Rovakaira Oy:n keskijänniteverkon kehittämissuunnitelma toimitusvarmuuskriteeristön näkökulmasta

Diplomityössä tavoitteena on etsiä teknistaloudellisimmat ratkaisut sekä tutkia niiden vaikutuksia sähkönjakeluverkoston käyttövarmuuteen ja luotettavuuteen toimitusvarmuuskriteeristön näkökulmasta. Lisäksi työssä esitetään uusi tunnusluku kriteeristön ylityksestä aiheutuvan haitan arvostukseen. Merkittävä osa Rovakaira Oy:n keskijänniteverkosta joudutaan uusimaan lähivuosikymmeninä teknistaloudellisen pitoajan täyttyessä. Verkon uusiminen antaa mahdollisuuden toteuttaa verkkoa nykyisiin vaatimuksiin paremmin sopivilla ratkaisuilla. Kehitysvaihtoehtoina vertaillaan johdon tien varteen siirtoa, maastokatkaisijoiden lisäämistä, pienitehoisten ja päättyvien haarajohtojen korvaamista 1 kV tekniikalla sekä pienoissähköaseman kannattavuutta. Työssä tarkastellaan yksityiskohtaisemmin Sodankylän käyttövarmuuden parantamista sähköasemavian aikana ja alueen kuormituksenkasvuun varautumista.

Keskijänniteverkon maakaapeloinnin kannattavuus

Tämän työn tavoitteena oli löytää tekijöitä jotka vaikuttavat keskijänniteverkon maakaapeloinnin kannattavuuteen. 1950–1970 luvuilla verkkoa rakennettiin halvimmalla mahdollisella tavalla, eikä sähkönjakelun luotettavuuteen kiinnitetty huomiota. Tämä tuo verkkoyhtiöille haasteen vanhoja verkkoja saneerattaessa, sillä keskeytyskustannusten arvostus on noussut merkittävään asemaan. Työssä tarkoituksena oli vertailla avojohdon sekä maakaapeloinnin elinkaarikustannuksia kahden erilaisen johtolähdön avulla. Toisella johtolähdöllä oli suuri julkinen kuorma ja toinen johtolähtö oli pitkä maaseutulähtö jolla esiintyi paljon vikoja. Työssä tarkastellaan myös sähkönjakeluverkon käyttövarmuutta ja maakaapeloinnin ominaisuuksia. Elinkaarikustannuksiin vaikuttavia tekijöitä olivat investointikustannukset, keskeytyskustannukset sekä ylläpitokustannukset. Tuloksista voidaan huomata, että keskeytyskustannuksilla voi olla joissain tapauksissa hyvinkin suuri vaikutus johtolähdön elinkaareen. Pitkillä ja pienitehoisilla johtolähdöillä keskeytyskustannusten merkitys pienenee, eikä kaapeloinnilla saavuteta yhtä suurta hyötyä kuin suuritehoisemmilla lähdöillä.

Kaivoslastauskoneen hybridisointianalyysi virtuaali- ja in-loop -simuloinnin avulla

Työssä tutkitaan raskaiden työkoneiden hybridisointimitoitusta simuloimalla. Työssä esitetään simulation-in-the-loop-simulointiin perustuva järjestelmä, jolla esimerkkitapauksena oleva kaivoslastauskone työympäristöineen voidaan mallintaa mekaaniselta osaltaan monikappaledynamiikkaan perustuvalla ohjelmistolla ja hybridijärjestelmän osalta Simulinkissa. Yhdistetty simulointi mahdollistaa hybridityökoneen virtuaalimallin ohjaamisen käyttäjän toimesta reaaliajassa. Simuloinnista saadaan tuloksena mm. työsykli, jota voidaan käyttää hybridisointimitoitukseen. Hybridisointi toteutetaan kahdella erilaisella kokoonpanolla, joista analysoidaan suorituskykyä sekä polttoaineen kulutusta. Tuloksia verrataan pelkästään dieselmoottoria voimanlähteenä käyttävään lastauskoneeseen. Työssä tehty tutkimus osoittaa, että (sarja-) hybridisoinnilla voidaan saavuttaa merkittäviä etuja raskaiden työkoneiden polttoainetehokkuudessa. Dieselmoottoria voidaan ajaa sellaisessa staattisessa toimintapisteessä, jonka hyötysuhde on korkea riippumatta työkoneen kuormituksesta. Saavutettu hyöty on toteutetussa tutkimuksessa parhaimmillaan jopa 56 % vähennys polttoaineenkulutuksessa. Lisäksi tarvittava dieselin nimellisteho pienenee huomattavasti. Tutkimuksen osana esitellään myös Hardware-in-the-Loop -laitteisto, jonka avulla voidaan liittää oikea sähkömoottori ja taajuudenmuuttaja osaksi virtuaalisesti simuloitua työkonetta.

