Engineering Commons^™

A Novel Two-Stage Ac-Dc Power Converter With Partial Power Processing, Mina Fakhri

Electronic Thesis and Dissertation Repository

A two-stage power converter with an AC-DC boost converter and a soft-switched DC-DC full-bridge converter is proposed in this thesis. The first stage has two interleaved modules that perform power factor correction; the second stage converts the output of the first stage to the desired output. An auxiliary circuit with a switch, a small transformer, and passive components is used to turn off the AC-DC converter switches with soft-switching; the auxiliary switch can also be turned on and off softly. The secondary of the auxiliary transformer is connected to the output of the overall converter so that some power can …

A Novel Passive Islanding Detection Method Based On Phase-Locked Loop, Hoda Zamani

Electronic Thesis and Dissertation Repository

The ever-increasing penetration of distributed energy resources in power distribution systems has led to challenges in the detection of islanding. Among different islanding detection methods (IDMs), passive methods are the least intrusive and typically require the lowest investment cost. However, they generally suffer from larger non-detection zones (NDZs) and higher nuisance detection ratios as compared to active, hybrid, and remote IDMs. This study provides an overview of the criteria outlined in the existing technical literature for the performance evaluation of IDMs, a review and comparison of the existing passive IDMs, and an analysis of the phase-locked loop (PLL) behaviour under …

Numerical Investigations Of The Fluid Flow And Heat Transfer And Construction Of Control System For The Canadian Supercritical Water-Cooled Reactor Power Plant, Huirui Han

Electronic Thesis and Dissertation Repository

Canada participated in the Generation IV nuclear reactors with the Supercritical Water-Cooled Reactor (SCWR) concept. This work focuses on the numerical studies of the fluid flow and heat transfer of the supercritical water in the nuclear reactor fuel bundle, and the construction of the linear dynamic model and the design of the control system for the Canadian SCWR power plant.

Firstly, the fluid flow and heat transfer of the supercritical water in the vertical tube and the rod bundle is numerically investigated to evaluate whether the existing turbulent models could successfully caption the wall temperature variations at supercritical conditions by …

Configuration And Sizing Of Small Modular Reactor With Thermal Energy Storage Within A Microgrid For Off-Grid Communities, Michael W. C. Davis

Electronic Thesis and Dissertation Repository

Many off-grid communities in Canada rely on diesel generators for their electricity needs. This is not only expensive but also produces significant greenhouse gas emissions. Small modular reactors (SMRs) have been proposed to replace diesel generators and can be combined with photovoltaic (PV) sources to form a microgrid. However, fluctuations in loads and PV create challenges for SMRs. Integrating a thermal energy storage (TES) system with the SMR can increase the flexibility of the power system to operate more effectively. This thesis first examines methodologies to determine suitable configurations of such a microgrid. Through analysis of the system components and …

Deep Learning For Load Forecasting With Smart Meter Data: Online And Federated Learning, Mohammad Navid Fekri

Electronic Thesis and Dissertation Repository

Electricity load forecasting has been attracting increasing attention because of its importance for energy management, infrastructure planning, and budgeting. In recent years, the proliferation of smart meters has created new opportunities for forecasting on the building and even individual household levels. Machine learning (ML) has achieved great successes in this domain; however, conventional ML techniques require data transfer to a centralized location for model training, therefore, increasing network traffic and exposing data to privacy and security risks. Also, traditional approaches employ offline learning, which means that they are only trained once and miss out on the possibility to learn from …

Multi-Device Data Analysis For Fault Localization In Electrical Distribution Grids, Jacob D L Hunte

Electronic Thesis and Dissertation Repository

The work presented in this dissertation represents work which addresses some of the main challenges of fault localization methods in electrical distribution grids. The methods developed largely assume access to sophisticated data sources that may not be available and that any data sets recorded by devices are synchronized. These issues have created a barrier to the adoption of many solutions by industry. The goal of the research presented in this dissertation is to address these challenges through the development of three elements. These elements are a synchronization protocol, a fault localization technique, and a sensor placement algorithm.

