Lämminvesivaraajan ohjaus automaatiolla aurinkosähköä tuottavassa kotitaloudessa

Hajautettu sähköntuotanto aurinkopaneeleilla on Suomessa kasvussa. Kotitalouksiin asennettujen aurinkopaneelijärjestelmien määrä kasvaa jatkuvasti, mutta suuri osa tuotetusta sähköenergiasta syötetään sähköverkkoon. Tämä johtuu aurinkosähkön tuotannon painottumisesta kesäpäiviin, jolloin kotitalouksien kulutus on pienimmillään. Suurin hyöty itse tuotetusta energiasta saadaan kuitenkin käyttämällä se tuotantokohteessa, jolla minimoidaan energiansiirto sähköverkon ja kotitalouden rajapinnassa. Siirtämällä kotitalouden suurimpia kuormia aurinkosähkön mukaan ohjatuksi, voidaan saavuttaa merkittäviä parannuksia tuotetun sähkön omakäyttöasteessa. Helpoimmillaan tämä onnistuu kellokytkimellä, joka ajoittaa kulutuksen parhaimman tuotannon ajalle. Tämä ei kuitenkaan poista ongelmaa tilanteissa, jossa aurinkosähkön tuotanto on häiriintynyt esimerkiksi pilvisyyden takia aamupäivällä ja huipputuotanto saavutetaan vasta iltapäivän puolella. Saatavilla on jo useita järjestelmiä, jotka ohjaavat kodin laitteita tuotannon mukaisesti. Suuri osa näistä järjestelmistä on kuitenkin suunniteltu toimimaan vain tuotetun energiamäärän mukaisesti, ottamatta huomioon kotitaloudessa olevaa muuta, automaation piiriin kuulumatonta kulutusta. Tässä kandidaatin työssä vertaillaan sähköenergian eri mittaustapoja ja niiden vaikutusta siirretyn energian laskennalliseen määrään. Lisäksi työssä tutkitaan lämminvesivaraajan kuormanohjausta käyttäen termostaatti-, kellokytkin- ja logiikkaohjausta. Työssä esitelty logiikkaohjaus hyödyntää siirretyn energian mittausta sähköverkon ja kotitalouden rajapinnassa, ottaen automaattisesti huomioon myös talouden muun kulutuksen. Työssä esitellään myös esimerkkilaitteisto, jolla suunniteltu logiikka voidaan toteuttaa.

Distributed energy resources in an electricity retailer’s short-term profit optimization

Liberalization of electricity markets has resulted in a competed Nordic electricity market, in which electricity retailers play a key role as electricity suppliers, market intermediaries, and service providers. Although these roles may remain unchanged in the near future, the retailers’ operation may change fundamentally as a result of the emerging smart grid environment. Especially the increasing amount of distributed energy resources (DER), and improving opportunities for their control, are reshaping the operating environment of the retailers. This requires that the retailers’ operation models are developed to match the operating environment, in which the active use of DER plays a major role. Electricity retailers have a clientele, and they operate actively in the electricity markets, which makes them a natural market party to offer new services for end-users aiming at an efficient and market-based use of DER. From the retailer’s point of view, the active use of DER can provide means to adapt the operation to meet the challenges posed by the smart grid environment, and to pursue the ultimate objective of the retailer, which is to maximize the profit of operation. This doctoral dissertation introduces a methodology for the comprehensive use of DER in an electricity retailer’s short-term profit optimization that covers operation in a variety of marketplaces including day-ahead, intra-day, and reserve markets. The analysis results provide data of the key profit-making opportunities and the risks associated with different types of DER use. Therefore, the methodology may serve as an efficient tool for an experienced operator in the planning of the optimal market-based DER use. The key contributions of this doctoral dissertation lie in the analysis and development of the model that allows the retailer to benefit from profit-making opportunities brought by the use of DER in different marketplaces, but also to manage the major risks involved in the active use of DER. In addition, the dissertation introduces an analysis of the economic potential of DER control actions in different marketplaces including the day-ahead Elspot market, balancing power market, and the hourly market of Frequency Containment Reserve for Disturbances (FCR-D).