Säteilysuojelu käytetyn ydinpolttoaineen kapselointi- ja loppusijoituslaitoksella

Suomen ydinenergialaki vaatii ydinenergian käytössä syntyvän ydinjätteen käsittelyn ja varastoinnin sekä loppusijoittamisen Suomeen. Fortumin ja TVO:n ydinvoimalaitoksissa syntyvä käytetty ydinpolttoaine tullaan kapseloimaan ja loppusijoittamaan Olkiluotoon rakennettavassa kapselointi- ja loppusijoituslaitoksessa. Tämän työn tavoitteena on muodostaa kokonaiskuva kapselointi- ja loppusijoituslaitoksen säteilysuojelusta aikaisemmin tehtyjen selvitysten ja suunnitelmien perusteella. Kapselointilaitoksella käytetty ydinpolttoaine suljetaan kuparikapseleihin, jotka loppusijoitetaan maan alle loppusijoituslaitoksella. Työn aluksi kuvataan loppusijoitusmenetelmä ja kapselointi- ja loppusijoituslaitoksen käyttötoiminta. Tämän jälkeen käsitellään lainsäädäntöä ja viranomaisohjeita, jotka ohjaavat ydinlaitosten säteilysuojelua. Seuraavaksi käsitellään kapselointi- ja loppusijoituslaitoksella olevia säteilylähteitä. Lisäksi työssä käsitellään kapselointi- ja loppusijoituslaitokselle suunniteltua valvonta-aluetta ja sen säteilyolosuhteiden mukaista vyöhykejakoa. Työssä saatiin tulokseksi kokonaiskuva kapselointi- ja loppusijoituslaitoksen säteilysuojelusta. Kokonaiskuvan muodostamisen lisäksi laadittiin alustavia suunnitelmia käyttötoiminnan säteilysuojelun järjestämisestä. Lisäksi laadittiin ehdotuksia valvonta-alueen tarkemmista rajoista loppusijoituslaitoksella sekä havaittiin laitosten säteilysuojeluun liittyviä ongelmia ja esitettiin ratkaisuja niihin. Ongelmaksi osoittautui muun muassa, että kapselointi- ja loppusijoituslaitoksen valvonta-alueiden luonteiden eroa ei ollut huomioitu suunnitelmissa. Lisäksi todettiin, että nykyisin ydinlaitoksilla käytössä oleva valvonta-alueen vyöhykejako ei vastaa kapselointi- ja loppusijoituslaitosten tarpeita. Näihin esitettiin ratkaisuiksi laitosten välille perustettavaa kenkärajaa ja uuden korkeamman säteilyvyöhykkeen käyttöönottoa.

Strategic planning of major disturbance proof network

In the 2000’s Finland suffered from storms that caused long outages in electricity distribution, longest up to two weeks. These major disturbances increased the importance of supply security. In 2013 new Electricity Market Act was announced. It defined maximum duration for outages, 6 h for city plan areas and 36 h for other areas. The aim for this work is to determine required major disturbance proof level for a study area and find tools for prioritizing overhead lines for cabling renovation to improve supply security. Three prioritization methods were chosen to be studied: A: prioritization line sections by customer outage costs they cause, B: maximizing customers major disturbance proof network and C: minimizing excavation costs in medium voltage network. Profitability calculations showed that prioritization method A was the most profitable and C had the weakest profitability. The prioritization method C drove renovation into unreasonable locations in the study area in reliability point of view. Therefore universal rule prioritization methods couldn’t be made from the prioritization methods. This led to the conclusion that every renewing area need to be evaluated in a case by case basis.

Novel virtual environment and real-time simulation based methods for improving life-cycle efficiency of non-road mobile machinery