The synchronization protocol …

Novel Zcs Pwm Methods For Industrial Applications, Ramtin Rasoulinezhad

Electronic Thesis and Dissertation Repository

Pulse width modulation (PWM) converters that consist of two or more interleaved boost/buck converter modules are used widely in industry. Soft-switching approaches for these converters can either be zero-voltage switching (ZVS) if implemented with MOSFETs or zero-current switching (ZCS) if implemented with IGBTs. The main idea of this thesis is to implement ZCS for IGBT turn-on and turn-off. Most converters use an auxiliary circuit that is activated whenever a main converter switch is about to be turned off, gradually diverting current away from the switch so that it can turn off with ZCS.

ZCS-PWM converters that use an auxiliary circuit …

Generative Learning In Smart Grid, Samer M. El Kababji

Electronic Thesis and Dissertation Repository

If a smart grid is to be described in one word, that word would be ’connectivity’. While electricity production and consumption still depend on a limited number of physical connections, exchanging data is growing enormously. Customers, utilities, sensors, and markets are all different sources of data that are exchanged in a ubiquitous digital setup. To deal with data complexity, many researchers recently focused on machine learning (ML) applications in smart grids. Much of the success in ML is attributed to discriminative learning where models define boundaries to categorize data. Generative learning, however, reveals how data is generated by learning the …

Deep Learning For High-Impedance Fault Detection And Classification, Khushwant Rai

Electronic Thesis and Dissertation Repository

High-Impedance Faults (HIFs) are a hazard to public safety but are difficult to detect because of their low current amplitude and diverse characteristics. Supervised machine learning techniques have shown great success in HIF detection; however, these approaches rely on resource-intensive signal processing techniques and fail in presence of non-HIF disturbances and even for scenarios not included in training data. This thesis leverages unsupervised learning and proposes a Convolutional Autoencoder framework for HIF Detection (CAE-HIFD). In CAE-HIFD, Convolutional Autoencoder learns only from HIF signals by employing cross-correlation; consequently, eliminating the need for diverse non-HIF scenarios in training. Furthermore, this thesis proposes …

Power Management And Control To Balance Residential Microgrids With Individual Phase-Wise Generation And Storage, Syed Ahmed Raza Naqvi

Electronic Thesis and Dissertation Repository

The past decade has seen a significant rise in proliferation of roof-top photovoltaic (PV) systems with storage units at residential sites. This has affected the way power system engineers and researchers have previously studied distribution systems as passive networks. With the introduction of these local distributed energy resources, a distribution system has become part of an active network. This modernization of the power distribution network, brings along with itself a number of key issues that need to be pro-actively tackled by the local utilities.

In North America, with family-owned roof-top PV systems, storage devices and electric vehicles, the concept of …

An Investigation Of The Interleaved Operation Of A Stacked Ac-Dc Single-Stage Flyback Converter, Mengkai Xiong

Electronic Thesis and Dissertation Repository

Low power AC-DC power conversion is typically done with a two-stage converter that consists of an AC-DC front-end boost converter that also performs input power factor correction and an isolated DC-DC back-end converter that is either a flyback or a forward converter. In applications where cost is an overriding factor, single-stage AC-DC converters that use a single power converter to simultaneously perform input power factor correction and AC-DC conversion can be used. In applications where output filtering and hold-up time are important considerations, single-stage AC-DC converters are implemented with a DC bus capacitor.

The main objective of this thesis is …

Synchrophasor Based Islanding & Open Phase Fault Protection In Distribution Systems, Mansour Jalali

Electronic Thesis and Dissertation Repository

With the rapid growth of renewable energy resources, energy efficiency initiatives, electric vehicles, energy storage, etc., distribution systems are becoming more complex such that conventional protection, control, and measurement infrastructure – typically concentrated at the main substation, with little to no access to information along the feeder – cannot maintain the reliability of the system without some sort of additional protection, control and measurement functionalities. As an example, a dedicated communication channel for carrying the transfer trip signal from the substation to the Point of Common Coupling (PCC) to prevent islanding operation of alternative resources, has been a requirement for …

Novel Control Of Pv Solar Farms As Statcom (Pv-Statcom) For Frequency Control And Power Oscillation Damping, Mohammad Akbari Kelishadi

Electronic Thesis and Dissertation Repository

Frequency stability and low-frequency power oscillations are two major concerns in modern power systems. PV-STATCOM is a patented concept which enables PV inverters to provide STATCOM functions, during day and night, as well as real power modulation during daytime. This thesis aims to utilize PV-STATCOM capability effectively for enhancing frequency stability and power oscillations damping.

