No description available.

The building sector contributes substantial energy consumption and greenhouse gas (GHG) emissions. Energy efficiency is the main driver for the mitigation of climate change. Schools are placed with high energy consumption and GHG emitting. Most of the existing schools in Europe and Sweden need to be renovated by considering the environmental impacts and energy consumption. Most of the traditional retrofitting techniques have not been evaluated for environmental impacts as well as energy-saving. The project aims to conduct an environmental impact assessment for energy retrofitting options for the school building. Energy simulation and life cycle assessment (LCA) techniques are employed to achieve this target. IDA-ICE and SimaPro programs are used to simulate the retrofitting methods. Celsius high school in Uppsala is selected as a model to study LCA for retrofitting solutions. The retrofitting techniques are focused on three aspects, the demand-side aspect to reduce energy demand in buildings (thermal insulation and ventilation system operation), the supply-side aspect that uses a renewable energy source (solar photovoltaic), and energy consumption patterns (ventilation and lighting time according to schedule of the school days). Firstly, an energy simulation was conducted by IDA-ICE for retrofitting solutions. Adding insulation materials (Cellulose & Glass wool) to the external walls and roof, changing the ventilation operation, from continuous to variable air volume, and installation of photovoltaic panels (PV), caused the energy to be reduced from 142 kWh/m2 to 97 kWh/ m2, with efficiency 32 percent. By the retrofitting methods, the district heating energy is decreased from 87.3 kWh/m2 to 68.8 kWh/m2 and electrical energy is reduced from 54.2 kWh/m2 to 27.8 kWh/m2. Installation of PV on the roof by this area (161 m2) can be produced electrical energy of about 1.5 kWh/m2. Secondly, is conducted life cycle assessment (LCA) for all the proposed retrofitting solutions by the SimaPro program. The system boundary included manufacturing and operation (cradle to operation) and demolition and end-of-life phase are excluded from the system boundary. Functional unit is the operation of the building during during 40 years at Celsius school in Uppsala. The assumption is the retrofitting materials are produced and transport in Sweden. Vattenfall is the supplier of the electrical and heating energy for Celsius school in Uppsala. The most percent of primary energy are waste solid. LCA is presented the retrofitting is decreased the GHG and some of the environmental impact categories. / Byggsektorn bidrar med betydande energiförbrukning och utsläpp av växthusgaser (GHG). Energieffektivitet är den främsta drivkraften för att mildra klimatförändringarna. Skolor är placerade med hög energiförbrukning och utsläpp av växthusgaser. De flesta av de befintliga skolorna i Europa och Sverige behöver renoveras med hänsyn till miljöpåverkan och energiförbrukning. De flesta av de traditionella eftermonteringsteknikerna har inte utvärderats för miljöpåverkan eller energibesparing. Projektet syftar till att göra en miljökonsekvensbeskrivning för alternativ för energirenovering av skolbyggnaden. Tekniker för energisimulering och livscykelbedömning (LCA) används för att uppnå detta mål. IDA-ICE och SimaPro-programmen används för att simulera eftermonteringsmetoderna. Celsiusgymnasiet i Uppsala väljs ut som modell för att studera LCA för eftermonteringslösningar. Eftermonteringsteknikerna är fokuserade på tre aspekter, aspekten på efterfrågesidan för att minska energibehovet i byggnader (värmeisolering och drift av ventilationssystem), aspekten på utbudssidan som använder en förnybar energikälla (solcellsenergi) och energiförbrukningsmönster ( ventilation och belysningstid enligt skoldagarnas schema). Först genomfördes en energisimulering av IDA-ICE för eftermontering av lösningar. Att lägga till isoleringsmaterial (cellulosa och glasull) till ytterväggar och tak, ändra ventilationsdrift, från kontinuerlig till variabel luftvolym, och installation av solcellspaneler (PV), gjorde att energin minskade från 142 kWh/m2 till 97 kWh/m2, med verkningsgrad 32 procent. Genom eftermonteringsmetoderna sänks fjärrvärmeenergin från 87,3 kWh/m2 till 68,8 kWh/m2 och elenergin minskas från 54,2 kWh/m2 till 27,8 kWh/m2. Installation av PV på taket vid detta område (161 m2) kan producera elektrisk energi på cirka 1,5 kWh/m2. För det andra genomförs livscykelanalys (LCA) för alla föreslagna eftermonteringslösningar av SimaPro-programmet. Systemgränsen inkluderade tillverkning och drift (vagga till drift) och rivnings- och uttjänt fas är exkluderade från systemgränsen. Funktionell enhet är driften av byggnaden under 40 år på Celsiusskolan i Uppsala. Antagandet är att eftermonteringsmaterialen tillverkas och transporteras i Sverige. Vattenfall är leverantör av el- och värmeenergin till Celsiusskolan i Uppsala. Den största delen av primärenergin är fast avfall. LCA presenteras eftermonteringen minskar GHG och några av miljöpåverkanskategorierna.

