The Swedish electrical grid has historically been robust and reliable, but with increased electrification in numerous sectors, out-phasing of nuclear power and a high market diffusion of wind power, the system is now facing challenges. The rotational energy in the system is expected to decrease as a result of higher shares of intermittent energy sources, which can affect the stability of the grid frequency negatively. To manage increased frequency drops, the new Fast Frequency Reserve (FFR) market will be implemented by June 2020 in the Nordic power system. Simultaneously, it is expected that the demand of electricity will increase significantly in the transport and industry sectors in the coming years. Several DSOs already today indicate challenges with capacity and power security and have or will implement power tariffs as an economic incentive to prevent these problems. For energy intensive customers, such as industries, it will become important to reduce power peaks to avoid high grid fees. Several peak load shaving strategies can be utilized by industries to reduce their power peaks and thus the power tariff. The aim of this study is to economically analyze peak load shaving for Swedish industries. This is done using Li-Ion BESS and DSM, and to maximize the utilization of the BESS by including energy arbitrage and FFR market participation into the analysis. Firstly, a literature review is conducted within the topics of peak load shaving strategies, energy arbitrage and ancillary services. Secondly, data is gathered in collaboration with WSP Systems – Energy, the initiators of the project, to conduct case studies on two different industries. These cases are simulated in the modeling software SAM, for technical analysis, and then economically evaluated with NPV. Also, nine scenarios are created for the emerging FFR market concerning the number of activations per year and the compensation price per activation. The results from the case studies indicate that peak load shaving of 1 – 3 % with BESS provides a positive NPV for both case industries. However, higher percentages result in negative NPVs when no additional revenue streams are included. When considering energy arbitrage, it is concluded that the additional revenues are neglectable for both industries. Participating in the FFR market provides similar trends in the results as before. The exception is valid for scenarios with high numbers of FFR activations and compensation prices, where positive NPVs for all levels of peak load shaving can be concluded. The peak load shaving strategy DSM is implemented for one of the industries, where efficiency measures are concluded to have the most impact on the economic evaluation. If all efficiency measures would be implemented, the electricity consumption would be reduced by 17 %. Additionally, the power peaks would be reduced with 18 % and result in a significantly more positive NPV than peak load shaving using BESS. A sensitivity analysis concerning BESS capital cost and power tariff price concludes that the BESS price has a strong relation to the NPV, where a BESS price reduction of 60 % results in an NPV increase of at least 100 %. BESS prices have decreased the past years and are expected to keep decreasing in the future. Hence, investments in BESS can become more profitable and attractive in the coming years. Finally, for future research, it is recommended to combine the methodology from this study together with a load forecasting method. This combined methodology could then be practically applied to case specific industries with high peak loads. / Det svenska elnätet har historiskt sett varit robust och pålitligt, men i takt med ökad elektrifiering i flera sektorer, utfasning av kärnkraft samt ökad mängd installerad vindkraft ställs nu systemet inför nya utmaningar. Bland annat förväntas rotationsenergin i systemet minska som ett resultat av högre andelar intermittenta energikällor i systemet. För att hantera detta kommer den nya Fast Frequency Reserve (FFR) marknaden finnas tillgänglig från och med juni 2020. Samtidigt förväntas även efterfrågan på el inom transport- och industrisektorn öka markant de kommande åren. Redan idag är effektbrist ett problem i vissa regioner, vilket kan komma att förvärras. Många nätägare ska eller har redan infört effekttariffer för utnyttjande av deras elnät, vilket är ett ekonomiskt incitament för att hantera effektproblematiken där kunder med en mer flexibel elkonsumtion kommer gynnas. För större elförbrukare, som exempelvis industrier, kan det bli ekonomiskt betydelsefullt att sänka sina effekttoppar och därmed undvika höga nätavgifter. För att minska effekttoppar finns ett flertal så kallade peak load shaving-strategier, som kan utnyttjas av industrier för att minska kostnaderna för effekttariffen. Syftet med denna studie är att analysera peak load shaving för svenska industrier, med hjälp av ett Li-Ion batterilagringssystem och efterfrågeflexibilitet, samt maximera utnyttjandet av batteriet genom att inkludera energiarbitrage och deltagande i FFR-marknaden i analysen. Ett första steg i arbetet är att utföra en litteraturstudie för de berörda områdena. I ett andra steg insamlas data tillsammans med WSP, initiativtagaren av projektet, för att kunna göra en fallstudie på två industrier. För dessa fallstudier undersöks de tekniska förutsättningarna för