Mahyar Zarghami - Academia.edu (original) (raw)

Papers by Mahyar Zarghami

La presente invention se rapporte a une protection contre une instabilite de la tension d'un ... more La presente invention se rapporte a une protection contre une instabilite de la tension d'un systeme d'alimentation electrique qui est mise en œuvre par determination d'un changement de la puissance injectee dans une region digne d'interet dans le systeme d'alimentation electrique sur la base des mesures de puissance synchronisees realisees a partir de differents points d'injection de puissance de la region digne d'interet (200) et par determination d'un changement de la puissance absorbee par une ou plusieurs charges dans la region digne d'interet sur la base des mesures de puissance synchronisees realisees a partir de differents points de charge de la region digne d'interet (210). Un changement de la perte de puissance de la region digne d'interet est determine sur la base de la difference entre le changement de la puissance injectee dans la region digne d'interet et le changement de la puissance absorbee par la region digne d'in...

2016 North American Power Symposium (NAPS), 2016

This paper focuses on the application of BESS (Battery Energy Storage Systems) in improved operat... more This paper focuses on the application of BESS (Battery Energy Storage Systems) in improved operation of distribution grids that are highly penetrated with PV (Photovoltaic) systems. The paper features a state-space based model for BESS and implements a simple and effective approach for peak load shaving by considering device constraints. The grid-connected PV+BESS system proposed in this work contains bidirectional DC/DC and AC/DC converters and batteries, and is capable of simultaneous control of active power, reactive power, and DC-link voltage. In this work, an energy management strategy with the goal of peak-shaving has been proposed, which also considers degradation and ageing limits of the batteries. Simulations have been performed at different battery capacity cases to show the capabilities of the proposed PV+BESS.

2015 IEEE Power & Energy Society General Meeting, 2015

Increased penetration levels of Distributed Generation (DG) can cause steady state and transient ... more Increased penetration levels of Distributed Generation (DG) can cause steady state and transient voltage issues and possible overloading conditions. This paper aims to verify the overvoltage and overloading issues caused by DG at high penetration levels. A typical utility distribution feeder was selected using cluster analysis for simulations. DG at various penetration levels was interconnected at 4 different locations on the feeder. Summer Peak (SP), Partial Peak (PP) and Winter Peak (WP) loading conditions have been studied. Solar Photo-Voltaic (PV) is used as DG for all simulations. Static VAr Compensators (SVC) and Smart Inverters (SI) and their mitigating effects have been reported as possible solutions. Acceptable DG penetration levels have been proposed depending on DG locations and associated voltage or overloading issues. Two special cases, one involving simultaneous high and low voltage conditions and the other related to high voltages at multiple locations have also been studied and reported.

2015 IEEE Power & Energy Society General Meeting, 2015

The purpose of this paper is to formulate, document and present a novel optimal distribution subs... more The purpose of this paper is to formulate, document and present a novel optimal distribution substation bus design methodology considering reliability and economics. A simple test system is used to evaluate and compare four common distribution substation bus configurations. Capital, maintenance and operating costs including the costs of system losses as well as the expected customer outage costs have been considered in the formulation. A standard 115 kV/12.47 kV sample system having two alternative configurations for the high voltage side and two alternatives for the low voltage side has been used with this formulation. The results for the optimal design selections have been presented.

2013 IEEE Green Technologies Conference (GreenTech), 2013

Interconnection of the Distributed Generation (DG) at higher penetration levels to the distributi... more Interconnection of the Distributed Generation (DG) at higher penetration levels to the distribution grid is causing different problems with voltage profile of a typical distribution feeder. In this paper some of the voltage problems caused by increasing penetration of DG along with the role of the Volt-VAr controlling devices to mitigate these problems are investigated and discussed. A real distribution circuit containing a synchronous generator, a line voltage regulator, and a Static VAr Compensator (SVC) was used for computer modeling. Simulations were conducted considering full load and light load conditions, without, then with DG at various penetration levels. Simulations' results verifying the high voltage conditions and unacceptable voltage flickers due to increased penetration of DG have been presented. It was also concluded that voltage regulator with certain settings and SVC can mitigate some of these problems.

