RELIABILITY AND AVAILABILITY ANALYSIS OF UNINTERRUPTIBLE POWER SUPPLY (UPS) SYSTEM CONFIGURATIONS

RELIABILITY AND AVAILABILITY ANALYSIS OF

UNINTERRUPTIBLE POWER SUPPLY (UPS)

SYSTEM CONFIGURATIONS

A DISSERTATION

SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE

AWARD OF THE DEGREE OF MASTER OF TECHNOLOGY

IN ELECTRICAL ENGINEERING (CONTROL SYSTEM)

BY:

DEEPAK SHARMA

NATIONAL INSTITUTE OF TECHNOLOGY KURUKSHETRA

There are many configurations of UPS. The configurations which are considered for estimating and analyzing the reliability, its parameter and availability in this dissertation work are classified into two groups i.e. Group I and Group II which are as follow

Group I

1. Online UPS with Bypass

2. Online UPS without Bypass

3. Offline UPS

4. Line-Interactive UPS (Buck/Boost)

5. Line-Interactive UPS (Ferroresonant)

Group II

1. Capacity (N) System

2. Isolated Redundant System

3. Parallel Redundant (N+1) System

4. Distributed Redundant System

5. System Plus System "2(N+1)" Redundant System

 

Análise experimental da qualidade da energia de uma microrrede fotovoltaica com back-up Becker, Luís Rodrigo-PROGRAMA PÓS-GRADUAÇÃO EM ENGENHARIA MECANICA-UNISINOS

Análise experimental da qualidade da energia de uma microrrede fotovoltaica com back-up Luís Rodrigo Becker-PROGRAMA PÓS-GRADUAÇÃO EM ENGENHARIA MECANICA-UNISINOS

Dissertação de Mestrado-UNIVERSIDADE DO VALE DO RIO DOS SINOS

Orientador: Dias, João Batista

Resumo:

Este trabalho apresenta uma análise experimental de uma microrrede fotovoltaica formada por dois subsistemas, um isolado com estocagem e outro conectado à rede. Foi verificado o seu comportamento, sua capacidade no fornecimento de energia para uma carga isolada e rede da concessionária, monitorado a qualidade da energia elétrica entregue à diferentes cargas e rede da concessionária e também quantificado os índices de performance do sistema conectado. O subsistema conectado à rede (SFCR) é formado por um painel de 1080 Wp de silício multicristalino e um inversor c.c./c.a. de 1200 W. O subsistema isolado de back-up (SFI-b) é formado por um painel de 600 Wp de silício monocristalino, controlador de carga, banco de estocagem com baterias chumbo-ácido 24 V / 210 Ah e um inversor off-grid c.c./c.a. de 1000 W. O comportamento e a capacidade do sistema são monitorados durante o atendimento de uma carga, representada por um refrigerador. A qualidade da energia é analisada através de medições de energia ativa, reativa e aparente, fator de potência e geração de correntes harmônicas pelos inversores. O SFI-b é monitorado atendendo diferentes tipos e regimes de cargas. Já o SFCR é monitorado em dias de céu claro, parcialmente encobertos e encobertos. Os índices de performance são calculados em dias de céu claro e parcialmente encoberto ao longo dos seis primeiros meses de 2016. Os resultados demonstram que o SFI-b é capaz de atender a carga de forma confiável, comutando-a automaticamente para a concessionária quando o banco de baterias atinge uma profundidade de descarga pré-definida, enquanto o SFCR injeta a energia produzida na rede da concessionária. Os indicadores de qualidade da energia do inversor do SFI-b mostraram-se adequados, permanecendo dentro dos limites citados na legislação e análogos aos apresentados pela rede da distribuidora local. Já o inversor do SFCR apresentou indicadores de qualidade de energia satisfatórios, também na maior parte do tempo dentro dos limites citados na legislação, exceto nos dias encobertos e períodos de baixa irradiância, constatando-se significativa geração de energia reativa e distorções harmônicas de corrente. Considerando a média entre dias de céu claro e parcialmente encoberto, a eficiência média global do SFCR é de 9,9% e a energia média diária entregue à rede é de 4,7 kWh. Foi verificado que a qualidade da energia produzida pelo SFI-b praticamente independe da irradiância, já o SFCR depende diretamente da irradiância e do nível de carregamento do inversor, na geração de uma energia de qualidade.

LINK NA WEB: http://www.repositorio.jesuita.org.br/handle/UNISINOS/6430

Design and Development of an X-Ray Machine Francisco Piernas Díaz-UNIVERSIDAD DE GRANADA-2019

1 Introduction

The X-Ray analysis has developed constantly over time since Wilhelm R¨ontgen discovered it’s applications. X-Rays are now used not only for simple radiography. Modern algorithms are capable of reconstruct a three dimensional view of the object, allowing us to recover important information about the inside of the object to study, for example, a human body. Ionizing radiations like X-Rays have also been used to discover the structure of the DNA thanks to X-Ray diffractometry. This project aims to explore the technologies of 2D radiography (sections 10 and 11) and 3D tomographic scans (section 12), and for that, a 3D printable machine is designed, built and tested using a long list of software, tools and parts [28]. One of these parts is an improved Zero Voltage Switching (ZVS) Mazzilli driver, optimized for higher frequency (section 2.1.3). The design and testing is done considering safety, as described in section 9. A Geiger counter is used to ensure that the device is safe to operate and that the operator is not exposed. In addition to the device, three programs written in C++ have been developed. The first one is an original implementation of the inverse Radon transform to perform tomographic reconstructions of the data gathered wih the X-Ray machine and it’s explained in appendix A. The second program, found in appendix B, uses an original algorithm for pseudocolor radiography that tries to improve other algorithms that usually saturates the color of the result. The last program is a numerical model of the Mazzilli ZVS transformer driver inside the machine and it provides useful information about the voltages and currents involved depending on some circuit parameters. It’s found in appendix C.