A novel, simultaneous real power-based Fast Frequency Response (FFR) and reactive power-based Power Oscillation Damping (POD) control is proposed for PV-STATCOMs. This control not only significantly reduces system under- and over-frequency deviations, but also uses the unutilized capacity of PV inverters to enhance damping of …

Split Dc Bus Converters For Power Electronic And Ac-Dc Microgrid Applications, Javad Khodabakhsh

Electronic Thesis and Dissertation Repository

Power electronic converters are used extensively for electrical power conversion in applications such as renewable energy systems, utility applications, and electric vehicles. Such converters are needed as it is rare for a source voltage to fit the needs of a load or a set of loads for any particular application. They consist of active semiconductor switches and passive components that are combined in circuit structures (topologies) that are operated with a control strategy. The focus of this thesis is on AC-DC and DC-DC converters and their applications in AC-DC microgrids.

AC-DC converters are typically two-stage converters that consist of a …

Novel Night And Day Control Of Pv Solar Farm As Statcom (Pv-Statcom) For Critical Induction Motor Stabilization And Fidvr Alleviation, Sibin Mohan

Electronic Thesis and Dissertation Repository

Induction motors are globally used in several critical operations such as petrochemicals, mining, process control, etc., where their shutdown during faults causes significant financial loss. System faults can also lead to Fault Induced Delayed Voltage Recovery (FIDVR) causing service disruptions. Dynamic reactive power compensators such as SVC and STATCOM are conventionally employed to mitigate these issues, however, these are very expensive.

PV solar plants are growing at unprecedented rate globally and are likely to be installed near such critical motors. This thesis presents several novel applications of a patented technology of utilizing PV solar plants, both during night and day, …

Novel Pv Solar Farm Control As Statcom (Pv-Statcom) For Ssr Mitigation In Synchronous Generators And Wind Farms, Reza Salehi Sharafdarkolaee

Electronic Thesis and Dissertation Repository

Transmission lines across the world are extensively compensated by series capacitors to increase their power transfer capacity. However, series compensation can potentially cause subsynchronous resonance (SSR) which can lead to significant damage in shafts of synchronous generators and wind farms. Dynamic reactive power compensators such as STATCOM and SVCs are typically used for mitigation of SSR, but these are quite expensive.

Large scale PV solar farms are growing at a very rapid rate across the world. It is quite likely that they may get installed near synchronous generators or wind farms which are directly or indirectly interfaced with series compensated …

Integrity Protection Of The Dc Microgrid, Jafar Mohammadi

Electronic Thesis and Dissertation Repository

The direct current (DC) microgrid has attracted great attention in the recent years due to its significant advantages over the alternating current (AC) microgrid. These advantages include elimination of unnecessary AC/DC power converters, lower investment cost, lower losses, higher reliability, and resilience to utility-side disturbances. A practical DC microgrid requires an effective control strategy to regulate the DC bus voltages, enable power sharing between the distributed energy resources (DERs), and provide acceptable dynamic response to disturbances. Furthermore, when the power demand of the loads is higher than the power generation of the DERs in the DC microgrid, the power balance …

Optimal Decentralized Coordination Of Sources In Islanded And Grid-Connected Microgrids, Mithun Mallick

Electronic Thesis and Dissertation Repository

Rising climate change concerns in recent years have instigated the emergence of sustainable sources to reduce dependence on high-emission, isolated bulk generation systems. The microgrid framework relies on integrating these distributed energy resources (DERs) to achieve regional energy independence that leads to a reliable and environment-friendly power grid. In this work, highly granular and decentralized coordination schemes are proposed that will enable fast computation of source dispatch set-points, thereby appropriately accounting for frequent changes in regional load-supply configuration of a microgrid. The mathematical models utilized in the study sufficiently represent the steady-state electrical interdependencies and feasibility limits in islanded or …