2014 IEEE PES General Meeting | Conference & Exposition, 2014

Interconnection of Photovoltaic (PV) systems as Distributed Generation (DG) sources to the distri... more Interconnection of Photovoltaic (PV) systems as Distributed Generation (DG) sources to the distribution circuits are rapidly increasing due to their benefits and low maintenance. However, massive penetration of these systems will result in issues which can impact the operation, controls, and protection of the grids. One of these issues is related to extra injection of power during daytime with high irradiation, which results in the backflow of power and system overvoltages. Current regulations do not allow photovoltaic inverters to participate in voltage or reactive power control. Hence, photovoltaic inverters are only allowed to inject active power to ensure maximum profits for investors. From the system's perspective, however, this type of operation may not result in the best practice. The goal of this paper is to show that coordinated active/reactive power control of the PV inverters can resolve the issues associated with voltage profile, while reducing the total demand of the system from the Utility's perspective. For this purpose, a nonlinear optimization problem has been defined in which total demand of the system is minimized, considering system constraints such as voltage profile and line flows. Simulations on the IEEE 34 bus test system show that the proposed practice can significantly improve the system behavior.

2006 38th North American Power Symposium, 2006

In this paper, it is shown that using the power importance. Some work already exists in the liter... more In this paper, it is shown that using the power importance. Some work already exists in the literature related injection model for a UPFC, there exists a set of operating points to the choice of optimal set of operating points for the FACTS for which the same amount of ac bus voltage and active/reactive devices in steady-state conditions. These approaches mostly series power injections can be evaluated. These various operating focus on the operation of the system from aspects such as

2017 North American Power Symposium (NAPS), 2017

To study or control the behavior of an actual equipment, such as a protection relay in a complex ... more To study or control the behavior of an actual equipment, such as a protection relay in a complex power system, real-time digital simulators can be employed in order to provide a safe and efficient environment for researchers. The goal of this paper is to investigate and verify the operation of an “actual” overcurrent protection relay in a simulated distribution system. More precisely, this work has investigated the behavior of instantaneous overcurrent protection element of the SEL-351S™ relay using OPAL-RT digital simulator through hardware-in-the-loop testing to demonstrate desensitization of the relay in protecting a distribution feeder when various levels of distributed generations exist in the system.

2019 North American Power Symposium (NAPS), 2019

Increasing awareness and worry about ecological and environmental problems and the shortage of oi... more Increasing awareness and worry about ecological and environmental problems and the shortage of oil resources are strong incentives to develop more efficient vehicles, with lower fuel consumption. Electric vehicles (EVs) usage is showing a rise in response to the proper time and conditions. Rapid growth of electrical vehicles accessing the electric grid, demands meticulously designed charging scheduling algorithms in smart grid applications [3]. Several influencing factors affect the profiles of the EV charging load, such as charging start time, daily driving distance, capacity of their battery and environmental factors.Smart charging/discharging strategies of EVs can decrease daily cost of electricity for EV owners, assist in peak load shaving in the power grid, and improve reliability of power system. This paper focuses on optimized and coordinated charging of EVs and its effects on the load profile of the system.

2017 North American Power Symposium (NAPS), 2017

In this paper, a three-level Boost (TLB) converter maximum power point tracking (MPPT) control st... more In this paper, a three-level Boost (TLB) converter maximum power point tracking (MPPT) control strategy for a two-stage photovoltaic (PV) system based on model predictive control (MPC) is proposed. This method realizes fast and precise control through establishment of a prediction model and minimization of a cost function. In the work, first a three-level predictive model for the boost converter is extracted, then a predictive control algorithm using the Perturb and Observe (P&O) method is proposed, and subsequently voltage balance of the neutral point of the converter is added to the control loop. Based on the proposed method, since the inverter is not obligated to control the DC-link neutral point voltage, its modulation can be used to realize other controls on the AC side to improve grid operation. Results of the control scheme have been verified through Matlab / Simulink, and the results have been in agreement with the expectations.

49th International Conference on Parallel Processing - ICPP : Workshops, 2020

In this study, we accelerate power flow computation used in modeling and analysis of electric pow... more In this study, we accelerate power flow computation used in modeling and analysis of electric power distribution systems utilizing the GPU. We use kernels and parallel computation patterns (i.e., segmented scan and reduction) running on the GPU to accelerate a common method that is used to perform power flow computation called “forward-backward sweep”. To evaluate our approach, we compare the GPU-accelerated parallel implementation of this method written in CUDA to the serial implementation that runs on the CPU. We perform our tests on binary power distribution trees that have number of nodes between 1K to 256K. Our results show that the parallel implementation brings up to 3.9x total speedup over the serial implementation. As expected, for the parts of the computation that entirely run on the GPU, larger speedups are achieved as the size of the distribution tree increases. We also provide a discussion on how the topology of the tree would affect the results.