<p>Systemic Acquired Resistance (SAR) is a plant defense response induced by an initial infection in one part of the plant that leads to broad-spectrum resistance to normally virulent pathogens in distant naïve leaves. As part of the Cameron research team, I contributed to demonstrating that the lipid transfer protein, DIR1 is required for SAR long distance signaling in <em>Arabidopsis</em> and travels from induced to distant tissues during SAR. A highly similar<em> Arabidopsis</em> protein DIR1-like was identified and is thought to be responsible for the occasional SAR-competent phenotype observed in the <em>dir1-1</em> mutant. This work provides evidence for the idea that DIR1 and DIR1-like are paralogs created by a recent duplication event and that similar to DIR1, DIR1-like may travel to distant tissues during SAR. To better understand DIR1 and DIR1-like contribution during SAR, <em>dir1-1dir1-like</em> double mutant transgenic plants were created as well as transgenic plants expressing epitope- (HA and FLAG) and fluorescent- (iLOV and phiLOV) tagged DIR1 and DIR1-like to facilitate visualization of movement during SAR. Several putative DIR1 orthologs were identified in crop plants and cucumber CucDIR1 was shown to be functionally equivalent to AtDIR1 in <em>dir1-1</em> complementation studies providing further evidence that DIR1 plays an important role in SAR across plant species. By analyzing conservation between DIR1, DIR1-like and the putative DIR1 orthologs, several protein residues were identified that may be important for DIR1 function during SAR. DIR1 proteins were modified at these sites and the importance of these residues was supported by the reduced binding of the TNS hydrophobic probe in these DIR1 variants. Taken together, this thesis suggests that DIR1 and DIR1-like both participate in SAR in <em>Arabidopsis</em>, that DIR1 crop orthologs are also important for the SAR response and that DIR1 possesses several sites that are critical for its function in long distance SAR signaling.</p> / Doctor of Philosophy (PhD)

As a response to the increasing demand for renewable power, the solar photovoltaic (PV) market is growing fast. In addition to PV systems, the energy from solar radiation can be converted intoheat energy in solar thermal (ST) systems. This study uses a method that identifies solar energy systems using aerial imagery and deep machine learning to create and evaluate an inventory of solar energy systems in three Swedish municipalities together with socioeconomic and demographic data, to understand the relation between different variables and PV and ST adoption. The variables are age, sex, birth region, education, unemployment, average income and economic standard. Information about the locations also include owner, time at residence, tax value, purpose of property and purpose of building. The relation is analyzed through a correlation and regression analysis at three different granularity levels: households, demographic statistical areas and municipalities. Out of 692 inventoried PV systems and 399 ST systems, the majority was installed in rural or regional center areas. The most common buildings were residential and complementary. Most of the properties were owned by individuals, and the tax value of properties was in general lower for ST systems, indicating that it is more common for companies to install PV systems and at larger properties. The average income, age and percentage of males are higher for households that have adopted PV and/or ST systems compared to the municipalities average. However, the difference is clearer for PV systems than for ST systems. The analysis concludes that share of the population in age group 45-64 years, share of males, share born in Sweden and high average income have a positive correlation to PV adoption. Share of the population within age group 25-44 years, unemployment and low economic standard isfound to have a negative correlation to PV deployment. Positive correlation to ST adoption is found for a share of the population within age group 45-64 years and born in Sweden. Share of population in age group 24-44 years and unemployment was found to have a negative correlation to ST deployment.

No description available.