Power Electronic Converters in Low-Voltage Direct Current Distribution – Analysis and Implementation

Over the recent years, smart grids have received great public attention. Many proposed functionalities rely on power electronics, which play a key role in the smart grid, together with the communication network. However, “smartness” is not the driver that alone motivates the research towards distribution networks based on power electronics; the network vulnerability to natural hazards has resulted in tightening requirements for the supply security, set both by electricity end-users and authorities. Because of the favorable price development and advancements in the field, direct current (DC) distribution has become an attractive alternative for distribution networks. In this doctoral dissertation, power electronic converters for a low-voltage DC (LVDC) distribution system are investigated. These include the rectifier located at the beginning of the LVDC network and the customer-end inverter (CEI) on the customer premises. Rectifier topologies are introduced, and according to the LVDC system requirements, topologies are chosen for the analysis. Similarly, suitable CEI topologies are addressed and selected for study. Application of power electronics into electricity distribution poses some new challenges. Because the electricity end-user is supplied with the CEI, it is responsible for the end-user voltage quality, but it also has to be able to supply adequate current in all operating conditions, including a short-circuit, to ensure the electrical safety. Supplying short-circuit current with power electronics requires additional measures, and therefore, the short-circuit behavior is described and methods to overcome the high-current supply to the fault are proposed. Power electronic converters also produce common-mode (CM) and radio-frequency (RF) electromagnetic interferences (EMI), which are not present in AC distribution. Hence, their magnitudes are investigated. To enable comprehensive research on the LVDC distribution field, a research site was built into a public low-voltage distribution network. The implementation was a joint task by the LVDC research team of Lappeenranta University of Technology and a power company Suur-Savon S¨ahk¨o Oy. Now, the measurements could be conducted in an actual environment. This is important especially for the EMI studies. The main results of the work concern the short-circuit operation of the CEI and the EMI issues. The applicability of the power electronic converters to electricity distribution is demonstrated, and suggestions for future research are proposed.

Dynamic Modelling of Circulating Fluidized Bed Plant with Gas Turbine Repowering

Increasing amount of renewable energy source based electricity production has set high load control requirements for power grid balance markets. The essential grid balance between electricity consumption and generation is currently hard to achieve economically with new-generation solutions. Therefore conventional combustion power generation will be examined in this thesis as a solution to the foregoing issue. Circulating fluidized bed (CFB) technology is known to have sufficient scale to acts as a large grid balancing unit. Although the load change rate of the CFB unit is known to be moderately high, supplementary repowering solution will be evaluated in this thesis for load change maximization. The repowering heat duty is delivered to the CFB feed water preheating section by smaller gas turbine (GT) unit. Consequently, steam extraction preheating may be decreased and large amount of the gas turbine exhaust heat may be utilized in the CFB process to reach maximum plant electrical efficiency. Earlier study of the repowering has focused on the efficiency improvements and retrofitting to maximize plant electrical output. This study however presents the CFB load change improvement possibilities achieved with supplementary GT heat. The repowering study is prefaced with literature and theory review for both of the processes to maximize accuracy of the research. Both dynamic and steady-state simulations accomplished with APROS simulation tool will be used to evaluate repowering effects to the CFB unit operation. Eventually, a conceptual level analysis is completed to compare repowered plant performance to the state-of-the-art CFB performance. Based on the performed simulations, considerably good improvements to the CFB process parameters are achieved with repowering. Consequently, the results show possibilities to higher ramp rate values achieved with repowered CFB technology. This enables better plant suitability to the grid balance markets.

Triadic Perspective to Sport Sponsorship Relationships

Often the empirical studies about sport sponsorship co-operation have concentrated on the relationships between the sponsor and the sponsored target excluding the phenomenon sports manager, i.e. the intermediating actor from further examination. In this study the purpose was to contribute to the research gap in the current literature by thoroughly describing the roles and relationships in the sport sponsorship co-operation that includes an intermediating actor, that is a triad. The main objective was pursued to fulfill with the help of two sub-level research questions that were identified as ”What is the nature of the sport sponsorship triad?” and ”What is the role of the intermediating actor within the sport sponsorship triad?” First, the theorethical framework was constructed based on the existing literature of business relationship triads and sponsorship co-operation that were integrated in the synthesis of the theories the purpose of which was to produce a framework for empirical research. Then a qualitative research was conducted by using a single-case study approach. The data was collected through a semi-structured theme interview in person with the sports manager. Similar questionnaires were sent out to the sponsor and the athlete and answered in writing. After collecting the data, the actor roles’ and their relationships were examined individually, after which the analysis of the results was carried out and divided according to the research questions. The nature of the sport sponsorship triad was found to be a serial triad that could be likened to a system of two dyads connected by the intermediating actor. Each actor seemed to occupy a specific justifiable position within the co-operation, even though the relationships were found to be unbalanced in terms of resources, power/strength, interaction patterns and interconnectedness. The core role of the intermediating actor was found to be the role of a mediator, which was seen to increase the other parties’ dependence of the manager’s performance. Therefore, the role of the intermediating actor should be considered crucial for the very existence of the sport sponsorship co-operation, especially in cases where the nature of the triad is a serial triad.