2017 IEEE Power & Energy Society Innovative Smart Grid Technologies Conference (ISGT), 2017

Due to environmental impacts of traditional energy production, the integration of renewable energ... more Due to environmental impacts of traditional energy production, the integration of renewable energy in high volume has become more favorable. A series of analytical studies are required prior to integration of windfarms into the transmission system. For instance, equipment sizing and high voltage analysis are some of the crucial assessments. Equipment sizing in high voltage substation is done considering Transient Over Voltage (TOV) quantity that any device may tolerate due to experiencing surge and/or switching. The high elevation levels that windfarms are installed, make them more susceptible to TOVs related to lightning strikes. This paper focuses on sizing the required protecting devices in a windfarm interconnected to transmission system through a high voltage substation. The study methodology is suitable for fast transient analysis such as lightning analysis.

2017 IEEE Power & Energy Society Innovative Smart Grid Technologies Conference (ISGT), 2017

A modular microgrid unit (MMGU) is a packaged microgrid that can work autonomously but is also ca... more A modular microgrid unit (MMGU) is a packaged microgrid that can work autonomously but is also capable of connecting to other MMGUs to form an expandable microgrid. It is flexible and can be implemented with different resources, such as hydropower or wind. An MMGU's power electronic interface accompanied with battery storage unit provides a high level of stability, which is critical in microgrids. A key factor when implementing an MMGU is to determine appropriate MMGU component ratings to match physical characteristics of available resources. This paper discusses the application of an MMGU in a pumped-storage unit. The main components of MMGU are introduced and equations are presented to find rating of these components. Then, typical MMGU component ratings for a 250-kW system are calculated and the feasibility of the design is assessed.

2020 52nd North American Power Symposium (NAPS), 2021

This paper proposes an optimized operation scheme for a mixed-energy power plant consisting of re... more This paper proposes an optimized operation scheme for a mixed-energy power plant consisting of renewable energy resources (RES), synchronous generators (SG), and energy storage systems (ESS). While the proposed method is applicable for any type of RES, SG, and ESS, a combination of RES, gas-fired generators, and battery energy storage system (BESS) has been utilized for the sake of simulation in this paper. Assuming that the total as well as RES generation are both forecasted and available within a known period of time, the difference between the two needs to be shared among gas turbine generators and battery storage units. To ease the computational burden, several gas turbine generators are aggregated to form a bulk synchronous generation unit. Considering constraints of SG and BESS, the objective of the optimization problem is to minimize gas turbine generation over the period of a day. After the share of the bulk SG and each battery energy storage unit is found, a unit commitment study for individual gas turbine generators is performed. The results found by this approach has proven to result in less overall schedule deviation compared to when BESS units are simply charged when demand is low and discharged when demand is high (up to their maximum capacity). In addition, this method entails low computation requirements and produces solutions in a short time.

This paper introduces a novel type of direct-drive electric generator, suitable for producing hig... more This paper introduces a novel type of direct-drive electric generator, suitable for producing high-power at low rpm in wind applications. The proposed patented design eliminates the magnetic core based on the concept of circular flux and characteristics of Halbach Array. By using circular flux crossing through patented Folded Electromagnetic Coils (FECs) on the stator, an optimal design with maximum use of space will be gained. Furthermore, through special configuration of diametric and axial magnets on the rotor, a pattern of circular flux can be produced, which is magnified only on the side of the stator (where needed), based on characteristics of the Halbach array. By using such design, the need for using magnets on both sides of armature windings (devised in certain designs such as the Yokeless and Segmented Armature (YASA) topology), will be eliminated, resulting in further reduction of the magnetic materials in the machine design. In the paper, we show how the proposed design ...

2018 IEEE Electrical Power and Energy Conference (EPEC), 2018

In the bulk power system, forecasting and scheduling demand and generating resources is the initi... more In the bulk power system, forecasting and scheduling demand and generating resources is the initial step in maintaining power system frequency. To improve system frequency, controllable generating resources can provide adjustments to ensure balance between supply and demand in real-time operations. This existing process is currently being challenged with the deployment of intermittent sources such as wind and solar, which can impact total supply and demand forecasts. As a result, more flexible resources and more dynamic control schemes are clearly needed to adapt the system design to meet the disruptive renewable sources being deployed in large numbers. In this paper, the goal is to demonstrate how through minimizing schedule deviations by a unified smart generating system, the short-term primary frequency response, as well as the long-term frequency profile of a multi-area network can be significantly enhanced. This concept can potentially improve system operations through distribu...