att implementera peak load shaving-strategier genom modellering i simuleringsprogrammet SAM. Sedan utreds de ekonomiska förutsättningarna för fallstudierna, där NPV används som ekonomiskt nyckeltal. Dessutom skapas nio scenarion för den kommande FFR-marknaden för att uppskatta kostnader och inkomster. Resultatet av fallstudien visar att 1 – 3 % kapade effekttoppar med batterilagring ger ett positivt NPV för båda industrierna. Över 3 % blir resultatet negativt utan ytterligare inkomstströmmar inkluderade. Energiarbitrage konstateras att bidra med marginella positiva fördelar. Vid inkludering av FFR-marknaden i analysen erhålls liknande trender i resultaten, bortsett från scenarion med relativt högt antal avrop och pris. I dessa fall blir även 4 – 10 % kapade effekttoppar ekonomiskt attraktiva. För en av industrierna utvärderas efterfrågeflexibilitet, där effektivisering av elkrävande processer har störst inflytande på resultatet. Vid implementering av samtliga effektiviseringsåtgärder skulle elkonsumtionen minska med 17 %. Dessutom minskar effekttopparna med 18 %, vilket resulterar i ett signifikant mer positivt NPV, jämfört med användningen av batterilager. En känslighetsanalys gällande batteripris och effekttariffer, konstaterade att batteripriset har en stark påverkan på NPV. Vid en batteriprisminskning på 60 % ökar NPV med minst 100 %. Därmed kan batteriinvesteringar bli mer gynnsamma och attraktiva om batteripriser fortsätter att falla, vilket flera prognoser indikerar. Slutligen rekommenderas framtida studier att kombinera metodiken från detta arbete med en prognostiseringsmetod för elanvändning i industrier. Denna kombinerade metod kan sedan praktiskt tillämpas på fallspecifika industrier med höga effekttoppar.

The global energy system is under transformation. The energy transition from a centralized, fossil fuel based energy system to a more decentralized, renewable energy based system will challenge the balancing of electricity supply and demand. This stresses the importance of grid flexibility. In this challenge, energy storage will play a valuable role as it can provide flexibility and support the renewable energy integration. More specifically, lithium-ion battery energy storage systems (Li-ion BESS) demonstrate technological advantages and valuable application possibilities in the electricity grid. This thesis examines opportunities and barriers for deployment of grid-scale Li-ion BESS in the Swedish electricity market, and provides an overview of different perspectives of possibilities with BESS from several market actors. The purpose of the exploratory study is to gain an understanding of prospects for grid-scale BESS in Sweden. Through a comprehensive literature study and an empirical study, based on fourteen interviews with various actors in the electricity market, data was collected and analyzed. The analysis of the empirical findings resulted in two tables summarizing opportunities and barriers for implementation of BESS in Sweden. The opportunities and barriers are categorized into three hierarchical levels; contextual level, power system level and BESS level, referring to where in the system the benefits or hinders are localized. Also, key discussion points related to BESS (such as storage time perspective, ownership, grid services, cost, price signals and knowledge gap) are explored and evaluated. Furthermore, to understand the possibilities for grid-scale BESS in Sweden, a potential business setup for BESS is assessed and analyzed to identify preconditions for BESS to be attractive on the Swedish electricity market. The findings of the thesis indicate that grid flexibility is most likely going to be a considerable issue within 10-20 years. By the time of the potential nuclear phase out in Sweden, there will be major instabilities in the electricity grid if solutions are not in place. Therefore, keys to grid flexibility need to be evaluated and planned for well in advance, and the findings indicate that BESS could be a possible part of the solution. Until now, the regulatory framework has been perceived as rather unclear when it comes to energy storage, which has led to uncertainties among the market actors. These unclarities are about to be clarified with new laws and regulations, which will enable potential businesses for BESS. With the changes in the regulatory framework in place, we see an opportunity with new actors on the market. Our analysis shows that the BESS owner will most likely be a commercial actor, to enable utilization of a BESS for combined applications. An important factor, affecting the possibilities of implementing BESS on the Swedish electricity market, is the cost of BESS. We consider the cost aspect as vital for the likelihood of deploying BESS in Sweden. Based on our main findings, we conclude several preconditions for the deployment of BESS in Sweden. These are; decreased costs of BESS, acceptance from market actors, increased knowledge, a trading platform for grid services provided by a BESS, coordination between markets and electricity load forecasts. We believe that if these preconditions are fulfilled, Li-ion BESS has a chance to affect and have an impact on the Swedish electricity market. / Dagens energisystem är under förändring. Det sker en omvandling där energisystemet går från att vara centraliserat och fossilbaserat till att bli mer