Waterloo, Canada

University of Waterloo

uwaterloo.ca/
Waterloo, Canada

University of Waterloo is a public research university whose main campus is located in Waterloo, Ontario, Canada. The main campus is located on 400 hectares of land in Uptown Waterloo, adjacent to Waterloo Park. The university offers a wide variety of academic programs, which is administered by six faculties, and three affiliated university colleges. Waterloo is a member of the U15, a group of research-intensive universities in Canada. Wikipedia.

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Atwa Y.M.,University of Waterloo | El-Saadany E.F.,University of Waterloo | Salama M.M.A.,University of Waterloo | Seethapathy R.,Hydro One Inc
IEEE Transactions on Power Systems | Year: 2010

It is widely accepted that renewable energy sources are the key to a sustainable energy supply infrastructure since they are both inexhaustible and nonpolluting. A number of renewable energy technologies are now commercially available, the most notable being wind power, photovoltaic, solar thermal systems, biomass, and various forms of hydraulic power. In this paper, a methodology has been proposed for optimally allocating different types of renewable distributed generation (DG) units in the distribution system so as to minimize annual energy loss. The methodology is based on generating a probabilistic generation-load model that combines all possible operating conditions of the renewable DG units with their probabilities, hence accommodating this model in a deterministic planning problem. The planning problem is formulated as mixed integer nonlinear programming (MINLP), with an objective function for minimizing the system's annual energy losses. The constraints include the voltage limits, the feeders' capacity, the maximum penetration limit, and the discrete size of the available DG units. This proposed technique has been applied to a typical rural distribution system with different scenarios, including all possible combinations of the renewable DG units. The results show that a significant reduction in annual energy losses is achieved for all the proposed scenarios. © 2009 IEEE.

Document Keywords (matching the query): solar energy, energy loss, renewable energy source, distributed generation, energy conservation, distributed generation units, electron energy loss spectroscopy, solar power generation, sustainable energy supply, renewable energy technologies, energy dissipation.


Olivares D.E.,University of Waterloo | Canizares C.A.,University of Waterloo | Kazerani M.,University of Waterloo
IEEE Transactions on Smart Grid | Year: 2014

This paper presents the mathematical formulation of the microgrid's energy management problem and its implementation in a centralized Energy Management System (EMS) for isolated microgrids. Using the model predictive control technique, the optimal operation of the microgrid is determined using an extended horizon of evaluation and recourse, which allows a proper dispatch of the energy storage units. The energy management problem is decomposed into Unit Commitment (UC) and Optimal Power Flow (OPF) problems in order to avoid a mixed-integer non-linear formulation. The microgrid is modeled as a three-phase unbalanced system with presence of both dispatchable and non-dispatchable distributed generation. The proposed EMS is tested in an isolated microgrid based on a CIGRE medium-voltage benchmark system. Results justify the need for detailed three-phase models of the microgrid in order to properly account for voltage limits and procure reactive power support. © 2014 IEEE.

Document Keywords (matching the query): energy management, energy management system, distributed power generation, energy management systems, energy storage unit.


Zidan A.,University of Waterloo | El-Saadany E.F.,University of Waterloo
Energy | Year: 2013

The interconnection of renewable energy sources with distribution systems is attracting increasing interest because these renewable sources are inexhaustible and nonpolluting. Wind and photovoltaic are among the most mature of these energy sources, and their penetration continues to increase. In this paper a method based on GA (genetic algorithm) is presented to investigate the distribution system reconfiguration problem taking into consideration the effect of load variation and the stochastic power generation of renewable DG (distributed generators units). The presented method determines the annual distribution network reconfiguration scheme considering switching operation costs in order to minimize annual energy losses by determining the optimal configuration for each season of the year. The uncertainties related to DG power and varying load are considered by the creation of a probabilistic generation-load model that combines all possible operating conditions of the renewable DG units with the probability of their occurrence, followed by the incorporation of this model into the reconfiguration problem. The constraints include the voltage limits, the line current limits, the radial topology, and feeding of all loads. In order to evaluate the effectiveness of the proposed method, both balanced and unbalanced distribution systems are used as case studies. © 2013 Elsevier Ltd.