2015 North American Power Symposium (NAPS), 2015

Applications of Battery Energy Storage Systems (BESS) in the power grids will be expanded in the ... more Applications of Battery Energy Storage Systems (BESS) in the power grids will be expanded in the coming years due to factors such as decreasing costs of such systems. In a modern power network, BESS systems can be optimally controlled for peak-load shaving and other ancillary services such as volt-var control, system balancing and loss reduction. However, all these “system-level” controls will depend on the capability of each individual BESS to independently control the active and reactive power injection/absorption at its connected bus, and to maintain the voltage of the DC link between its AC/DC and DC/DC converters. As a result, understanding the behavior and control requirements for the operation of the BESS is necessary. In this paper, an active AC/DC rectifier and a bidirectional DC/DC converter have been modeled and analyzed for charging and discharging of the batteries in a BESS system. The models used in these analyses have been developed based on an integrated state-space equation set for the converters and the battery. This type of modeling is proper for demonstration of the effects of massively integrated storage systems in the bulk power grids.

Electric Power Components and Systems, 2015

Abstract This article discusses the potential for identifying faulted segment(s) on multi-phase d... more Abstract This article discusses the potential for identifying faulted segment(s) on multi-phase distribution primaries using sequence component modeling and standard three-phase short-circuit solvers. Identifying faulted segments in a timely manner speeds up fault isolation and restoration processes, contributing to greater feeder reliability. The methodology utilizes fundamental frequency current magnitudes from the feeder head in conjunction with an approximate sequence model of the multi-phase feeder including single-phase and double-phase line segments augmented with dummy lines. Under certain fault conditions, multiple faulted segments may be yielded for which a new faulted segment reduction method based on voltage sag data is proposed. The Saskpower network simulated in MATLAB/Simulink (The MathWorks, Natick, Massachusetts, USA) environment was used to evaluate the faulted segment identification and reduction methods. The evaluation studies show quite promising results in uniquely identifying the actual faulted segment with reduced measurement and modeling requirements.

La presente invention se rapporte a une protection contre une instabilite de la tension d'un ... more La presente invention se rapporte a une protection contre une instabilite de la tension d'un systeme d'alimentation electrique qui est mise en œuvre par determination d'un changement de la puissance injectee dans une region digne d'interet dans le systeme d'alimentation electrique sur la base des mesures de puissance synchronisees realisees a partir de differents points d'injection de puissance de la region digne d'interet (200) et par determination d'un changement de la puissance absorbee par une ou plusieurs charges dans la region digne d'interet sur la base des mesures de puissance synchronisees realisees a partir de differents points de charge de la region digne d'interet (210). Un changement de la perte de puissance de la region digne d'interet est determine sur la base de la difference entre le changement de la puissance injectee dans la region digne d'interet et le changement de la puissance absorbee par la region digne d'in...

2016 North American Power Symposium (NAPS), 2016

This paper focuses on the application of BESS (Battery Energy Storage Systems) in improved operat... more This paper focuses on the application of BESS (Battery Energy Storage Systems) in improved operation of distribution grids that are highly penetrated with PV (Photovoltaic) systems. The paper features a state-space based model for BESS and implements a simple and effective approach for peak load shaving by considering device constraints. The grid-connected PV+BESS system proposed in this work contains bidirectional DC/DC and AC/DC converters and batteries, and is capable of simultaneous control of active power, reactive power, and DC-link voltage. In this work, an energy management strategy with the goal of peak-shaving has been proposed, which also considers degradation and ageing limits of the batteries. Simulations have been performed at different battery capacity cases to show the capabilities of the proposed PV+BESS.

2015 IEEE Power & Energy Society General Meeting, 2015

Increased penetration levels of Distributed Generation (DG) can cause steady state and transient ... more Increased penetration levels of Distributed Generation (DG) can cause steady state and transient voltage issues and possible overloading conditions. This paper aims to verify the overvoltage and overloading issues caused by DG at high penetration levels. A typical utility distribution feeder was selected using cluster analysis for simulations. DG at various penetration levels was interconnected at 4 different locations on the feeder. Summer Peak (SP), Partial Peak (PP) and Winter Peak (WP) loading conditions have been studied. Solar Photo-Voltaic (PV) is used as DG for all simulations. Static VAr Compensators (SVC) and Smart Inverters (SI) and their mitigating effects have been reported as possible solutions. Acceptable DG penetration levels have been proposed depending on DG locations and associated voltage or overloading issues. Two special cases, one involving simultaneous high and low voltage conditions and the other related to high voltages at multiple locations have also been studied and reported.