decentraliserat och baserat på förnybar energi. Detta kommer att utmana balanseringen av elproduktion och elkonsumtion, vilket betonar vikten av flexibilitet i elnätet. I den stundande utmaningen kommer energilagring att spela en viktig roll eftersom det kan bidra med flexibilitet och samtidigt stödja integrationen av mer förnybar elproduktion. Mer specifikt har energilagersystem med litiumjon-batterier flertalet tekniska fördelar och värdefulla användningsområden i elnätet. Det här examensarbetet utforskar möjligheter och hinder för en framtida implementering av nätanslutna litiumjonbatterilager på den svenska elmarknaden och ger en överblick över perspektiv på utsikter för batterilager från flertalet marknadsaktörer. Syftet med den utforskande studien är att få en ökad förståelse för framtidsutsikterna för storskaliga batterilager i Sverige. Genom en omfattande litteraturstudie och en empirisk studie, baserad på fjorton intervjuer med olika aktörer på elmarknaden, samlades data in och analyserades. Analysen av de empiriska resultaten resulterade i två tabeller som sammanfattar möjligheter och hinder för implementering av batterilager i Sverige. Möjligheterna och hindren kategoriseras i tre hierarkiska nivåer; kontextuell nivå, kraftsystemnivå och batterilagersystemnivå, med hänvisning till var i systemet fördelarna eller barriärerna är lokaliserade. Dessutom utvärderas flera betydande diskussionsteman relaterade till batterilager (såsom lagringstid, ägande, nättjänster, kostnad, prissignaler och kunskapsluckor). För att förstå möjligheterna för att etablera batterilager i Sverige har en möjlig affärsuppställning utvärderats och analyserats. Detta för att identifiera förutsättningar för att batterilager ska vara attraktivt på den svenska elmarknaden. Examensarbetets resultat tyder på att nätflexibilitet sannolikt kommer att bli ett betydande problem inom 10-20 år. Den troliga avvecklingen av den svenska kärnkraften kommer att resultera i instabilitet i elnätet om inte lösningar finns på plats. Därför behöver lösningar för att uppnå flexibilitet i elnätet utvärderas och planeras i god tid och uppsatsens resultat visar på att batterilager kan vara en möjlig del av lösningen. Fram till nu har det funnits oklarheter i regelverket gällande energilagring, vilket har lett till osäkerheter hos marknadsaktörerna. Nya lagar och förordningar kommer att klargöra flertalet osäkerheter och möjliggöra potentiella affärer med batterilager. När det förändrade regelverket är på plats, ser vi potential för nya aktörer på marknaden. Vår analys visar på att batterilager med största sannolikhet kommer att ägas av kommersiella aktörer för att möjliggöra kombinerade användningsområden av batterilager. Möjligheterna till implementering av batterilager på den svenska elmarknaden påverkas i hög grad av kostnaden för batterilager. Vi anser att kostnadsaspekten är avgörande för sannolikheten att utnyttja batterilager i Sverige. Vår slutsats är att det finns flertalet förutsättningar för att batterilager ska bli attraktivt och lönsamt i Sverige. Dessa är; minskade kostnader för batterilager, acceptans från marknadsaktörer, ökad kunskap, en handelsplattform för nättjänster som tillhandahålls av batterilager, samordning mellan marknader samt lastprognoser. Om dessa förutsättningar uppnås anser vi att litiumjon-batterilager har en chans att påverka den svenska elmarknaden.

To enable fast charging of electric vehicles in Stockholm or sites where the electrical energy is limited and the number of chargeable vehicles increases, there is a need to investigate new solutions to comply with the future demand. The goal of this project is to investigate what the conditions are in Stockholm today and investigate what is needed to enable fast chargers in Stockholm city. Both what electrical equipment is necessary and develop a model to simulate the flow for the available energy and the demanded energy from a charging location. The result shows that battery energy storage systems can help the chargers, but to what degree depends on demand and availability. What is shown is, if the total maximum power demand is greater than the available power from the grid, a battery could be beneficial. In the scenarios, it has been enough to have a 150 kWh battery to increase the total charged energy over the day by more than two times what the grid could supply. / För att möjliggöra snabbladdning av elfordon i Stockholm eller platser där elenergin är begränsad och andelen laddbara fordon ökar måste nya lösningar undersökas för att möta framtidens behov. Målet med detta arbete är att undersöka vad det finns för förutsättningar för laddning i Stockholm i dagsläget och undersöka vad som krävs för att införa snabbladdare i Stockholms stad; vilken elektrisk utrustning som krävs samt ta fram en modell för att simulera ett flöde av tillgänglig energi och efterfråga för en laddplats.  Resultatet av studien är att batterienergilagringsystem kan hjälpa laddarna, men de bidrar olika mycket beroende på efterfrågan och energitillgång direkt från nätet. Om det totala maxeffektbehovet från laddgatan är högre än vad elnätet kan leverera kan det vara lönsamt att ha installerade batterier. I dessa scenarion har det räckt med ett batteri på 150 kWh för att kunna öka den energimängd som laddas över till elfordon under ett dygn med mer än dubbla nätets kapacitet.