Document Keywords (matching the query): distributed generation, renewable energy source, energy loss reduction, distributed power generation, energy resource, power generation, energy dissipation.


Atwa Y.M.,University of Waterloo | El-Saadany E.F.,University of Waterloo | Guise A.-C.,University of Waterloo
IEEE Transactions on Power Systems | Year: 2010

Keen interest in the development and utilization of wind-based distributed generation (DG) has been currently observed worldwide. The reliability impact of this highly variable energy source is an important aspect that needs to be assessed as wind power penetration becomes increasingly significant. Distribution system adequacy assessment including wind-based DG units during different modes of operation is described in this paper. Monte Carlo simulation (MCS) and analytical technique are used in this work with a new implementation of the islanding mode of operation in the assessment. The results show that there is no significant difference between the outcomes of the two proposed techniques; however, MCS requires much longer computational time. Moreover, the effect of islanding appears in the improvement of the loss of load expectation (LOLE) and loss of energy expectation (LOEE). © 2009 IEEE.

Document Keywords (matching the query): distributed generations, loss of energy, wind energy, energy source, distributed generation.


Mohamed Y.A.-R.I.,University of Alberta | El-Saadany E.F.,University of Waterloo
IEEE Transactions on Energy Conversion | Year: 2011

This paper presents a robust natural-frame-based interfacing scheme for grid-connected distributed generation inverters. The control scheme consists of a dead-beat line-voltage sensorless natural-frame current controller, adaptive neural network (NN)-based disturbance estimator, and robust sensorless synchronization loop. The estimated uncertainty dynamics provide the necessary energy shaping in the inverter control voltage to attenuate grid-voltage disturbances and other voltage disturbances caused by interfacing parameter variation. In addition, the predictive nature of the estimator has the necessary phase advance to compensate for system delays. The self-learning feature of the NN adaptation algorithm allows feasible and easy adaptation design at different grid disturbances and operating conditions. The fact that converter synchronization is based on the fundamental grid-voltage facilitates the use of the estimated uncertainty to extract the position of the fundamental grid-voltage vector without using voltage sensors. Theoretical analysis and comparative evaluation results are presented to demonstrate the effectiveness of the proposed control scheme. © 2011 IEEE.

Document Keywords (matching the query): energy shaping, distributed power generation, distributed generation dg.


Atwa Y.M.,University of Waterloo | El-Saadany E.F.,University of Waterloo
IET Renewable Power Generation | Year: 2011

Recent development in small renewable/clean generation technologies such as wind turbines, photovoltaic, fuel cells, microturbines and so on has drawn distribution utilities' attention to possible changes in the distribution system infrastructure and policy by deploying distributed generation (DG) in distribution systems. In this study, a methodology has been proposed for optimally allocating wind-based DG units in the distribution system so as to minimise annual energy loss. The methodology is based on generating a probabilistic generation-load model that combines all possible operating conditions of the wind-based DG units and load levels with their probabilities, hence accommodating this model in a deterministic planning problem. The planning problem is formulated as mixed integer non-linear programming (MINLP), with an objective function for the system's annual energy losses minimise. The constraints include voltage limits at different buses (slack and load buses) of the system, feeder capacity, discrete size of the DG units, maximum investment on each bus, and maximum penetration limit of DG units. This proposed technique is applied to a typical rural distribution system and compared to the traditional planning technique (constant output power of DG units and constant peak load profile). © 2010 The Institution of Engineering and Technology.

Document Keywords (matching the query): distributed generations, energy loss, distributed generation, generation technologies, electron energy loss spectroscopy, energy dissipation.