2015 IEEE Power & Energy Society General Meeting, 2015

The purpose of this paper is to formulate, document and present a novel optimal distribution subs... more The purpose of this paper is to formulate, document and present a novel optimal distribution substation bus design methodology considering reliability and economics. A simple test system is used to evaluate and compare four common distribution substation bus configurations. Capital, maintenance and operating costs including the costs of system losses as well as the expected customer outage costs have been considered in the formulation. A standard 115 kV/12.47 kV sample system having two alternative configurations for the high voltage side and two alternatives for the low voltage side has been used with this formulation. The results for the optimal design selections have been presented.

2013 IEEE Green Technologies Conference (GreenTech), 2013

Interconnection of the Distributed Generation (DG) at higher penetration levels to the distributi... more Interconnection of the Distributed Generation (DG) at higher penetration levels to the distribution grid is causing different problems with voltage profile of a typical distribution feeder. In this paper some of the voltage problems caused by increasing penetration of DG along with the role of the Volt-VAr controlling devices to mitigate these problems are investigated and discussed. A real distribution circuit containing a synchronous generator, a line voltage regulator, and a Static VAr Compensator (SVC) was used for computer modeling. Simulations were conducted considering full load and light load conditions, without, then with DG at various penetration levels. Simulations' results verifying the high voltage conditions and unacceptable voltage flickers due to increased penetration of DG have been presented. It was also concluded that voltage regulator with certain settings and SVC can mitigate some of these problems.

2014 IEEE PES General Meeting | Conference & Exposition, 2014

Interconnection of Photovoltaic (PV) systems as Distributed Generation (DG) sources to the distri... more Interconnection of Photovoltaic (PV) systems as Distributed Generation (DG) sources to the distribution circuits are rapidly increasing due to their benefits and low maintenance. However, massive penetration of these systems will result in issues which can impact the operation, controls, and protection of the grids. One of these issues is related to extra injection of power during daytime with high irradiation, which results in the backflow of power and system overvoltages. Current regulations do not allow photovoltaic inverters to participate in voltage or reactive power control. Hence, photovoltaic inverters are only allowed to inject active power to ensure maximum profits for investors. From the system's perspective, however, this type of operation may not result in the best practice. The goal of this paper is to show that coordinated active/reactive power control of the PV inverters can resolve the issues associated with voltage profile, while reducing the total demand of the system from the Utility's perspective. For this purpose, a nonlinear optimization problem has been defined in which total demand of the system is minimized, considering system constraints such as voltage profile and line flows. Simulations on the IEEE 34 bus test system show that the proposed practice can significantly improve the system behavior.

2006 38th North American Power Symposium, 2006

In this paper, it is shown that using the power importance. Some work already exists in the liter... more In this paper, it is shown that using the power importance. Some work already exists in the literature related injection model for a UPFC, there exists a set of operating points to the choice of optimal set of operating points for the FACTS for which the same amount of ac bus voltage and active/reactive devices in steady-state conditions. These approaches mostly series power injections can be evaluated. These various operating focus on the operation of the system from aspects such as

2017 North American Power Symposium (NAPS), 2017

To study or control the behavior of an actual equipment, such as a protection relay in a complex ... more To study or control the behavior of an actual equipment, such as a protection relay in a complex power system, real-time digital simulators can be employed in order to provide a safe and efficient environment for researchers. The goal of this paper is to investigate and verify the operation of an “actual” overcurrent protection relay in a simulated distribution system. More precisely, this work has investigated the behavior of instantaneous overcurrent protection element of the SEL-351S™ relay using OPAL-RT digital simulator through hardware-in-the-loop testing to demonstrate desensitization of the relay in protecting a distribution feeder when various levels of distributed generations exist in the system.