One of the key challenges the world will need to face during the 21st century is global warming and the consequent climate change. Its presence is indisputable, and decarbonizing the gird emerges as one of the required pathways to achieve global sustainable objectives. Solar energy power plants have the potential to revert this situation and solve the problem. One way to harness this energy is through Concentrated Solar Power plants. The major advantage and potential of this technology is its ability to integrate cost-effective Thermal Energy Storage (TES), which is key with such an inherently intermittent resource. On the other hand, the drawback is the high current Levelized Cost of Energy (LCOE). The other main way to harness that highlighted solar energy is the use of Photovoltaic panels, which have recently achieved very competitive LCOE values. On the other hand, the storage integration is still a very pricey option, normally done with Battery Energy Storage Systems (BESS). As a conclusion, a hybrid power plant combining the LCOE of the PV and the TES of the CSP emerges as the key way of achieving a very competitive solution with a big potential. This master thesis aims at exploring the possibilities of a hybrid CSP and PV power plant with a sCO2 power cycle, integrated in the primary, secondary and tertiary electricity markets. To achieve this purpose, firstly, a Python-based Energy Dispatcher was developed to control the hybrid power plant. Indeed, the Dispatcher is the tool that decides when to produce, when to store… following an optimization problem. This can be formulated mathematically, and that was done and integrated into the Python code using Pyomo, a software for optimization problems. As a result, the Dispatcher achieved an effective control of the plant, showing intelligent decisions in detailed hourly analyses. The results were very promising and included optimization functions as maximizing the profitability of the plant or the total production, among others. To proceed with the Techno-economic assessment of the hybrid plant, the electricity markets were studied. The main source of income of any power plant is normally the revenue from selling electricity to the grid, but since there are several markets, there are also other possibilities. In this thesis, it was assessed from a Techno-Economic perspective how the performance and optimal design of the plants vary when providing different services extra to selling electricity to the grid. The conclusion was that even though the Net Present Value (NPV) achieved working on the spot market was already very high, the extra value added from participating in the secondary or tertiary markets was indisputable. Indeed, the profits attained in those markets were between two and four times higher than the ones of the spot market. This is a specific case, but a trend was identified: these hybrid power plants have a huge possibility and a bright future on the service markets. As a consequence, this thesis shows the huge potential of hybrid power plants integrated in the grid participating in several markets. It also lays the foundation for future studies in other locations, under different conditions and with different technologies, among others.

Due to the growing population and climate change, the world will see an increase in demand for food, freshwater and renewable energy supply. Agrivoltaics has the possibility to address all these problems, by producing food and renewable energy but also by reducing water usage in agriculture. This thesis aims to study if agrivoltaics including storage has the potential to enable sustainable greenhouses in Stockholm, Sweden by trying to create a near net zero energy consumption for greenhouses with Agrivoltaics (AV) implemented. Furthermore a techno-economic assessment will be made for the AV-systems where Key Performance Indicator (KPI)’s are compared to economic parameters. The selected KPI’s were a near net zero energy consumption and irradiance underneath the Photovoltaics (PV) technology. The selected PV-technology was standard PV-modules, Semi-Transparent Module (STM) and Organic Solar Cell (OSC) PV. These technologies were paired with li-ion batteries between 0-100 kWh and simulated in the software System Advisor Model (SAM) over a 25 year period. The AV system was applied to two load profiles, one for indoor plants and one for tomatoes. The economic parameters calculated was Net Present Value (NPV), Net Capital Cost (NCC), and Levelised Cost of Electricity (LCOE).  The results showed that the system is efficient in summertime where the PV reached maximum capacity in summer and the battery works as a complement. In wintertime, the AV-system is not very efficient and most of the electricity comes from the grid. It was not possible to create a near net zero energy consumption including storage in Stockholm Sweden. The irradiance beneath the panels were at a maximum for OSC, it was slightly reduced for the STM, and below 50% for the standard PV-module, depending on the size of the AV-system. Depending on the shade tolerance of the plant, the PV-technology should be selected.