Virtual environments and real-time simulators (VERS) are becoming more and more important tools in research and development (R&D) process of non-road mobile machinery (NRMM). The virtual prototyping techniques enable faster and more cost-efficient development of machines compared to use of real life prototypes. High energy efficiency has become an important topic in the world of NRMM because of environmental and economic demands. The objective of this thesis is to develop VERS based methods for research and development of NRMM. A process using VERS for assessing effects of human operators on the life-cycle efficiency of NRMM was developed. Human in the loop simulations are ran using an underground mining loader to study the developed process. The simulations were ran in the virtual environment of the Laboratory of Intelligent Machines of Lappeenranta University of Technology. A physically adequate real-time simulation model of NRMM was shown to be reliable and cost effective in testing of hardware components by the means of hardware-in-the-loop (HIL) simulations. A control interface connecting integrated electro-hydraulic energy converter (IEHEC) with virtual simulation model of log crane was developed. IEHEC consists of a hydraulic pump-motor and an integrated electrical permanent magnet synchronous motorgenerator. The results show that state of the art real-time NRMM simulators are capable to solve factors related to energy consumption and productivity of the NRMM. A significant variation between the test drivers is found. The results show that VERS can be used for assessing human effects on the life-cycle efficiency of NRMM. HIL simulation responses compared to that achieved with conventional simulation method demonstrate the advances and drawbacks of various possible interfaces between the simulator and hardware part of the system under study. Novel ideas for arranging the interface are successfully tested and compared with the more traditional one. The proposed process for assessing the effects of operators on the life-cycle efficiency will be applied for wider group of operators in the future. Driving styles of the operators can be analysed statistically from sufficient large result data. The statistical analysis can find the most life-cycle efficient driving style for the specific environment and machinery. The proposed control interface for HIL simulation need to be further studied. The robustness and the adaptation of the interface in different situations must be verified. The future work will also include studying the suitability of the IEHEC for different working machines using the proposed HIL simulation method.

The influence of high cable penetration in distribution networks on earth fault currents and the operation of relay protection.

Recent Storms in Nordic countries were a reason of long power outages in huge territories. After these disasters distribution networks' operators faced with a problem how to provide adequate quality of supply in such situation. The decision of utilization cable lines rather than overhead lines were made, which brings new features to distribution networks. The main idea of this work is a complex analysis of medium voltage distribution networks with long cable lines. High value of cable’s specific capacitance and length of lines determine such problems as: high values of earth fault currents, excessive amount of reactive power flow from distribution to transmission network, possibility of a high voltage level at the receiving end of cable feeders. However the core tasks was to estimate functional ability of the earth fault protection and the possibility to utilize simplified formulas for operating setting calculations in this network. In order to provide justify solution or evaluation of mentioned above problems corresponding calculations were made and in order to analyze behavior of relay protection principles PSCAD model of the examined network have been created. Evaluation of the voltage rise in the end of a cable line have educed absence of a dangerous increase in a voltage level, while excessive value of reactive power can be a reason of final penalty according to the Finish regulations. It was proved and calculated that for this networks compensation of earth fault currents should be implemented. In PSCAD models of the electrical grid with isolated neutral, central compensation and hybrid compensation were created. For the network with hybrid compensation methodology which allows to select number and rated power of distributed arc suppression coils have been offered. Based on the obtained results from experiments it was determined that in order to guarantee selective and reliable operation of the relay protection should be utilized hybrid compensation with connection of high-ohmic resistor. Directional and admittance based relay protection were tested under these conditions and advantageous of the novel protection were revealed. However, for electrical grids with extensive cabling necessity of a complex approach to the relay protection were explained and illustrated. Thus, in order to organize reliable earth fault protection is recommended to utilize both intermittent and conventional relay protection with operational settings calculated by the use of simplified formulas.

Verkostoskenaarioiden arviointi sähkön jakeluverkkotoiminnan valvontamenetelmien kannalta

Tämän työn tavoitteena oli selvittää sähkön jakeluverkkotoiminnan valvontamenetelmien muutoksien vaikutuksia Loiste Sähköverkko Oy:n talouteen neljännellä ja viidennellä valvontajaksolla. Tarkastelua varten tehtiin talousmalli, joka mallintaa verkkoyhtiön taloutta vuoteen 2040 asti. Talousmallissa mallinnettiin kaikkien kannustimien vaikutus paitsi innovaatio- ja toimitusvarmuuskannustimien vaikutus. Talousmallinnuksen perusperiaate oli, että mitä ei pystytä kattamaan siirtotuloilla, rahoitetaan vieraalla pääomalla, kun kassavirran minimitaso ja investointitaso ovat valittu. Talousmallilla tarkasteltiin neljää erilaista verkostoskenaariota. Tarkasteltavat verkostoskenaariot olivat kehittämissuunnitelman mukainen skenaario, nopeutettu kehittämissuunnitelman mukainen skenaario, kaapelointipainotteinen skenaario ja kunnossapitopainotteinen skenaario. Verkon arvon kehittyminen verkostoskenaarioissa mallinnettiin Loiste Sähköverkko Oy:n investointimallilla ja kuvattiin talousmallinnusta varten jälleenhankinta-arvon, nykykäyttöarvon, investointien ja tasapoistojen kehittymisellä vuoteen 2029 asti. Työn tulosten perusteella kehittämissuunnitelman mukaisessa skenaariossa vieraan pääoman määrä pysyy kohtuullisena ja mahdollistaa kohtuullisen kassavirran tarkastelujakson lopussa. Nopeutetussa kehittämissuunnitelman mukaisessa skenaariossa ja kaapelointipainotteisissa skenaariossa vieraan pääoman määrä kasvaa merkittävästi, mikä voi lisätä liiketaloudellisia riskejä, mutta toisaalta mahdollistavat korkeamman kassavirran tarkastelujakson lopussa. Kunnossapitopainotteisessa skenaariossa vieraan pääoman määrä on matala, mutta kassavirta myös pysyy matalana tarkastelujakson loppuun asti.