A single-phase grid connected transformerless photovoltaic (PV) inverter for residential application is presented. The inverter is derived from a boost cascaded with buck converter along with a line frequency unfolding circuit. Due to its novel operating modes, high efficiency can be achieved because there is only one switch operating at high frequency at a time, and the converter allows the use of power MOSFET and ultra-fast reverse recovery diode. This dissertation begins with theoretical analysis and modeling of this boost-buck converter based inverter. And the model indicates small boost inductance will leads to increase the resonant pole frequency and decrease the peak of Q, which help the system be controlled easier and more stable. Thus, interleaved multiple phases structure is proposed to have small equivalent inductance, meanwhile the ripple can be decreased, and the inductor size can be reduced as well. A two-phase interleaved inverter is then designed accordingly. The double-carrier modulation method is proposed based on the inverter's operation mode. The duty cycle for buck switch is always one if the inverter is running in boost mode. And the duty cycle for boost switches are always zero if the inverter is running in buck mode. Because of this, the carrier for boost mode is stacked on the top of the carrier for buck mode, as a result, there is no need to compare the input and output voltage to decide which mode the inverter should operate in. And the inverter operates smoothly between these two modes. Based on similar concept, three advanced modulation methods are proposed. One of them can help further improve the efficiency, and one of them can help increase the bandwidth and gain, and the last one takes the advantage of both. Based on similar concept, another three dual-mode double-carrier based SPWM inverters are proposed. With both step-up and step-down functions, this type of inverter can achieve high efficiency in a wide range because only one switch operates at the PWM frequency at a time. Finally, the simulation and experiment results are shown to verify the concept and the tested CEC (California Energy Commission) efficiency is 97.4%. It performs up to 2% more efficiently better than the conventional solution. / Ph. D.

With development of renewable energies worldwide, power system is seeing higher penetration of Utility-scale photovoltaic (PV) farms at distributed level as well as transmission level. Power electronics converters present negative incremental impedance characteristics at their input while under regulated output control, which brings in the possibility of system instability. Recent evidence suggests that large-scale penetration of PV inverters increases the probability of instability. While IEEE standard 1547 newest version requires PV inverters to have reactive power control, there have been few investigations into the small-signal stability impact of PV inverters on distribution systems especially with reactive power control. In addition, the existing studies either use the conventional way of state space equations and eigenvalues or use time-domain simulation methodology, which are based on the assumptions that detailed models of the grid and the PV inverters are accessible. Different from the previous literatures, this research employs Generalized Nyquist Criterion (GNC) method based on measured impedances in d-q frames at connection interfaces. GNC method has the advantage that interconnection stability can be judged without knowing the grid and PV generator model details. This work first demonstrates the advantage of volt-var droop mode control among all different local reactive power control modes for PV inverters in the aspects of static impact on grid voltage profiles and power loss in a 12kV test-bed distribution system. Then it is discovered that d-q frame impedance of PV inverter under volt-var droop mode control shows a significant difference from other reactive power control modes. The d-q frame impedance derived from the small-signal model of PV generator is validated by both MATLAB simulation results and hardware experiments. Based on the d-q frame impedances, GNC is utilized to analyze the stability connection of a single PV farm and multiple PVs into the grid. GNC stability assessment results match with time-domain simulations and reveal the stability problem related to volt-var droop mode control. Furthermore, considering the unbalance of the distribution system, a new impedance model in d-q frame is proposed to capture both the dynamics of PV inverter operating in unbalanced points and the dynamics of three-phase unbalanced grid. The new impedance model is a combination of positive-negative sequence impedance and conventional d-q frame impedance. A procedure is designed for the measurement of the extended d-q frame impedance and the GNC application to predict small-signal stability of the unbalanced grid, which are justified by both time domain simulation and hardware experiments. / Doctor of Philosophy / To overcome the limited fossil fuel reserve on the earth and global warming, renewable energies become more and more popular worldwide. Centralized thermal power generators in the transmission system are gradually being replaced by distributed energy resources (DER) which are connection to the distribution system, bringing more challenges to the safe and stable operation of the power system. This work focuses on the small-signal stability impact of photovoltaic (PV) generators in the distribution system, which basically analyzes into whether the connection of PV generator to the distribution system will end up in an expected steady operation state with high resistance to any relatively small disturbances. The stability assessment tool is based on impedance measurement which treats both sides as black boxes and bridges the information gap between Utility operators and PV generator vendors. A major finding of this work is that while PV generators in the distribution system help to provide grid-support functions of voltage regulation, they may cause voltage small-signal stability problems due to the high grid impedance, which is worse if more PV inverters are put in parallel. Even PV farms connected to different branches of the complicated radial distribution system may have interactions with each other. So the design of control strategy and parameters of PV generator should consider the impact of other PV generators. GNC method based on impedances measurement is feasible and accurate for stability assessment of a distribution system with multiple PV farms. The impedance based method is upgraded and extended to be applied for the connection of power electronics devices to the three-phase unbalanced distribution systems.