Loistehon kompensoinnin ja yliaaltosuodattimien nykytila sekä kehityskohteet Kemira Chemicals Oy:n Joutsenon tehtaalla

Tutkimuksessa käsitelty kemikaalitehdas on 110 kV:n kantaverkkoon liittyvä tehointensiivinen teollisuuslaitos. Prosessien käyttöön mukautetut sähkönjakeluverkon yliaaltosuodattimet ja niiden käyttökytkennät ovat tärkeässä asemassa loistehon tuoton hallitsemiseksi liittymän loistehoikkunaan ja riittävän yliaaltosuodatuksen järjestämiseksi häviöt minimoiden. Kohteena olleen kemikaalitehtaan sähkönjakeluverkon kompensointia ja yliaaltosuodatusta on viimeksi tutkittu vuonna 2003. Tämän jälkeen verkostokomponentit ovat ikääntyneet, prosessien käyttö sekä pienjänniteverkko ovat muuttuneet ja tehdasta käyttävät osittain eri henkilöt. Nykytilaselvitykselle ja verkon kehityskohteiden analysoinnille on tullut tarve edellisen selvityksen jatkoksi. Tutkimus painottuu vahvasti kenttämittauksiin, joiden perusteella sekä kirjallisuutta ja tehtaan järjestelmiä hyödyntäen määritetään loistehotasot verkon keskeisimmissä kohteissa pien-, keski- ja suurjännitetasoilla. Tutkimuksessa esitetään lipeätehtaan suotimien uudelleenjärjestely 4. yliaallon vähentämiseksi ja yksikkökoon pienentämiseksi. Kantaverkon liittymäpisteen tilanne oli hyväksyttävä. Tutkimus esittää pienjännitekompensointia KF-4-100 keskukseen varayhteyden kapasiteettia lisäten. Tutkimus tuotti yleistietoutta verkon käytöstä ja selvitti parhaat käyttökytkennät loistehoikkunan hallitsemiseksi ilman loistehokustannuksia.

Viologen based electroactive polymers and composites for durable electrochromic systems

Electrochromism, the phenomenon of reversible color change induced by a small electric charge, forms the basis for operation of several devices including mirrors, displays and smart windows. Although, the history of electrochromism dates back to the 19th century, only the last quarter of the 20th century has its considerable scientific and technological impact. The commercial applications of electrochromics (ECs) are rather limited, besides top selling EC anti-glare mirrors by Gentex Corporation and airplane windows by Boeing, which made a huge commercial success and exposed the potential of EC materials for future glass industry. It is evident from their patents that viologens (salts of 4,4ʹ-bipyridilium) were the major active EC component for most of these marketed devices, signifying the motivation of this thesis focusing on EC viologens. Among the family of electrochromes, viologens have been utilized in electrochromic devices (ECDs) for a while, due to its intensely colored radical cation formation induced by applying a small cathodic potential. Viologens can be synthesized as oligomer or in the polymeric form or as functionality to conjugated polymers. In this thesis, polyviologens (PVs) were synthesized starting from cyanopyridinium (CNP) based monomer precursors. Reductive coupling of cross-connected cyano groups yields viologen and polyviologen under successive electropolymerization using for example the cyclic voltammetry (CV) technique. For further development, a polyviologen-graphene composite system was fabricated, focusing at the stability of the PV electrochrome without sacrificing its excellent EC properties. High electrical conductivity, high surface area offered by graphene sheets together with its non-covalent interactions and synergism with PV significantly improved the electrochrome durability in the composite matrix. The work thereby continued in developing a CNP functionalized thiophene derivative and its copolymer for possible utilization of viologen in the copolymer blend. Furthermore, the viologen functionalized thiophene derivative was synthesized and electropolymerized in order to explore enhancement in the EC contrast and overall EC performance. The findings suggest that such electroactive viologen/polyviologen systems and their nanostructured composite films as well as viologen functionalized conjugated polymers, can be potentially applied as an active EC material in future ECDs aiming at durable device performances.