In this thesis, a simulation model developed in MATLAB® in consideration of system losses based on lithium ion-battery is presented. The purpose of the simulation model is to investigate peak shaving potential in the residential distribution network. In other word to determine an optimal threshold limit and battery capacity depending on if the battery system is placed at the transformer or household level. In the report there were economic calculations executed showing that profitability of investing in a battery system depends on the threshold limit and battery capacity. / I denna rapport presenteras analys av toppeffektreducering med ett simuleringsprogram baserad på litium-jon batteri med hänsyn till systemförlust. Simuleringsmodellen är uppbyggd i MATLAB® där metoder som Coulomb counting implementerades. Syftet med simuleringsprogrammet är att definiera en optimal tröskelgräns samt batterikapacitet på transformator- och hushållsnivån. I rapporten utfördes ekonomiska beräkningar som tyder på att lönsamheten för investering av ett batterisystem beror på tröskelgräns och batterikapacitet.

The main purpose of this thesis was to develop and evaluate Key Performance Indicators (KPIs) and battery usage associated with Lithium-ion Battery Energy Storage Systems (LiBESS) used as Frequency Containment Reserve (FCR). The investigation was based on three of Vattenfall´s LiBESS projects that use the same lithium-ion battery technology but vary in system rating and configuration. It was found that two of the most important KPIs are response time and energy efficiency. The response time describes how fast the system can respond to changes in grid frequency. Additionally, the energy efficiency describes how effectively the system can provide energy storage during service and it can be parametrized into the efficiency of the battery, converter and transformer. The results show that all the considered LiBESS can fulfill the response time requirements of 30 seconds for FCR provision. In the future stricter requirements for the response time in grid stabilization services will most likely be required. Nevertheless, the results showed that a well configured LiBESS can provide response times on the millisecond scale. The energy efficiency evaluation showed that the system energy efficiency decreased from 89% to 85% when the power increased from 50% to 100% of rated power. At 75% of rated power it was found that the converter had the lowest efficiency (92%) based on the analysis of the efficiency of all the system components. It was also found that the power consumed by auxiliary loads was nearly constant for the examined power rates and that it significantly reduced the energy efficiency. Lastly, the battery usage analysis showed that the battery often idles or operates at low power rates if the frequency dead-band of ±10 mHz is applied around the nominal value of 50 Hz. Moreover, the battery usage can be characterized by an average State of Charge of 50% and a maximum Depth of Discharge of 30% during both charge and discharge of the batteries.

Orientador: Dr. Alfeu J. Sguarezi Filho / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2015. / Neste trabalho apresenta-se uma configuração do sistema de armazenamento de energia com baterias aplicado a sistemas de geração de energia eólica empregando conversores de fonte Z conectados à rede elétrica. Os geradores de indução gaiola de esquilo, são frequentemente utilizados nos sistemas de geração de energia eólica, por sua robustez, simplicidade, peso menor e custo baixo. Este é conectado diretamente ao conversor de potência bidirecional back to back, pode fornecer potências ativa e reativa à rede elétrica. Além disso, é estudado o conversor de fonte Z aplicado nesta topologia. No entanto, a implantação de sistemas de armazenamento de energia com baterias nos sistemas de geração de energia eólica na atualidade é muito importante, devido à possibilidade de oscilações da tensão e corrente na rede elétrica, portanto, estes podem ajudar à estabilização das tensões, correntes e a frequência na rede elétrica. Este sistema é conectado ao conversor back to back por meio de um conversor elevador-abaixador de corrente contínua. Para controlar a velocidade no eixo do rotor no gerador de indução, a estratégia é baseada no controle direto de torque. Enquanto, para o conversor do lado da rede é empregada a técnica de controle orientado pela tensão. Para o banco de baterias é utilizado o controle da tensão no barramento de corrente contínua e do fluxo na corrente da bateria, utilizando controladores do tipo PI. Com os novos desenvolvimentos tecnológicos nas chaves de potência, são apresentadas topologias de conversores CC-CA como o conversor de fonte Z, este tipo de conversor corrige algumas limitações do conversor back to back, com as características de elevador/abaixador de tensão, sem o uso de dispositivos de comutação, são permitidos os curto-circuitos na chaves, empregando novas técnicas de modulação, e reduz a quantidade harmônica injetada na rede elétrica. Os estudos foram realizados por meio de técnicas de simulação computacional usando modelos matemáticos do