Tesis por compendio / Xanthomonas arboricola pv. pruni is the causal agent of the bacterial spot disease of stone fruits, almond and ornamental species of Prunus. This pathogen constitutes one of the major threats to this group of species due to the economic losses it generates, and it is therefore considered as a quarantine organism in the European Union (EU). Recently, several outbreaks of the disease have been described in EU countries including Spain, where this pathogen has been detected in seven regions. Given the importance of this emerging disease and the lack of information about it, several aspects related to its diagnosis and epidemiology have been addressed in this work. Additionally, taxonomic characterization of three atypical Xanthomonas strains isolated from nectarines, causing similar symptoms to those produced by X. arboricola pv. pruni, have also been performed. First, a prototype of lateral flow immunoassay has been designed for the diagnosis of bacterial spot disease. It was developed by producing two polyclonal antibodies which were then combined with carbon nanoparticles and assembled on nitrocellulose strips. The specificity of the immunoassay was tested, obtaining a positive result with all the strains of X. arboricola pv. pruni analyzed. The limit of detection observed was 104 CFU/ml, which is sufficient for the detection of this pathogen in symptomatic samples. To demonstrate the accuracy and the reliability of the immunoassay, the prototype developed was used in the analysis of naturally infected field samples and healthy samples. Results were compared to those obtained by plate isolation and real time PCR, and a high correlation among techniques was observed. In a second step, as X. arboricola pv. pruni was first detected in Spain in 2002, and in subsequent years several outbreaks have occurred in 11 provinces, it was considered of interest to study the relationships between a collection of 239 Spanish strains of this pathogen originated from nurseries, orchards and interceptions with the technique of the Multilocus Variable Number of Tandem Repeat Analysis (MLVA). This method confirmed its high discriminatory power and the strains were grouped in 18 genetic clusters. The results obtained suggest multiple introductions of X. arboricola pv. pruni in Spain, and the leading role of the nurseries in the introduction and dissemination of this pathogen through the commercialization of contaminated plant propagation material. Finally, three strains isolated from nectarines in Murcia showing similar symptoms to those produced by X. arboricola pv. pruni, were analyzed using both phenotypic and molecular methods. The first results of biochemical tests and PCR were negative for this pathogen. Therefore, these isolates have been subjected to a taxonomic characterization through a polyphasic approach, comparing them with reference strains of other Xanthomonas species. Additionally, inoculations on peach plants demonstrated the pathogenicity of the three strains. The results obtained confirmed that these strains constitute a new species of the genus Xanthomonas, for which the name Xanthomonas prunicola has been proposed, and its main differential characteristics from the other species of this genus have been defined. Overall, the studies collected in this thesis provide a rapid method for on-site diagnosis of the bacterial spot disease, a deeper knowledge of the genetic diversity of the Spanish strains of X. arboricola pv. pruni and the development of a new methodology for its evaluation, as well as the description of a new Xanthomonas species that affects nectarine. / Xanthomonas arboricola pv. pruni es el agente causal de la mancha bacteriana de los frutales de hueso, el almendro y especies ornamentales del género Prunus. Este patógeno constituye una de las mayores amenazas para estas especies debido a las pérdidas económicas que genera, por lo que está considerado como un organismo de cuarentena en la Unión Europea (UE). Se han descrito numerosos brotes en países miembros de la UE en los últimos años y entre ellos en España, donde ha sido detectada la bacteria en siete Comunidades Autónomas. Ante la importancia de esta enfermedad emergente y la carencia de información sobre la misma, en este trabajo se han abordado aspectos relacionados con su diagnóstico y epidemiología que permitirán ampliar nuestro conocimiento sobre ella. Además, también se ha realizado la caracterización taxonómica de tres cepas atípicas de Xanthomonas aisladas de nectarino, que causan síntomas similares a los producidos por X. arboricola pv. pruni. En primer lugar, se ha desarrollado un prototipo de tiras inmunológicas de flujo lateral para el diagnóstico de la mancha bacteriana. Para su diseño, se partió de dos anticuerpos policlonales que se combinaron con nanopartículas de carbono y