Converter Supply Transformer For LVDC Distribution System

This master’s thesis is focused on optimizing the parameters of a distribution transformer with respect to low voltage direct current (LVDC) distribution system. One of the main parts of low voltage direct current (LVDC) distribution system is transformer. It is studied from several viewpoints like filtering capabilities of harmonics caused by rectifier, losses and short circuit current limiting Determining available short circuit currents is one of the most important aspects of designing power distribution systems. Short circuits and their effects must be considered in selecting electrical equipment, circuit protection and other devices.

Frequency converter protection against supply network phenomena

This master’s thesis is focused on power supply network disturbances and their effects on the frequency converter – one of the components of modern process crane electrical system. The most critical disturbance types, their causes and the effect they bring to crane electrical system was determined in this work. Variety of protective devices used for mitigation of disturbances is investigated. Device protection solutions for the frequency converter used in crane applications are presented. Analyses of the power supply requirements for frequency converter and various components of crane electrical system were carried out and as a result the crane power supply requirements list that guarantees normal crane operation was built. This list is to be included in crane projects for troubleshooting purposes in order to determine potentially dangerous network.

Energy Efficiency in Electrical Drive Systems: Technical potentials, barriers and policy approaches for small and medium industries in Ghana

Today industries and commerce in Ghana are facing enormous energy challenge. The pressure is on for industries to reduce energy consumption, lower carbon emissions and provide se-cured power supply. Industrial electric motor energy efficiency improvement is one of the most important tools to reduce global warming threat and reduce electricity bills. In order to develop a strategic industrial energy efficiency policy, it is therefore necessary to study the barriers that inhibit the implementation of cost – effective energy efficiency measures and the driving forces that promote the implementation. The aim of this thesis is to analyse the energy consumption pattern of electric motors, study factors that promote or inhibit energy efficiency improvements in EMDS and provide cost – effective solutions that improve energy efficiency to bridge the existing energy efficiency gap in the surveyed industries. The results from this thesis has revealed that, the existence of low energy efficiency in motor-driven systems in the surveyed industries were due to poor maintenance practices, absence of standards, power quality issues, lack of access to capital and limited awareness to the im-portance of energy efficiency improvements in EMDS. However, based on the results pre-sented in this thesis, a policy approach towards industrial SMEs should primarily include dis-counted or free energy audit in providing the industries with the necessary information on potential energy efficiency measures, practice best motor management programmes and estab-lish a minimum energy performance standard (MEPS) for motors imported into the country. The thesis has also shown that education and capacity development programmes, financial incentives and system optimization are effective means to promote energy efficiency in elec-tric motor – driven systems in industrial SMEs in Ghana

A game theoretic simulation model for quality oriented timber supply to sawmills

Summary

Relationship between electrical conductivity and water content in peat growth medium

Tiivistelmä: Turvekasvualustan sähkönjohtavuuden ja vesipitoisuuden riippuvuus mitattuna TDR-käsimittarilla

Effects of variety, soil type and nitrogen fertilizer supply on the nutritive value of barley for growing pigs

Selostus: Lajikkeen, typpilannoitustason ja maalajin vaikutus ohran ruokinnalliseen arvoon lihasioilla

Supply of nutrients and productive responses in dairy cows given diets based on restrictively fermented silage

Selostus: Ravintoaineiden saantiin ja maidontuotantoon vaikuttavat tekijät runsaalla säilörehuruokinnalla

Relationship of breast fillet deboning time to shear force, pH, cooking loss and color in broilers stunned by high electrical current

Selostus: Korkealla virranvoimakkuudella tainnutettujen broilereiden rintafileen irroitushetken vaikutus lihaksen leikkausvoiman vastukseen, pH:hon, keittohävikkiin ja väriin

Responses of soil respiration and barley growth to modified supply of oxygen in the soil

Selostus: Maan hengityksen ja ohran kasvun reagointi hapensaannin muutoksiin maassa

Optimizing the supply chain strategy of a multi-unit Finnish nursery company

Abstract