Continuous Monitoring Of Neutral Grounding Resistors And Reactors, Rahim Jafari

Electronic Thesis and Dissertation Repository

Electrical power system components are designed three-phase balanced and symmetric with the internal connection of wye or delta. The common point of the wye-connected equipment, which is called neutral, is impedance grounded for many reasons such as fault ride through by controlling transient overvoltages, and limiting the ground overcurrents. Depending on the application, different neutral impedance grounding methods exist that employ resistors or reactors with/without neutral grounding transformers. These apparatuses are known as Neutral Grounding Devices (NGD). The most well-known sort of NGDsarethe Neutral Grounding Resistor (NGR) and Neutral Grounding Reactor (NGL) which are the main focus of this research …

Spectral And Energy Efficient Communication Systems And Networks, Abdulbaset Hamed

Electronic Thesis and Dissertation Repository

In this thesis, design and analysis of energy- and spectral-efficient communication and cellular systems in micro wave and millimeter wave bands are considered using the following system performance metrics: i) Energy efficiency; ii) Spectral efficiency; iii) Spatial spectral efficiency; iv) Spatial energy efficiency, and v) Bit error rate. Statistical channel distributions, Nakagami-m and Generalized-K, and path loss models, Line of Sight (LOS) and Non-Line of Sight (NLOS), are used to represent the propagation environment in these systems. Adaptive M-QAM and M-CPFSK communication systems are proposed to enhance their efficiency metrics as a function of Signal-to-Noise Ratio (SNR) over the channel. …

Non-Pilot Protection Of The Inverter-Dominated Ac Microgrid, Houman Lahiji

Electronic Thesis and Dissertation Repository

The main objective of this research is to develop reliable non-pilot protection and control strategies for the inverter-dominated microgrid. First, an improved Proportional-Derivative (PD) droop control strategy is proposed for enhanced disturbance response of the inverter-dominated AC microgrid. The proposed strategy significantly improves microgrid dynamic response and stability without requiring communication between distributed energy resources. Moreover, the impacts of large startup currents of induction motors on the stability and power quality of the inverter-dominated microgrid are investigates and recommendations for minimizing the associated adverse effects are made.

Subsequently, a fast, selective, and reliable protection strategy for the inverter-dominated microgrid is …

New Algorithms For Locating Faults In Series Capacitive Compensated Transmission Lines, Tirath Bains

Electronic Thesis and Dissertation Repository

The precise location of the fault in a series capacitive compensated transmission line (SCCTL) plays an integral part in limiting the maintenance time following its tripping due to the occurrence of a permanent fault. Since, an SCCTL acts as a huge corridor of power, its outage will result in huge monetary losses which are directly proportion to the time it remains out of service. In worst case scenario, the tripping of an SCCTL might lead to the cascaded tripping of the parallel transmission lines due to overloading. Therefore, the need for an accurate and robust fault location algorithm for the …

Transformerless High-Power Medium-Voltage Multi-Module Pv Converters, Hasan Bayat

Electronic Thesis and Dissertation Repository

This thesis is focused on the modular multilevel converter (MMC) for Photovoltaic (PV) applications. It is an attempt to address the issues associated with the modeling, control, and power mismatch elimination of the MMC-based PV systems. Firstly, a new real power reference generation scheme is proposed that creates a linear relationship between the real power reference of the system and the dc link voltage of the submodules. Further, a new power mismatch elimination strategy is proposed for the MMC-based PV system which ensures balanced currents are delivered to the host grid regardless of leg and arm power mismatches. The thesis …

A High Gain Dc-Dc Full-Bridge Converter, Prashanth Prabhu

Electronic Thesis and Dissertation Repository

High gain DC-DC converters have become increasingly popular in recent years as there is greater need to interface low voltage DC sources such as solar cells and batteries with much higher voltage DC buses. A new high gain DC-DC converter with high gain, galvanic isolation and an integrated passive snubber network is proposed in the thesis. In the thesis, the general operation of the converter is discussed, its modes of operation are explained and its features are reviewed. The design of the converter is then discussed and a set of general guidelines that can be used in the design are …