sistema estudado para a validação das estratégias de controle empregadas em diferentes condições de operação. Para as simulações empregou-se a ferramenta computacional SimPowerSystems R do Matlab/Simulink R . / This paper presents a battery energy storage system applied to wind power generation based on Z-source inverter connected to the power grid. The squirrel cage induction generators, often used in wind power generation systems, for its robustness, simplicity, lower weight and low cost. This is connected directly to the bidirectional power converter back to back, therefore, and provides active and reactive powers to grid. In addition, it is studied the Z-source inverter applied in this topology. However, the implementation of battery energy storage systems in wind power generation systems, currently is very important, due to possibility of the voltage and current fluctuations in the power grid, so these may to stabilisation of current, voltage and frequency on the grid. This system is connected to back to back converter through a DC-DC converter (buck-boost). For the rotor speed control on induction generator, the strategy is based on direct torque control. While, for the grid side converter is employed the technique of voltage oriented control. For the battery bank voltage control is used on DC-link voltage and battery current flow, through PI type controllers. With the new technological developments in the keys of power, DC converters topologies are presented as the Z-source inverter, this type converter fixes some limitations of the converter back to back, with the characteristics of buck-boost voltage, without the use of switching devices, allowed short-circuits on converter, using new modulation techniques, and reduces the amount injected harmonic to power grid. The studies were performed by means of computer simulation techniques using mathematical models of studied system to validate the control strategies employed in different operating conditions. For the simulations was used the computational tool SimPowerSystems R do Matlab/Simulink R .

[ES] Dos aspectos críticos en la operación de una microrred son las estrategias de control y gestión de potencia implementadas, las cuales son esenciales para proporcionar su buen funcionamiento. La aplicación adecuada de dichas estrategias permite compensar los desequilibrios de potencia causados por la discontinuidad de la generación y de la demanda de energía en las microrredes. En este sentido, el objetivo global de estas estrategias de gestión es equilibrar adecuadamente el flujo de potencia en la microrred, mediante la aplicación de diferentes algoritmos que permiten cumplir con los criterios de estabilidad, protección, balance de potencia, transiciones, sincronización con la red y gestión adecuada de la microrred. En el caso de microrredes de pequeña escala de potencia con bajo número de generadores y sistemas de almacenamiento distribuidos, las estrategias de control centralizado ofrecen un alto nivel de flexibilidad para lograr funcionalidades avanzadas en la microrred y una adecuada distribución de la potencia entre los convertidores que la conforman. Esta tesis se ha enmarcado en el contexto de algoritmos de gestión centralizada de potencia de una microrred de generación distribuida en modo conectado a red. Los algoritmos presentados se pueden aplicar a los convertidores de potencia conectados al bus DC de una microrred AC/DC híbrida o en una microrred de DC, donde el despacho de potencia es observado y gestionado por un controlador central. Este último adquiere datos del sistema mediante una infraestructura de comunicaciones y estima la potencia que gestionará cada uno de los convertidores de potencia, sistemas de almacenamiento y cargas en funcionamiento. En este estudio se muestra la validación experimental de las estrategias de gestión aplicadas en la microrred desde el enfoque del comportamiento de los convertidores de potencia, de las baterías y las cargas ante dicha gestión. Se verifica la estabilidad de la microrred sometiendo a los convertidores a diferentes escenarios de funcionamiento. Estos escenarios pueden ser fluctuaciones en la irradiación, la demanda, el estado de carga de las baterías, los límites máximos de exportación/importación de potencia desde/hacia la microrred hacia/desde la red principal y de la tarifa eléctrica. Adicionalmente, se propone un sistema de almacenamiento de energía en baterías encargado de mantener el equilibrio de potencia en el bus de DC de la microrred que permite aprovechar las fuentes de generación renovables presentes en la microrred y maximizar el tiempo de servicio de las baterías mediante la aplicación de un algoritmo de carga de las baterías. Este último se ajusta al procedimiento de carga especificado por el fabricante, estableciendo las tasas de carga en función de los escenarios en que la microrred se encuentre. El procedimiento de carga en las baterías es fundamental para garantizar las condiciones adecuadas de operación de las mismas, ya que toman en consideración los parámetros establecidos por el fabricante, como son: tasas de carga/descarga, tensión máxima de carga, temperaturas