experiments on both the IEEE 14-bus test case and a simplified regional system show that the proposed IS estimator makes significant enhancement to the crude MC in the computational efficiency and has better numerical performance as compared with other IS schemes.

IEEE, 2018

Currently, most ISOs adopt offer cost minimization (OCM) auction mechanism which minimizes the to... more Currently, most ISOs adopt offer cost minimization (OCM) auction mechanism which minimizes the total offer cost, and then, a settlement rule based on either locational marginal prices (LMPs) or market clearing price (MCP) is used to determine the payments to the committed units, which is not compatible with the auction mechanism because the minimized cost is different from the payment cost calculated by the settlement rule. This inconsistency can drastically increase the payment cost. On the other hand, payment cost minimization (PCM) auction mechanism eliminates this inconsistency; however, PCM problem is a nonlinear self-referring NP-hard problem which poses grand computational burden. In this paper, a mixed-integer nonlinear programing (MINLP) formulation of PCM problem are presented to address additional complexity of fast-growing penetration of Vehicle-to-Grid (V2G) in the price-based market clearing problem, and a solution method based on the generalized benders decomposition (GBD) is then proposed to solve the V2G-integrated PCM problem, and its favorable performance in terms of convergence and computational efficiency is demonstrated using case studies. The proposed GBD-based method can handle scaled-up models with the increased number of decision variables and constraints which facilitates the use of PCM mechanism in the market clearing of large-scale power systems. The impact of using V2G technologies on the OCM and PCM mechanisms in terms of MCPs and payments is also investigated, and by using numerical results, the performances of these two mechanisms are compared.

2016 North American Power Symposium (NAPS), 2016

2015 IEEE Power & Energy Society General Meeting, 2015

2015 IEEE Power & Energy Society Innovative Smart Grid Technologies Conference (ISGT), 2015

ISRN Renewable Energy, 2011

Wind and solar (photovoltaic) power generations have rapidly evolved over the recent decades. Eff... more Wind and solar (photovoltaic) power generations have rapidly evolved over the recent decades. Efficient and reliable planning of power system with significant penetration of these resources brings challenges due to their fluctuating and uncertain characteristics. In this ...

Energy Conversion and Management, 2015

Optimal planning of energy systems greatly relies upon the models utilized for system components.... more Optimal planning of energy systems greatly relies upon the models utilized for system components. In this paper, a thorough modeling framework for photovoltaic (PV) power plants is developed for application to operation and planning studies. The model is a precise and flexible one that reflects all the effective environmental and weather parameters on the performance of PV module and inverter, as the main components of a PV power plant. These parameters are surface radiation, ambient temperature and wind speed. The presented model can be used to estimate the plant's output energy for any time period and operating condition. Using a simple iterative process, the presented method demonstrates fast and accurate convergence by merely using the limited information provided by manufacturers. The results obtained by the model are verified by the results of System Advisor Model (SAM) and RETScreen in various operational scenarios. Furthermore, comparison of the simulation results with a real power plant outputs and the comparative statistical error analysis confirm that our calculation procedure merits over SAM and RETScreen, as modern and popular commercial PV simulation tools.

IEEE Transactions on Power Systems, 2014

ABSTRACT The DC power flow model is in widespread utilization in electricity-market applications ... more ABSTRACT The DC power flow model is in widespread utilization in electricity-market applications and contingency analysis. The presented versions of this model can be classified into two categories: state-dependent, or Hot-Start, models and state-independent, or Cold-Start, models. A reasonable accuracy is reported in the literature regarding Hot-Start models as they take into account branch losses and bus voltages by using available base point. On the contrary, due to the absence of base point in Cold-Start models, branch losses must be either neglected or guessed (which is an uncertain precautionary measure), or evaluated by a cumbersome iteration process. In addition, the bus voltage profiles are inevitably considered to be flat. Hence, the accuracy of available Cold-Start models in different circumstances remains of great concern. This paper addresses this concern and unveils a new Cold-Start model that does not rely on a risky assumption. In other words, there will be no lossless or flat voltage profile assumption in the presented approach whereas the equations remain linear. Besides, the exact effect of the net reactive loads on phase angles is considered and, consequently, the reactive power balance equations are reflected in the model for the first time.