se ensamblaron en membranas de nitrocelulosa. Se analizó la especificidad de las tiras, obteniendo resultado positivo con todas las cepas de X. arboricola pv. pruni ensayadas. El límite de detección obtenido con las tiras de flujo lateral fue de 104 UFC/ml, que es suficiente para la detección de esta bacteria en muestras sintomáticas. Para comprobar su fiabilidad y precisión, el prototipo desarrollado se utilizó en el análisis de muestras de campo naturalmente infectadas y muestras sanas, y los resultados se compararon con los obtenidos en el aislamiento en medio de cultivo y los de PCR en tiempo real, observándose una elevada correlación entre las tres técnicas. En segundo lugar, como X. arboricola pv. pruni se detectó por primera vez en España en 2002, y desde entonces se han producido brotes de la enfermedad en 11 provincias, se consideró de interés estudiar las relaciones existentes entre una colección de 239 cepas españolas de esta bacteria procedentes de viveros, plantaciones e intercepciones, con la técnica del "Multilocus Variable Number of Tandem Repeat Analysis" (MLVA). Se demostró su gran poder de resolución ya que permitió clasificar las cepas en 18 grupos genéticos. Los resultados obtenidos sugieren que en España se han producido múltiples introducciones de la bacteria, y que los viveros han jugado un papel importante en la introducción y diseminación del patógeno a través de la comercialización de material vegetal contaminado. Por último, se analizaron fenotípica y molecularmente tres cepas aisladas en nectarinos de la provincia de Murcia, que mostraban síntomas similares a los causados por X. arboricola pv. pruni. Los primeros análisis basados en test bioquímicos y PCR resultaron negativos para este patógeno. Por tanto, se ha llevado a cabo la caracterización taxonómica de dichos aislados a través de un estudio polifásico, comparándolos con cepas de referencia de otras especies de Xanthomonas. Además, se realizaron inoculaciones que confirmaron la patogenicidad de las cepas. Los resultados obtenidos han permitido clasificar estas cepas como una nueva especie del género Xanthomonas, para la que se ha propuesto el nombre de Xanthomonas prunicola y para la que se han definido sus características diferenciales de las otras especies de este género. Los trabajos presentados en esta memoria han aportado un nuevo método rápido de diagnóstico in situ de la mancha bacteriana, el desarrollo una nueva metodología para la evaluación de la diversidad genética de una selección de cepas españolas de X. arboricola pv. pruni, así como la descripción de una nueva especie de Xanthomonas que afecta a nectarino. / Xanthomonas arboricola pv. pruni és l'agent causal de la taca bacteriana dels fruiters d'os, l'ametler i espècies ornamentals del gènere Prunus. Aquest patogen constitueix una de les majors amenaces per a aquestes espècies a causa de les pèrdues econòmiques que genera, per la qual cosa està considerat com un organisme de quarantena en la Unió Europea (UE). S'han descrit nombrosos brots en països membres de la UE en els últims anys i entre ells a Espanya, on ha sigut detectat el bacteri en set Comunitats Autònomes. Davant la importància d'aquesta malaltia emergent i la manca d'informació sobre aquest tema, en aquest treball s¿han abordat aspectos relacionats amb el seu diagnòstic i epidemiologia que permetran ampliar el nostre coneixement sobre ella. A més, també s'ha realitzat la caracterització taxonòmica de tres ceps atípics de Xanthomonas aïllats de nectariner, que causen símptomes similars als produïts per X. arboricola pv. pruni. En primer lloc, s'ha desenvolupat un prototip de tires immunològiques de flux lateral per al diagnòstic de la taca bacteriana. Per al seu disseny, es va partir de dos anticossos policlonals que es van combinar amb nanopartícules de carboni i es van assemblar en membranes de nitrocel¿lulosa. Es va analitzar l'especificitat de les tires obtenint resultat positiu amb tots els ceps de X. arboricola pv. pruni assajats. El límit de detecció obtingut amb les tires de flux lateral va ser de 104 UFC/ml, que és suficient per a la detecció d'aquest bacteri en mostres amb símptomes de la malaltia. Per a comprovar la seua fiabilitat i precisió, el prototip desenvolupat es va utilitzar en l'anàlisi de mostres de camp naturalment infectades i mostres sanes, i els resultats es van comparar amb els obtinguts en l'aïllament en medi de cultiu i els de PCR en temps real, observant-se una elevada correlació entre les tres tècniques. En segon lloc, com que X. arboricola pv. pruni es va detectar per primera vegada a Espanya en 2002, i des de llavors s¿han produït brots de la malaltia en 11 províncies, es va considerar d'interès estudiar les relacions existents entre una col¿lecció de 239 ceps espanyols d'aquest bacteri procedents de vivers, plantacions i intercepcions