Electrical and Electronics Commons^™

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 …

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 …

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 …

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 …

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 …

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 …

Analysis And Mitigation Of Temporary Over-Voltage (Tov) Phenomenon In Unintentionally Islanded Grid-Connected Photovoltaic (Pv) Inverters, Md Maruful Islam

Electronic Thesis and Dissertation Repository

Grid-connected photovoltaic (PV) solar systems, like other inverter-based distributed generators, can cause temporary over-voltages (TOVs), especially subsequent to faults and unintentional islanding incidents, and can damage equipment and customers within the host distribution network. Thus, this thesis aims to study the phenomenon and propose corrective measures for it. Thus, the thesis first presents detailed models for a conventional single-stage PV system and a modified single-stage PV system. The conventional system uses a Δ/YG isolation transformer, whereas the modified system, proposed in the literature, assumes a Y/YG isolation transformer that is effectively grounded by an additional half-bridge leg energized by the …

Sensorless Rotor Position Estimation For Brushless Dc Motors, Iram G. Raza

Electronic Thesis and Dissertation Repository

Brushless DC motor speed is controlled by synchronizing the stator coil current with rotor position in order to acquire an accurate alignment of stator rotating field with rotor permanent-magnet field for efficient transfer of energy. In order to accomplish this goal, a motor shaft is instantly tracked by using rotating rotor position sensors such as Hall effect sensors, optical encoders or resolvers etc. Adding sensors to detect rotor position affects the overall reliability and mechanical robustness of the system. Therefore, a whole new trend of replacing position sensors with sensorless rotor position estimation techniques have a promising demand.

Among the …

Secondary Electrohydrodynamic Flow Generated By Corona And Dielectric Barrier Discharges, Mohammadreza Ghazanchaei

Electronic Thesis and Dissertation Repository

One of the main goals of applied electrostatics engineering is to discover new perspectives in a wide range of research areas. Controlling the fluid media through electrostatic forces has brought new important scientific and industrial applications. Electric field induced flows, or electrohydrodynamics (EHD), have shown promise in the field of fluid dynamics. Although numerous EHD applications have been explored and extensively studied so far, most of the works are either experimental studies, which are not capable to explain the in depth physics of the phenomena, or detailed analytical studies, which are not time effective. The focus of this study is …

Smart Pv Inverter Control For Distribution Systems, Ehsan M. Siavashi

Electronic Thesis and Dissertation Repository

PV solar systems employ inverters to transform dc power from solar panels into ac power for injecting into the power grids. Inverters that perform multiple functions in addition to real power production are known as “smart inverters”.

This thesis presents a novel control of PV inverter as a dynamic reactive power compensator – STATCOM. This “smart PV inverter” control enables a PV solar inverter to operate in three modes – i) Full PV, ii) Partial STATCOM, and iii) Full STATCOM, depending upon system needs. The novel control is developed and demonstrated for the objectives of a) symmetrical voltage regulation, b) …

Three-Phase Reduced Switch Topologies For Ac-Dc Front-End And Single-Stage Converters, Dunisha Wijeratne

Electronic Thesis and Dissertation Repository

Conventional three-phase ac-dc converters have two converter stages. They have a front-end converter that converts the input ac voltage into an intermediate dc bus voltage and a second, back-end converter that converts this dc bus voltage into the desired isolated dc output voltage. The front-end converter also performs power factor correction (PFC) and shapes the three-phase input currents so that they are nearly sinusoidal and in phase with the three-phase input voltages. This allows the ac power source to be used in the most efficient manner.

The front-end ac-dc converter is typically implemented with six switches while the back-end dc-dc …

Investigation On The Benefits Of Safety Margin Improvement In Candu Nuclear Power Plant Using An Fpga-Based Shutdown System, Jingke She

Electronic Thesis and Dissertation Repository

The relationship between response time and safety margin of CANadian Deuterium Uranium (CANDU) nuclear power plant (NPP) is investigated in this thesis. Implementation of safety shutdown system using Field Programmable Gate Array (FPGA) is explored. The fast data processing capability of FPGAs shortens the response time of CANDU shutdown systems (SDS) such that the impact of accident transient can be reduced. The safety margin, which is closely related to the reactor behavior in the event of an accident, is improved as a result of such a faster shutdown process.

Theoretical analysis based on neutron dynamic theory is carried out to …