The locational marginal pricing (LMP) methodology is a well-known strategy in electricity market ... more The locational marginal pricing (LMP) methodology is a well-known strategy in electricity market transactions. In this structure, the active losses and transmission congestion are the key factors discriminating the nodal prices. To generate correct economic signals by LMPs, a realistic modeling of power system is required. Generally, power system and loads are assumed to be linear and the resultant conducting losses are modeled considering pure sinusoidal waveforms of currents and voltages. However, most real power systems may be polluted with some orders of harmonic frequencies due to the presence of nonlinearities. Although the magnitudes of harmonics relative to power frequency variables may be considered negligible, the present paper reveals that these harmonics, even below the standard levels, have considerable effects on the overall value of energy trades, and particularly on nodal prices and Financial Transmission Rights (FTRs). As the study objective, a new model is developed to allocate the harmonic losses in the Optimal Power Flow (OPF) and LMP problems. To assess the LMP and FTR variations with respect to harmonic status, the proposed concept is illustrated with 6-bus and 24-bus test systems. The changes made by consideration of harmonic losses show increasing gap between total generation revenue and consumption cost and therefore, expansion in transmission side revenue.

In this paper, cost minimization of a stand-alone hybrid energy system including photovoltaics, w... more In this paper, cost minimization of a stand-alone hybrid energy system including photovoltaics, wind turbines and fuel cells through the overall 20-years life time of the system is performed considering reliability constraints. The cost function of the system includes investment cost, operation and maintenance cost and the cost associated with loss of load. The applied wind speed data and solar irradiation data belongs to a region in north west of Iran. To handle the mixed integer nonlinear optimization problem, differential evolutionary algorithm is applied. To provide a time efficient solution process for the optimization problem, an approximated reliability model is used for reliability assessment. Numerical results depict that while the overall system cost is optimized, the reliability indices are within a satisfactory bound with regard to the reliability standards. Comparative results with particle swarm optimization (PSO) present the efficacy of the proposed algorithm.

With the increasing application of Induction Heating (IH) systems in various industries such as m... more With the increasing application of Induction Heating (IH) systems in various industries such as metallurgy, concerns about the harmonic effects and power quality of the power grid have been involved in the problems facing network operation engineers. This paper presents methods to improve the power quality of induction heating systems. Current Source Parallel Resonant Inverter (CSPRI) is mostly used for IH systems. For three-phase current source IH system a new soft starting method with single tuned passive filters is used to reduce sag voltage and harmonic distortions. For single phase applications a new topology is presented to reduce harmonic distortions. In this paper the current source induction heating system is modeled and the transient and steady state behaviors of the system are simulated. For single phase topology a low power laboratory prototype is implemented with operating frequency of 60 kHz; the experimental results and simulation results are in good agreement.

Renewable and Sustainable Energy Reviews

The power management strategy (PMS) plays an important role in the optimum design and efficient u... more The power management strategy (PMS) plays an important role in the optimum design and efficient utilization of hybrid energy systems. The power available from hybrid systems and the overall lifetime of system components are highly affected by PMS. This paper presents a novel method for the determination of the optimum PMS of hybrid energy systems including various generators and storage units. The PMS optimization is integrated with the sizing procedure of the hybrid system. The method is tested on a system with several widely used generators in off-grid systems, including wind turbines, PV panels, fuel cells, electrolyzers, hydrogen tanks, batteries, and diesel generators. The aim of the optimization problem is to simultaneously minimize the overall cost of the system, unmet load, and fuel emission considering the uncertainties associated with renewable energy sources (RES). These uncertainties are modeled by using various possible scenarios for wind speed and solar irradiation based on Weibull and Beta probability distribution functions (PDF), respectively. The differential evolution algorithm (DEA) accompanied with fuzzy technique is used to handle the mixed-integer nonlinear multi-objective optimization problem. The optimum solution, including design parameters of system components and the monthly PMS parameters adapting climatic changes during a year, are obtained. Considering operating limitations of system devices, the parameters characterize the priority and share of each storage component for serving the deficit energy or storing surplus energy both resulted from the mismatch of power between load and generation. In order to have efficient power exploitation from RES, the optimum monthly tilt angles of PV panels and the optimum tower height for wind turbines are calculated. Numerical results are compared with the results of optimal sizing assuming pre-defined PMS without using the proposed power management optimization method. The comparative results present the efficacy and capability of the proposed method for hybrid energy systems.