amb la tècnica del "Multilocus Variable Number of Tandem Repeat Analysis" (MLVA). Es va demostrar el seu gran poder de resolució ja que va permetre classificar els ceps en 18 grups genètics. Els resultats obtinguts suggereixen que a Espanya s'han produït múltiples introduccions del bacteri, i que els vivers han jugat un paper important en la introducció i disseminació del patogen a través de material vegetal contaminat. Finalment, es van analitzar fenotípicament i molecularment tres ceps aïllats en nectariners de la província de Múrcia, que mostraven símptomes similars als causats per X. arboricola pv. pruni. Les primeres anàlisis basades en test bioquímics i PCR van resultar negatius per a aquest patogen. Per tant, s'ha dut a terme la caracterització taxonòmica de dits aïllats a través d'un estudi polifàsic, comparant aquests amb ceps de referència d'altres espècies de Xanthomonas. A més, es van realitzar inoculacions que van confirmar la patogenicitat dels ceps. Els resultats obtinguts han permés classificar aquests ceps com una nova espècie del gènere Xanthomonas, per a la qual s'ha proposat el nom de Xanthomonas prunicola, i per a la que s'han definit les seues característiques diferencials de les altres espècies d'aquest génere. Els treballs presentats en aquesta memoria han aportat un nou mètode ràpid de diagnòstic in situ de la taca bacteriana, el desenvolupament d'una nova metodologia per a l'avaluació de la diversitat genètica d'una selecció de ceps espanyols de X. arboricola pv. pruni, així com la descripció d'una nova espècie de Xanthomonas que afecta al nectariner. / López Soriano, P. (2017). Especies de Xanthomonas causantes de enfermedades en frutales de hueso y almendro: diagnóstico, diversidad genética y taxonomía [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/86200 / Compendio

Yes / This paper proposes a probabilistic multi-objective optimization method for the operation of three-phase distribution networks incorporating active network management (ANM) schemes including coordinated voltage control and adaptive power factor control. The proposed probabilistic method incorporates detailed modelling of three-phase distribution network components and considers different operational objectives. The method simultaneously minimizes the total energy losses of the lines from the point of view of distribution network operators (DNOs) and maximizes the energy generated by photovoltaic (PV) cells considering ANM schemes and network constraints. Uncertainties related to intermittent generation of PVs and load demands are modelled by probability density functions (PDFs). Monte Carlo simulation method is employed to use the generated PDFs. The problem is solved using ɛ-constraint approach and fuzzy satisfying method is used to select the best solution from the Pareto optimal set. The effectiveness of the proposed probabilistic method is demonstrated with IEEE 13- and 34- bus test feeders.

The penetration of renewable and distributed generation sources (DGs) in power distribution systems has been increasing at an ever-faster rate. While DGs provide clean and affordable energy, their addition introduces new problems in the system operation. One of the main challenges due to the high penetration of DGs is the overvoltage issues that demand appropriate voltage control. This control is essential to maintain the power quality, energy efficiency, and voltage stability in the system. Voltage Regulators (VRs) and capacitor banks (CBs) are traditional control devices that are installed in the system to keep the desired voltage profile. However, they are not designed to operate in a way that can address the high frequency and magnitude changes occurring in systems with high penetration of DGs. Therefore, they need to be supplemented with voltage control performed by controlling the reactive power generation of the DGs. The coordination among these different control devices is essential for proper system operation. This thesis explores the design of the coordinated control of VRs, CBs, and DGs, by considering different control methods such as coordinated cooperative, predictive cooperative, and unified control of all voltage control devices. The proposed methods are implemented in a system with high penetration of DGs and tested by exploring the worst-case scenario in terms of DG sizing and placement. This scenario is determined analytically using sensitivities and verified using stochastic Monte Carlo simulation. The future generation of active power distribution systems need to be optimally controlled in order to be efficient, reliable, and resilient, while capable of effectively managing high penetration levels of DGs, and other controllable loads and devices. The important outcome of this thesis is the introduction of a practical voltage control method to achieve these goals.