2019 North American Power Symposium (NAPS), 2019

Increasing awareness and worry about ecological and environmental problems and the shortage of oi... more Increasing awareness and worry about ecological and environmental problems and the shortage of oil resources are strong incentives to develop more efficient vehicles, with lower fuel consumption. Electric vehicles (EVs) usage is showing a rise in response to the proper time and conditions. Rapid growth of electrical vehicles accessing the electric grid, demands meticulously designed charging scheduling algorithms in smart grid applications [3]. Several influencing factors affect the profiles of the EV charging load, such as charging start time, daily driving distance, capacity of their battery and environmental factors.Smart charging/discharging strategies of EVs can decrease daily cost of electricity for EV owners, assist in peak load shaving in the power grid, and improve reliability of power system. This paper focuses on optimized and coordinated charging of EVs and its effects on the load profile of the system.

2017 North American Power Symposium (NAPS), 2017

In this paper, a three-level Boost (TLB) converter maximum power point tracking (MPPT) control st... more In this paper, a three-level Boost (TLB) converter maximum power point tracking (MPPT) control strategy for a two-stage photovoltaic (PV) system based on model predictive control (MPC) is proposed. This method realizes fast and precise control through establishment of a prediction model and minimization of a cost function. In the work, first a three-level predictive model for the boost converter is extracted, then a predictive control algorithm using the Perturb and Observe (P&O) method is proposed, and subsequently voltage balance of the neutral point of the converter is added to the control loop. Based on the proposed method, since the inverter is not obligated to control the DC-link neutral point voltage, its modulation can be used to realize other controls on the AC side to improve grid operation. Results of the control scheme have been verified through Matlab / Simulink, and the results have been in agreement with the expectations.

49th International Conference on Parallel Processing - ICPP : Workshops, 2020

In this study, we accelerate power flow computation used in modeling and analysis of electric pow... more In this study, we accelerate power flow computation used in modeling and analysis of electric power distribution systems utilizing the GPU. We use kernels and parallel computation patterns (i.e., segmented scan and reduction) running on the GPU to accelerate a common method that is used to perform power flow computation called “forward-backward sweep”. To evaluate our approach, we compare the GPU-accelerated parallel implementation of this method written in CUDA to the serial implementation that runs on the CPU. We perform our tests on binary power distribution trees that have number of nodes between 1K to 256K. Our results show that the parallel implementation brings up to 3.9x total speedup over the serial implementation. As expected, for the parts of the computation that entirely run on the GPU, larger speedups are achieved as the size of the distribution tree increases. We also provide a discussion on how the topology of the tree would affect the results.

2017 IEEE Power & Energy Society Innovative Smart Grid Technologies Conference (ISGT), 2017

Due to environmental impacts of traditional energy production, the integration of renewable energ... more Due to environmental impacts of traditional energy production, the integration of renewable energy in high volume has become more favorable. A series of analytical studies are required prior to integration of windfarms into the transmission system. For instance, equipment sizing and high voltage analysis are some of the crucial assessments. Equipment sizing in high voltage substation is done considering Transient Over Voltage (TOV) quantity that any device may tolerate due to experiencing surge and/or switching. The high elevation levels that windfarms are installed, make them more susceptible to TOVs related to lightning strikes. This paper focuses on sizing the required protecting devices in a windfarm interconnected to transmission system through a high voltage substation. The study methodology is suitable for fast transient analysis such as lightning analysis.

2017 IEEE Power & Energy Society Innovative Smart Grid Technologies Conference (ISGT), 2017

A modular microgrid unit (MMGU) is a packaged microgrid that can work autonomously but is also ca... more A modular microgrid unit (MMGU) is a packaged microgrid that can work autonomously but is also capable of connecting to other MMGUs to form an expandable microgrid. It is flexible and can be implemented with different resources, such as hydropower or wind. An MMGU's power electronic interface accompanied with battery storage unit provides a high level of stability, which is critical in microgrids. A key factor when implementing an MMGU is to determine appropriate MMGU component ratings to match physical characteristics of available resources. This paper discusses the application of an MMGU in a pumped-storage unit. The main components of MMGU are introduced and equations are presented to find rating of these components. Then, typical MMGU component ratings for a 250-kW system are calculated and the feasibility of the design is assessed.