A New Single-Phase Single-Stage Ac-Dc Stacked Flyback Converter With Active Clamp Zvs, Yuntong Li

Electronic Thesis and Dissertation Repository

Single-stage AC-DC converters integrate an AC-DC front-end converter with a DC-DC back-end converter. Compared with conventional two-stage AC-DC converters, single-stage AC-DC converters use less components and only one controller, which is used to regulate the output voltage. As a result, the cost, size and complexity of AC-DC converters can be reduced, but single-stage converters do not perform as well as two-stage converters, and most have drawbacks that are related to the fact that the DC bus voltage is not controlled an can become excessive.

A new single-phase single-stage AC-DC converter that uses stacked flyback converters is proposed in this thesis. …

A Novel Ac-Dc Interleaved Zcs-Pwm Boost Converter, Ramtin Rasoulinezhad

Electronic Thesis and Dissertation Repository

AC-DC converters with input power factor correction (PFC) that consist of two or more interleaved boost converter modules are popular in industry. PFC is a must in today’s AC-DC converters as their input current must meet harmonic standards set by regulatory agencies. With interleaving, the input current of each module can make to be discontinuous and the size of their input inductors since interleaving can reduce the high ripple in each module and produce a net input current with a ripple that is comparable to that achieved with a single boost converter module with a large input inductor.

In high- …

A Comparison Between Different Snubbers For Flyback Converters, Adel Alganidi

Electronic Thesis and Dissertation Repository

The DC-DC flyback power converter is widely used in low power commercial and industrial applications ( > 150 W) such as in computers, telecom, consumer electronics because it is one of the simplest and least expensive converter topologies with transformer isolation. Its main power circuit consists of just a semiconductor device like a MOSFET operating as a switch, a transformer, an output diode and an output filter capacitor. The converter switch, however, is susceptible to high voltage spikes due to the interaction between its output capacitance and the leakage inductance of the transformer. These spikes can exceed the ratings of the …

Novel Night And Day Control Of A Pv Solar System As A Statcom (Pv-Statcom) For Damping Of Power Oscillations, Hesamaldin Maleki

Electronic Thesis and Dissertation Repository

Installations of large scale PV solar farms are rapidly increasing, worldwide. This is causing a growing apprehension that inertialess power injections from these inverter based generators will result in a decline in power system stability. Instead, this thesis presents novel applications of a patent pending technology whereby the PV solar farms actually help significantly increase system stability. A novel 24/7 (night and day) control of a large-scale PV solar farm as a dynamic reactive power compensator STATCOM, termed PV-STATCOM, is presented for damping low-frequency electromechanical power oscillations resulting in a significant improvement in power transfer capability of existing power transmission …

Fault Location In High Voltage Shunt Capacitor Banks, Hessamoddin Jouybari Moghaddam

Electronic Thesis and Dissertation Repository

High Voltage Shunt Capacitor Banks (HV-SCBs) are critical substation assets that are primarily used to improve power factor and thus power transmission capability. Over temperature, over voltages, manufacturing defects can cause internal failures of capacitor elements. With today’s sensitive protection available in numerical relays these failures will be detected and SCBs will be taken out of service. But determining the phase and section in which capacitor elements have failed is important for utilities to decrease downtime of SCBs. This thesis proposes methods to address the challenges in fault location of SCBs. The proposed methods apply calibrating factors that compensate for …

Predictive Energy Management Of Islanded Microgrids With Photovoltaics And Energy Storage, Dennis G. Michaelson

Electronic Thesis and Dissertation Repository

Islanded microgrids powered primarily by photovoltaic (PV) arrays present a challenging control problem due to the intermittent production and the relatively close scale between the sources and the loads. Energy storage in such microgrids plays an important role in balancing supply with demand, and in extending operation during periods when the PV supply is not available or insufficient. The efficient operation of such microgrids requires effective management of all resources. A predictive energy management strategy can potentially avoid or effectively mitigate upcoming outages. This thesis presents an energy management system (EMS) for such microgrids. The EMS uses a predictive approach …