Particle swarm optimization for two-connected networks with bounded rings

The Two-Connected Network with Bounded Ring (2CNBR) problem is a network design problem addressing the connection of servers to create a survivable network with limited redirections in the event of failures. Particle Swarm Optimization (PSO) is a stochastic population-based optimization technique modeled on the social behaviour of flocking birds or schooling fish. This thesis applies PSO to the 2CNBR problem. As PSO is originally designed to handle a continuous solution space, modification of the algorithm was necessary in order to adapt it for such a highly constrained discrete combinatorial optimization problem. Presented are an indirect transcription scheme for applying PSO to such discrete optimization problems and an oscillating mechanism for averting stagnation.

Repertory grid adaptations in detecting connotative trends and social behaviour problems in education

Please consult the paper edition of this thesis to read. It is available on the 5th Floor of the Library at Call Number: Z 9999 E38 K66 1983

Buried Treasure: The Economics of Leak Detection and Water Loss Prevention in Ontario

On average approximately 13% of the water that is withdrawn by Canadian municipal water suppliers is lost before it reaches final users. This is an important topic for several reasons: water losses cost money, losses force water agencies to draw more water from lakes and streams thereby putting more stress on aquatic ecosystems, leaks reduce system reliability, leaks may contribute to future pipe failures, and leaks may allow contaminants to enter water systems thereby reducing water quality and threatening the health of water users. Some benefits of leak detection fall outside water agencies’ accounting purview (e.g. reduced health risks to households connected to public water supply systems) and, as a result, may not be considered adequately in water agency decision-making. Because of the regulatory environment in which Canadian water agencies operate, some of these benefits-especially those external to the agency or those that may accrue to the agency in future time periods- may not be fully counted when agencies decide on leak detection efforts. Our analysis suggests potential reforms to promote increased efforts for leak detection: adoption of a Canada-wide goal of universal water metering; development of full-cost accounting and, pricing for water supplies; and co-operation amongst the provinces to promulgate standards for leak detection efforts and provide incentives to promote improved efficiency and rational investment decision-making.

Region Connection Calculus: Composition Tables and Constraint Satisfaction Problems

Qualitative spatial reasoning (QSR) is an important field of AI that deals with qualitative aspects of spatial entities. Regions and their relationships are described in qualitative terms instead of numerical values. This approach models human based reasoning about such entities closer than other approaches. Any relationships between regions that we encounter in our daily life situations are normally formulated in natural language. For example, one can outline one's room plan to an expert by indicating which rooms should be connected to each other. Mereotopology as an area of QSR combines mereology, topology and algebraic methods. As mereotopology plays an important role in region based theories of space, our focus is on one of the most widely referenced formalisms for QSR, the region connection calculus (RCC). RCC is a first order theory based on a primitive connectedness relation, which is a binary symmetric relation satisfying some additional properties. By using this relation we can define a set of basic binary relations which have the property of being jointly exhaustive and pairwise disjoint (JEPD), which means that between any two spatial entities exactly one of the basic relations hold. Basic reasoning can now be done by using the composition operation on relations whose results are stored in a composition table. Relation algebras (RAs) have become a main entity for spatial reasoning in the area of QSR. These algebras are based on equational reasoning which can be used to derive further relations between regions in a certain situation. Any of those algebras describe the relation between regions up to a certain degree of detail. In this thesis we will use the method of splitting atoms in a RA in order to reproduce known algebras such as RCC15 and RCC25 systematically and to generate new algebras, and hence a more detailed description of regions, beyond RCC25.

Map - Plan of Operation against Cantigny

A map titled "Plan of Operation against Cantigny" and dated 17 December 1918.

Pointers on Design and Operation of Cattle Restrainer Systems

The article discusses the importance of design and the people who run handling systems.

Note to S.D. Woodruff regarding the plan of operation

Note to S.D. Woodruff regarding the plan of operation. First, “draw up a report showing the cost of work”. This note is unsigned, n.d.