Modelling of faults in low-voltage cables

Power line modelling has become an interesting research area in recent years as a result of advances in the power line distribution network system. Extensive knowledge about the power line cable characteristics can be implemented in a software algorithm in a modern broadband power-line communication modem. In this study, a novel approach for modelling power line cables (AMCMK) based on the broadband impedance spectroscopy (BIS) and transmission line matrix (TLM) techniques is recommended in characterizing a healthy cable and the various faults associated with low-voltage cables for both open and short circuit situation. Models for different cable conditions are developed and tuned, which include six models for both healthy and faulty cables situations. The models are on the basis of impedance response analysis of the cable. The resulting spectra from the simulations are also cross-correlated to determine the degree of similarities between the healthy cable spectra and their respective faulty spectra.

Exploring the feasibility of applying data mining for library reference service improvement : a case study of Turku Main Library

Data mining, as a heatedly discussed term, has been studied in various fields. Its possibilities in refining the decision-making process, realizing potential patterns and creating valuable knowledge have won attention of scholars and practitioners. However, there are less studies intending to combine data mining and libraries where data generation occurs all the time. Therefore, this thesis plans to fill such a gap. Meanwhile, potential opportunities created by data mining are explored to enhance one of the most important elements of libraries: reference service. In order to thoroughly demonstrate the feasibility and applicability of data mining, literature is reviewed to establish a critical understanding of data mining in libraries and attain the current status of library reference service. The result of the literature review indicates that free online data resources other than data generated on social media are rarely considered to be applied in current library data mining mandates. Therefore, the result of the literature review motivates the presented study to utilize online free resources. Furthermore, the natural match between data mining and libraries is established. The natural match is explained by emphasizing the data richness reality and considering data mining as one kind of knowledge, an easy choice for libraries, and a wise method to overcome reference service challenges. The natural match, especially the aspect that data mining could be helpful for library reference service, lays the main theoretical foundation for the empirical work in this study. Turku Main Library was selected as the case to answer the research question: whether data mining is feasible and applicable for reference service improvement. In this case, the daily visit from 2009 to 2015 in Turku Main Library is considered as the resource for data mining. In addition, corresponding weather conditions are collected from Weather Underground, which is totally free online. Before officially being analyzed, the collected dataset is cleansed and preprocessed in order to ensure the quality of data mining. Multiple regression analysis is employed to mine the final dataset. Hourly visits are the independent variable and weather conditions, Discomfort Index and seven days in a week are dependent variables. In the end, four models in different seasons are established to predict visiting situations in each season. Patterns are realized in different seasons and implications are created based on the discovered patterns. In addition, library-climate points are generated by a clustering method, which simplifies the process for librarians using weather data to forecast library visiting situation. Then the data mining result is interpreted from the perspective of improving reference service. After this data mining work, the result of the case study is presented to librarians so as to collect professional opinions regarding the possibility of employing data mining to improve reference services. In the end, positive opinions are collected, which implies that it is feasible to utilizing data mining as a tool to enhance library reference service.

Tapes, Transgression and Mundanity: the participatory engenderment of death metal and grindcore