de operación, etc. / [CAT] Dos dels aspectes crítics en l'operació d'una micro-xarxa són les estratègies de control i gestió de potència implementades, les quals són essencials per proporcionar el seu bon funcionament. L'aplicació adequada de dites estratègies permet compensar els desequilibris de potència causats per la discontinuïtat de la generació i demanda d'energia en les micro-xarxes. En aquest sentit, l'objectiu global de les nomenades estratègies de gestió és equilibrar adequadament el flux de potència en la micro-xarxa mitjançant l'aplicació de diferents algoritmes que permeten complir amb els criteris d'estabilitat, protecció, balanç de potència, transicions, sincronització amb la xarxa i gestió adequada de la micro-xarxa. En el cas de micro-xarxes de potència a petita escala i amb baix nombre de generadors i sistemes d'emmagatzematge distribuïts, les estratègies de control centralitzades ofereixen un alt nivell de flexibilitat per aconseguir funcionalitats avançades en la micro-xarxa i una adequada distribució de la potència entre els convertidors que la conformen. Aquesta tesi s'ha emmarcat al context d'algoritmes de gestió centralitzada de potència d'una micro-xarxa de generació distribuïda en mode de connexió a xarxa. Els algoritmes presentats es poden aplicar als convertidors de potència connectats al bus DC d'una micro-xarxa AC/DC hibrida o en una micro-xarxa de DC, on el despatx de potència és observat i gestionat per un controlador central. Aquest últim adquireix dades del sistema mitjançant una infraestructura de comunicacions i estima la potència que gestionarà cadascun dels convertidors de potència, sistemes d'emmagatzematge i càrregues en funcionament. En aquest estudi es mostren la validació experimental de les estratègies de gestió aplicades en la micro-xarxa des d'un enfocament dels convertidors de potència, de les bateries i les càrregues davant d'aquesta gestió. Es verifica l'estabilitat de la micro-xarxa exposant als convertidors a diferents escenaris de funcionament. Aquest escenaris poden ser fluctuants en la irradiació, la demanda, l'estat de càrrega de les bateries, els límits màxims d'exportació/importació de potència des de/cap a la micro-xarxa cap a/des de la xarxa principal i de la tarifa elèctrica. Addicionalment, es proposa un sistema d'emmagatzematge d'energia en bateries encarregats de mantindre l'equilibri de potència al bus DC de la micro-xarxa i que permet aprofitar les fonts de generació renovables presents en la micro-xarxa i maximitzar el temps de servei de les bateries mitjançant l'aplicació d'un algoritme de càrrega de bateries. Aquest últim s'ajusta al procediment de càrrega especificat pel fabricant, establint les taxes de càrrega en funció dels escenaris en que la micro-xarxa es trobe. El procediment de càrrega a les bateries es fonamental per garantir les condicions adequades d'operació de les mateixes, ja que prenen en consideració els paràmetres establerts pel fabricant, com ara són: taxes de càrrega/descàrrega, tensió màxima de càrrega, temperatures d'operació, etc. / [EN] Two critical aspects in microgrids operation are the control and power management strategies, which are essential for their efficient operation. The adequate application of these strategies allows compensating the power imbalance caused by the discontinuity in the energy generation or changes in the power demand of the microgrid. In this sense, the overall objective of these power management strategies is to keep the power balance between the generation and the demand in the microgrid through the application of different algorithms that fulfill the criteria of stability, protection, smooth transitions and synchronization with the main grid. In the case of small-scale microgrids with a low number of distributed generators and energy storage systems, the centralized control strategies offer a higher level of flexibility to achieve advanced features in the microgrid and for the suitable power sharing between the converters that compose it. This thesis has been focused on centralized power management algorithms of a microgrid working in grid connected mode. These algorithms can be applied to the power converters connected to the DC bus of both hybrid AC/DC and DC microgrids, where the power dispatch is controlled by a central controller which acquires system data through a communication infrastructure and sets the power to be managed by each of the converters under operation. In this thesis, the experimental validation of the power management strategies of the microgrid is presented, from the point of view of the behavior of the power converters, batteries and loads. It is provided with a realistic evaluation under different microgrid operation scenarios. These scenarios were sudden changes of the irradiation, load, state of charge, the maximum power to be exported/imported from/to the microgrid to/from the grid, and the electricity tariff. Additionally, it is proposed a battery energy storage system that keeps the power balance at the DC bus of the microgrid, taking advantage from the renewable energy sources and adjusting the battery energy storage through a suitable charging procedure specified by the manufacturer. The proposed procedure changes the charging parameters of the batteries depending on the microgrid states. Its goal is to extend the service time of batteries and to allow proper energy management in the system. / Salas Puente, RA. (2019). Gestión eficiente de los convertidores de potencia conectados al bus DC de una Microrred híbrida de generación distribuida [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/118658 / TESIS