Shaaban M.F.,University of Waterloo | Atwa Y.M.,University of Waterloo | El-Saadany E.F.,University of Waterloo
IEEE Transactions on Power Systems | Year: 2013

This paper proposes a method to evaluate the worth of installing renewable distributed generation (DG) in distribution networks.Moreover, thework optimally allocates theseDGunits in the distribution network to maximize the worth of the connection to the local distribution company (LDC), as well as the customers connected to the system. The proposed methodology helps the LDC to better assess the benefits of the renewable DG units' proposed connections and to identify the optimal buses on which to connect these DG units. The benefits considered in this paper are deferral of upgrade investments, reduction of the cost of energy losses, and reliability improvement, which is represented by the interruption cost reduction. The proposedmethodology takes into consideration the uncertainty and variability associated with the output power of renewableDGaswell as the load variability. The planning problem of determining the optimal location and sizes of DG units is defined as multi-objective mixed integer programming. © 2012 IEEE.

Document Keywords (matching the query): distributed generation, renewable distributed generations, energy dissipation, distributed power generation.


Farag H.E.Z.,University of Waterloo | El-Saadany E.F.,University of Waterloo
IEEE Transactions on Power Systems | Year: 2013

In this paper, a novel cooperative protocol has been proposed to provide a proper voltage control for multiple feeders having a transformer tap-changer (LTC), unbalanced load diversity (station with different feeder loads) and multiple distributed generation (DG) units in each feeder. The proposed cooperative protocol has been defined according to the distributed control technology, where LTC and DG units are considered as control agents. Two conflicting objectives have been defined for each control agent. The first objective aims to achieve the system requirements by minimizing the voltage deviation and the second objective aims to achieve the device requirements by reducing the tap operation andmaximizing the energy capture for LTC and DG units, respectively. The interior structures of the control agents and the communication acts between them have been designed to achieve the best compromise between the two objectives of each control agent. The effectiveness of the proposed cooperative scheme has been verified via different case studies. © 2012 IEEE.

Document Keywords (matching the query): distributed control, distributed power generation, distributed generation dg.


Atwa Y.M.,University of Waterloo | El-Saadany E.F.,University of Waterloo
IEEE Transactions on Power Systems | Year: 2010

Environmental concerns and fuel cost uncertainties associated with the use of conventional energy sources have resulted in rapid growth in the amount of wind energy connected to distribution grids. However, based on Ontario's standard offer program (SOP), the utility has the right to curtail (spill) wind energy in order to avoid any violation of the system constraints. This means that any increase in wind energy production over a specific limit might be met with an increase in the wind energy curtailed. In spite of their cost, energy storage systems (ESSs) are considered to be a viable solution to this problem. This paper proposes a methodology for allocating an ESS in a distribution system with a high penetration of wind energy. The ultimate goal is to maximize the benefits for both the DG owner and the utility by sizing the ESS to accommodate all amounts of spilled wind energy and by then allocating it within the system in order to minimize the annual cost of the electricity. In addition, a cost/benefit analysis has been conducted in order to verify the feasibility of installing an ESS from the perspective of both the utility and the DG owner. © 2006 IEEE.

Document Keywords (matching the query): wind energy production, distributed generation, energy storage systems, conventional energy sources, energy storage, wind energy.


Shaaban M.F.,University of Waterloo | Atwa Y.M.,University of Waterloo | El-Saadany E.F.,University of Waterloo
IEEE Transactions on Power Systems | Year: 2013

This paper proposes a novel model to estimate the electric energy consumption of light duty fleet of plug-in electric vehicles (PEVs). This model can be used to evaluate the impacts of plugging such loads in distribution networks. Both vehicles users' habits and diversity of usage are considered in the presented model, as well as different electric ranges and ambient temperature effect. Moreover, the paper proposes a method to optimally allocate distributed generation (DG) units in the distribution network to mitigate the impacts of high penetration of PEVs. The proposed model shall help the local distribution companies (LDC) to better assess the expected effects of PEVs on their networks and evaluate the required upgrades. Furthermore, the proposed DG allocation methodology helps to identify the optimal buses on which to connect these DG units in the presence of high PEVs penetration. A genetic based approach is utilized for the planning problem of determining the optimal locations and sizes of DG units, which is defined as a multi-objective mixed integer programming. © 2012 IEEE.

Document Keywords (matching the query): energy utilization, distributed generation units, electric energy consumption, distributed power generation.

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