Since its origins in the early 1980s, the popular rise of extreme metal throughout the globe has been phenomenal. The emergence of extreme metal's most sonically transgressive subgenres of death metal and grindcore between the mid 1980s and the early 1990s, however, was not an easy one. Indeed, during this period, the only way for globally dispersed extreme metal fans and unsigned extreme metal bands to stay musically connected was via the underground practice of tape-trading. The aim of this study is to illuminate the impact of tape-trading upon the global spread of extreme metal. The study will situate the historical context of extreme metal tape-trading by exploring how it emerged, and why it was necessary in the first place. Utilising the concept of 'extreme metal scene', the study will focus on the central scenic discourse of transgression and explore how this was negotiated into the mundane scenic practice of tape-trading. In relation to this, and utilising the concept of participatory culture, the study will further explore how the music arose and spread throughout the globe via the socially networked practice of both musician and non-musician tape-traders in relation to the tape cassette technology itself. Ethnographic interviews were undertaken with both types of traders in order to gain a deeper understanding of the phenomenon in question. The research concludes that the tape-traders were able to challenge the status quo of record company gatekeepers, by facilitating the engenderment and global distribution (including the later commercial distribution) of death metal and grindcore. Such powerfully affective music via its continual global spread, offers as it did for the original tape-traders, a pleasurable and empowering communal/personal space for disempowered people throughout the globe. Further research into extreme metal tape-trading would require deeper exploration into other extreme metal subgenres, especially black metal, tape-traders situated outside of North America and Europe, women tape-traders as well as exploration of the phenomenon after the early 1990s.

Tapes, Transgression and Mundanity: the participatory engenderment of death metal and grindcore

Since its origins in the early 1980s, the popular rise of extreme metal throughout the globe has been phenomenal. The emergence of extreme metal's most sonically transgressive subgenres of death metal and grindcore between the mid 1980s and the early 1990s, however, was not an easy one. Indeed, during this period, the only way for globally dispersed extreme metal fans and unsigned extreme metal bands to stay musically connected was via the underground practice of tape-trading. The aim of this study is to illuminate the impact of tape-trading upon the global spread of extreme metal. The study will situate the historical context of extreme metal tape-trading by exploring how it emerged, and why it was necessary in the first place. Utilising the concept of 'extreme metal scene', the study will focus on the central scenic discourse of transgression and explore how this was negotiated into the mundane scenic practice of tape-trading. In relation to this, and utilising the concept of participatory culture, the study will further explore how the music arose and spread throughout the globe via the socially networked practice of both musician and non-musician tape-traders in relation to the tape cassette technology itself. Ethnographic interviews were undertaken with both types of traders in order to gain a deeper understanding of the phenomenon in question. The research concludes that the tape-traders were able to challenge the status quo of record company gatekeepers, by facilitating the engenderment and global distribution (including the later commercial distribution) of death metal and grindcore. Such powerfully affective music via its continual global spread, offers as it did for the original tape-traders, a pleasurable and empowering communal/personal space for disempowered people throughout the globe. Further research into extreme metal tape-trading would require deeper exploration into other extreme metal subgenres, especially black metal, tape-traders situated outside of North America and Europe, women tape-traders as well as exploration of the phenomenon after the early 1990s.

Starch analysis as a method to discover subsistence strategies in prehistoric Finland and Estonia

Ancient starch analysis is a microbotanical method in which starch granules are extracted from archaeological residues and the botanical source is identified. The method is an important addition to established palaeoethnobotanical research, as it can reveal ancient microremains of starchy staples such as cereal grains and seeds. In addition, starch analysis can detect starch originating from underground storage organs, which are rarely discovered using other methods. Because starch is tolerant of acidic soils, unlike most organic matter, starch analysis can be successful in northern boreal regions. Starch analysis has potential in the study of cultivation, plant domestication, wild plant usage and tool function, as well as in locating activity areas at sites and discovering human impact on the environment. The aim of this study was to experiment with the starch analysis method in Finnish and Estonian archaeology by building a starch reference collection from cultivated and native plant species, by developing sampling, measuring and analysis protocols, by extracting starch residues from archaeological artefacts and soils, and by identifying their origin. The purpose of this experiment was to evaluate the suitability of the method for the study of subsistence strategies in prehistoric Finland and Estonia. A total of 64 archaeological samples were analysed from four Late Neolithic sites in Finland and Estonia, with radiocarbon dates ranging between 2904 calBC and 1770 calBC. The samples yielded starch granules, which were compared with the starch reference collection and descriptions in the literature. Cereal-type starch was identified from the Finnish Kiukainen culture site and from the Estonian Corded Ware site. The samples from the Finnish Corded Ware site yielded underground storage organ starch, which may be the first evidence of the use of rhizomes as food in Finland. No cereal-type starch was observed. Although the sample sets were limited, the experiment confirmed that starch granules have been preserved well in the archaeological material of Finland and Estonia, and that differences between subsistence patterns, as well as evidence of cultivation and wild plant gathering, can be discovered using starch analysis. By collecting large sample sets and addressing the three most important issues – preventing contamination, collecting adequate references and understanding taphonomic processes – starch analysis can substantially contribute to research on ancient subsistence in Finland and Estonia.