2020 52nd North American Power Symposium (NAPS), 2021

This paper proposes an optimized operation scheme for a mixed-energy power plant consisting of re... more This paper proposes an optimized operation scheme for a mixed-energy power plant consisting of renewable energy resources (RES), synchronous generators (SG), and energy storage systems (ESS). While the proposed method is applicable for any type of RES, SG, and ESS, a combination of RES, gas-fired generators, and battery energy storage system (BESS) has been utilized for the sake of simulation in this paper. Assuming that the total as well as RES generation are both forecasted and available within a known period of time, the difference between the two needs to be shared among gas turbine generators and battery storage units. To ease the computational burden, several gas turbine generators are aggregated to form a bulk synchronous generation unit. Considering constraints of SG and BESS, the objective of the optimization problem is to minimize gas turbine generation over the period of a day. After the share of the bulk SG and each battery energy storage unit is found, a unit commitment study for individual gas turbine generators is performed. The results found by this approach has proven to result in less overall schedule deviation compared to when BESS units are simply charged when demand is low and discharged when demand is high (up to their maximum capacity). In addition, this method entails low computation requirements and produces solutions in a short time.

This paper introduces a novel type of direct-drive electric generator, suitable for producing hig... more This paper introduces a novel type of direct-drive electric generator, suitable for producing high-power at low rpm in wind applications. The proposed patented design eliminates the magnetic core based on the concept of circular flux and characteristics of Halbach Array. By using circular flux crossing through patented Folded Electromagnetic Coils (FECs) on the stator, an optimal design with maximum use of space will be gained. Furthermore, through special configuration of diametric and axial magnets on the rotor, a pattern of circular flux can be produced, which is magnified only on the side of the stator (where needed), based on characteristics of the Halbach array. By using such design, the need for using magnets on both sides of armature windings (devised in certain designs such as the Yokeless and Segmented Armature (YASA) topology), will be eliminated, resulting in further reduction of the magnetic materials in the machine design. In the paper, we show how the proposed design ...

2018 IEEE Electrical Power and Energy Conference (EPEC), 2018

In the bulk power system, forecasting and scheduling demand and generating resources is the initi... more In the bulk power system, forecasting and scheduling demand and generating resources is the initial step in maintaining power system frequency. To improve system frequency, controllable generating resources can provide adjustments to ensure balance between supply and demand in real-time operations. This existing process is currently being challenged with the deployment of intermittent sources such as wind and solar, which can impact total supply and demand forecasts. As a result, more flexible resources and more dynamic control schemes are clearly needed to adapt the system design to meet the disruptive renewable sources being deployed in large numbers. In this paper, the goal is to demonstrate how through minimizing schedule deviations by a unified smart generating system, the short-term primary frequency response, as well as the long-term frequency profile of a multi-area network can be significantly enhanced. This concept can potentially improve system operations through distribu...

2015 North American Power Symposium (NAPS), 2015

Applications of Battery Energy Storage Systems (BESS) in the power grids will be expanded in the ... more Applications of Battery Energy Storage Systems (BESS) in the power grids will be expanded in the coming years due to factors such as decreasing costs of such systems. In a modern power network, BESS systems can be optimally controlled for peak-load shaving and other ancillary services such as volt-var control, system balancing and loss reduction. However, all these “system-level” controls will depend on the capability of each individual BESS to independently control the active and reactive power injection/absorption at its connected bus, and to maintain the voltage of the DC link between its AC/DC and DC/DC converters. As a result, understanding the behavior and control requirements for the operation of the BESS is necessary. In this paper, an active AC/DC rectifier and a bidirectional DC/DC converter have been modeled and analyzed for charging and discharging of the batteries in a BESS system. The models used in these analyses have been developed based on an integrated state-space equation set for the converters and the battery. This type of modeling is proper for demonstration of the effects of massively integrated storage systems in the bulk power grids.

Electric Power Components and Systems, 2015

Abstract This article discusses the potential for identifying faulted segment(s) on multi-phase d... more Abstract This article discusses the potential for identifying faulted segment(s) on multi-phase distribution primaries using sequence component modeling and standard three-phase short-circuit solvers. Identifying faulted segments in a timely manner speeds up fault isolation and restoration processes, contributing to greater feeder reliability. The methodology utilizes fundamental frequency current magnitudes from the feeder head in conjunction with an approximate sequence model of the multi-phase feeder including single-phase and double-phase line segments augmented with dummy lines. Under certain fault conditions, multiple faulted segments may be yielded for which a new faulted segment reduction method based on voltage sag data is proposed. The Saskpower network simulated in MATLAB/Simulink (The MathWorks, Natick, Massachusetts, USA) environment was used to evaluate the faulted segment identification and reduction methods. The evaluation studies show quite promising results in uniquely identifying the actual faulted segment with reduced measurement and modeling requirements.