Research has shown that three-phase balancing alone can improve the operation of secondary distribution networks and that the addition of energy storage to the phase balancing power electronics further helps to alleviate the negative effects of phase unbalances. However, less attention has been paid to the economic potential of said technologies and particularly for loadside implementation. It appears that the deployment of phase balancers, with or without energy storage, is indeed hampered by uncertainty related to its economic feasibility, despite both technologies being commercially available. This thesis therefore aims to assess and compare the economic feasibility of the two configurations for peak shaving purposes in the context of residential property loads in Sweden. The assessment was performed using a specially developed deterministic techno-economic model taking into consideration historical load data from three Swedish real estate, cost estimations for a range of alternatives used when sizing the systems, applicable tariffs and fees for electricity and its distribution as well as technical parameters such as the capacities and efficiencies of the involved components. A novel approach was taken by linearly extrapolating the three load profiles into three sets of 91 synthesized load profiles to enable a larger dataset for analysis. The net present values generated for each set were then graphed and analyzed per original real estate. The results showed that both configurations can be economically feasible, but only under certain conditions. A phase balancer alone was found to be feasible for real estate whose peak currents are distinctly unbalanced and exceed 50 A, with the best expected rate of return for profiles exceeding 63 A since they enable a tariff switch. The combined system was found to be even more contingent on the tariff switch and therefore only feasible for peaks above 63 A. A substantial difference in the initial investment further makes the single phase balancer the preferred choice, unless the discount rate is as low as 2 % or less. On this basis, potential investors need to assess the state of unbalance of their loads and perform their own calculation based their load profile, cost of capital and applicable tariffs. / Tidigare forskning har visat att fasbalansering enskilt kan förbättra driften hos lokala distributionsnät och att ett batterisystem i tillägg till fasbalanserarens kraftelektronik ytterligare kan minska de negativa effekterna av fasobalanser. Däremot har mindre uppmärksamhet riktats mot den ekonomiska genomförbarheten hos dessa teknologier och i synnerhet för implementation på lastens sida av elmätaren. Det tycks vara så att spridningen av fasbalanserare, med eller utan energilagring, hindras av osäkerheten kring dess ekonomiska potential trots att båda teknologierna är kommersiellt tillgängliga. Detta arbete ämnar därför att värdera och jämföra den ekonomiska nyttan hos de två konfigurationerna vid toppreducering av fastighetselen i svenska bostadsfastigheter. Värderingen utfördes med hjälp av en särskilt utvecklad deterministisk tekno-ekonomisk modell som beaktade historiska lastdata från tre svenska fastigheter, kostnadsuppskattningar för en uppsättning av konfigurationer som användes vid dimensionering av systemen, applicerbara tariffer och avgifter för elektricitet och dess distribution samt tekniska parametrar såsom kapaciteter och verkningsgrader för de olika komponenterna. Ett annorlunda tillvägagångssätt tillämpades vidare för att utöka datamängden genom linjär extrapolation av lastprofilerna, vilket resulterade i tre uppsättningar av 91 syntetiserade lastprofiler. Nettonuvärdet beräknades följaktligen för varje profil och investeringsalternativ för att sedan plottas och analyseras per ursprunglig fastighet. Resultaten visade att båda konfigurationerna kan uppvisa lönsamhet, men endast under särskilda förutsättningar. Den enskilda fasbalanseraren bedömdes som lönsam för fastigheter vars strömtoppar är påtagligt obalanserade och som överstiger 50 A, med största möjliga lönsamhet för profiler som överstiger 63 A då dessa möjliggör ett tariffbyte. Det kombinerade systemets lönsamhet bedömdes vara ännu mer beroende av tariffbytet och därför endast lönsamt för strömtoppar över 63 A. En betydligt större grundinvestering för det kombinerade systemet gör vidare att den enskilda fasbalanseraren i regel är att föredra, såvida inte kalkylräntan är så låg som 2 % eller mindre. Baserat på detta uppmanas potentiella investerare att undersöka balanstillståndet hos deras laster och att utföra en egen kalkyl baserat på deras specifika last, kapitalkostnad och nätföretag.