Mohammad E. Khodayar

Integration of High Reliability Distribution System in Microgrid Operation

In this paper, the application of high reliability distribution system (HRDS) in the economic operation of a microgrid is studied. HRDS, which offers higher operation reliability and fewer outages in microgrids, is applied to looped networks in distribution systems. The microgrid model in this study is composed of distributed energy resources (DER) including distributed generation (DG), controllable loads, and storage. The microgrid would utilize the local DER as well as the main grid for supplying its hourly load economically which is subject to power quality and reliability requirements. The HRDS implemented at Illinois Institute of Technology (IIT) is used as a case study along with the local DER to increase the load point reliability and decrease the operation cost of the IIT microgrid. The availability of distribution lines, main grid supply, and microgrid generation is considered using the Markov chain Monte Carlo simulation in the microgrid scenarios. The reliability indices based on frequency and duration of outages are measured at the microgrid level and the load point level, and the potential system enhancements are discussed for improving the economic operation of the IIT microgrid.

Enhancing the Dispatchability of Variable Wind Generation by Coordination With Pumped-Storage Hydro Units in Stochastic Power Systems

The ever-increasing penetration of variable wind energy in power systems affects the hourly dispatch of thermal power generation in electricity markets. The variability of wind energy, which makes the wind energy non-dispatchable and difficult to control, could bring significant challenges to power system operators. The hourly coordination of wind power generation units with pumped-storage hydro (PS) generation could relieve the variability of wind energy and increase its dispatchability. The wind-PS coordination is based on the application of stochastic security-constrained unit commitment (stochastic SCUC). In this study, the coordinated hourly bus-level scheduling of wind-PS is compared with the coordinated system-level operation strategies in the day-ahead scheduling of power systems.

Only Connect: Microgrids for Distribution System Restoration

Electricity infrastructure is the cornerstone of every industrialized nation in the world. As the utility grid ages and the demand for electricity grows, the impact of major interruptions of the electricity infrastructure will be more intense. Costly power outages throughout the world caused by natural disasters such as floods and hurricanes have highlighted the importance of reinforcing the electricity infrastructure. A recent study conducted for the U.S. Department of Energy indicated that sustained power interruptions (those lasting more than 5 min) in the United States incur costs of more than US

Hourly Demand Response in Day-Ahead Scheduling Considering Generating Unit Ramping Cost

26 billion dollars annually. Power outages caused by Hurricanes Sandy and Katrina in the United States threw into notice the crucial role of smart grid technology and the need for further investments in more comprehensive data communication and distribution management systems, distributed energy resources, energy storage facilities, additional automation, and further migration toward decentralized operations for the largely centralized power grid.

Adaptive Protection System for Microgrids: Protection practices of a functional microgrid system.

This paper proposes a day-ahead scheduling model in which the hourly demand response (DR) is considered to reduce the system operation cost and incremental changes in generation dispatch when the ramping cost of thermal generating units is considered as penalty in day-ahead scheduling problem. The power output trajectory of a thermal generating unit is modeled as a piecewise linear function. The day-ahead scheduling is formulated as a mixed-integer quadratically constrained programming (MIQCP) problem with quadratic energy balance constraint, ramping cost, and DR constraints. A Lagrangian relaxation (LR) based method is applied to solve this problem. Numerical tests are conducted on a 6-bus system and the modified IEEE 118-bus system. The results demonstrate the merits of the proposed scheduling model as well as the impact of introducing ramping costs as penalty and DR as incentives in the day-ahead scheduling of power systems.

Using genetic alghoritm for distributed generation allocation to reduce losses and improve voltage profile

Distributed energy resources (DERs) offer on-site generation at consumption points, which are expected to change the conventional concept of central power generation. DER integration reduces transmission losses and enhances the operation reliability of distribution systems. However, distribution systems are traditionally designed as passive networks in which large DER penetrations representing bidirectional power flows and topology-dependent fault currents could affect protection devices, cause danger to the maintenance personnel, and result in uncontrollable under-/overvoltage and frequency. IEEE Standard 1547 requires DER units to stop energizing the distribution system when the system is de-energized due to faults.

Cutting Campus Energy Costs with Hierarchical Control: The Economical and Reliable Operation of a Microgrid

This paper presents a method for the optimal allocation of Distributed generation in distribution systems. In this paper, our aim would be optimal distributed generation allocation for voltage profile improvement and loss reduction in distribution network. Genetic Algorithm (GA) was used as the solving tool, which referring two determined aim; the problem is defined and objective function is introduced. Considering to fitness values sensitivity in genetic algorithm process, there is needed to apply load flow for decision-making. Load flow algorithm is combined appropriately with GA, till access to acceptable results of this operation. We used MATPOWER package for load flow algorithm and composed it with our Genetic Algorithm. The suggested method is programmed under MATLAB software and applied ETAP software for evaluating of results correctness. It was implemented on part of Tehran electricity distributing grid. The resulting operation of this method on some testing system is illuminated improvement of voltage profile and loss reduction indexes.

Risk-Constrained Coordination of Cascaded Hydro Units With Variable Wind Power Generation

in this article, we discuss microgrid objectives and present options for microgrid operations and their monitoring and control in the context of a functional system at the illinois institute of technology (iit) in Chicago. the microgrid represents a multitier hierarchical control of self-sustaining energy infrastructure with islanding and resynchronization, self-healing, and demand response capabilities. the intelligent high-reliability distribution system (HRDS) at iit is equipped with phasor measurement units (PMUs) for real-time monitoring, nondispatchable renewable energy production, as well as conventional and dispatchable energy resources.

Electric Vehicle Mobility in Transmission-Constrained Hourly Power Generation Scheduling

This paper presents a stochastic hourly coordination strategy for wind units and cascaded hydro generation as storage to firm up the hourly dispatch in a generating company (GENCO). The proposed strategy is based on the stochastic price-based unit commitment (Stochastic PBUC) formulation which includes wind energy imbalance charges. The forecast errors of electricity market price and wind speed are simulated with the Monte Carlo method via a scenario approach. The risk-aversion constraints are considered for limiting a GENCOs financial risks when considering uncertain wind power generation. The proposed optimization model is solved by mixed-integer linear programming (MIP) and illustrative examples examine the effectiveness of the proposed risk-based coordination model for optimizing a GENCOs payoff.

Stochastic Price-Based Coordination of Intrahour Wind Energy and Storage in a Generation Company

The proposed approach evaluates the effect of integrating a large number of electric vehicles (EVs) on power grid operation and control. The EV fleets could serve as electricity load when drawing energy from the grid and as energy storage (vehicle-to-grid) when delivering energy to the grid. The paper considers two operating modes for EV fleets which are consumer-controlled and grid-controlled. The power grid generation mix represents a multitude of units including thermal, hydro, and wind. The paper considers the impact of EV battery utilization on offsetting the hourly variability of wind generation units in transmission-constrained power grids. The paper considers charging/discharging schedule of EV batteries and consumer driving requirements on the optimal hourly transmission-constrained commitment and dispatch of generation units in the day-ahead scheduling. The hourly solution of the proposed method will minimize the cost of supplying the hourly load while satisfying the temporal constraints of individual components in power grids.