LINK:http://www.mediafire.com/file/ah56thrfymxohj1/Design_and_Development_of_an_X-Ray_Machine%252C_Francisco_Piernas_Diaz.pdf/file

PhD Thesis High Frequency Modeling of Power Transformers under Transients -by Kashif Imdad-Universidad Politécnica de Cataluña

LINK: https://www.tesisenred.net/bitstream/handle/10803/457774/TKI1de1.pdf?sequence=1&isAllowed=y

Abstract

This thesis presents the results related to high frequency modeling of power transformers. First, a 25kVA distribution transformer under lightning surges is tested in the laboratory and its high frequency model is proposed. The transfer function method is used to estimate its parameters. In the second part, an advanced high frequency model of a distribution transformer is introduced. In this research, the dual resonant frequency distribution transformer model introduced by Sabiha and the single resonant frequency distribution transformer model under lightning proposed by Piantini at unloaded conditions are investigated and a modified model is proposed that is capable to work on both, single and dual resonant frequencies. The simulated results of the model are validated with the results of Sabiha and Piantini that have been taken as reference. Simulations have shown that the results of the modified model, such as secondary effective transfer voltages, transferred impedances and transformer loading agree well with the previous models in both, the time and frequency domains. The achieved experimental and simulated objectives of this research are:  Methodology for determining the parameters of a power transformer.  High frequency modeling of a transformer in order to simulate its transient behavior under surges.  Modification of high frequency model for single and dual resonance frequency. The originality and methodology of this research are:  High frequency transformer model is derived by means of the transfer function method. In the literature, the transfer function method has been used in many applications such as the determination of the mechanical deformations or insulation failure of interturn windings of transformers. In this thesis, the parameters of the proposed model are estimated using the transfer function method.  Modification of high frequency model for single/dual resonance frequency using the transfer function method. The transfer function can also be used to determine the state of the transformer. The modification in the developed model using the proposed technique has been validated (by simulations).

Design of 100kVA Ultra-High Efficiency Pole Transformer by Improving Eddy Current Losses Kim, Sang-Hyun Department of Electrical Engineering Graduate School of Soongsil University

                                     3-4 Estrutura do núcleo do transformador

 Design of 100kVA Ultra-High Efficiency Pole Transformer by Improving Eddy Current Losses Kim, Sang-Hyun Department of Electrical Engineering Graduate School of Soongsil University

ABSTRACT

In Korea, electricity demand is increasing due to industrial development and economic growth. Due to the increase in power demand, transmission and distribution losses are also increasing. The transmission and distribution loss rate in Korea is 3.6% of the total electric energy, of which about 2% is caused by losses in distribution transformers. Power transformers with high capacity and voltage have already achieved high efficiency through many studies. However, Pole transformers with low capacity and voltage are in fact lacking research on high efficiency despite the fact that about 2.2 million units are installed nationwide. The purpose of this paper is to design the ultra-high efficiency pole transformer that changes the core and winding materials and it - xii - reduces the eddy current loss of the winding and other structures for the 100kVA high efficiency pole transformer. In order to analyze the advanced technology, we analyzed overseas 100kVA high efficiency pole transformer and examined the technologies necessary for product development. In addition, The eddy current loss of low voltage windings and high voltage windings was calculated using a finite element method, and the eddy current loss was reduced by changing the shape of conductor, winding arrangement, and insulating paper. In order to reduce the eddy current loss of other structures, the loss was reduced either by inserting a nonmagnetic material between the low voltage bushing terminals or by changing the shape and material of the clamp. Finally, The iron core and winding materials of transformers were designed by using an amorphous core and copper conductor to maximize efficiency, and the 100kVA ultra-high efficiency pole transformer was designed by improving the eddy current loss of the windings and other structures. In order to verify the design, a transformer with the same specifications as the design model was manufactured to validate the effect, and compared with a high efficiency pole transformer, an efficiency of 99.56%(50% load) with an efficiency increase of 0.29% was developed. The eddy current loss reduction studies presented in this paper are expected to be used as data necessary for the development of transformers with other capacities. The final developed 100kVA ultra-high efficiency pole transformer is expected to contribute to improving the efficiency of the domestic distribution system

LINK ORIGINAL: http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=87c33062fa1d9da7ffe0bdc3ef48d419

LINK: http://www.mediafire.com/file/5z8z65z43a031c9/Design_of_100kVA_Ultra-High_efficiency.pdf/file