Enhanced Electric Vehicle Integration in the UK Low Voltage Networks with Distributed Phase Shifting Control

Electric vehicles (EV) have gained global attention due to increasing oil prices and rising concerns about transportation-related urban air pollution and climate change. While mass adoption of EVs has several economic and environmental benefits, large-scale deployment of EVs on the low-voltage (LV) urban distribution networks will also result in technical challenges. This paper proposes a simple and easy to implement single-phase EV charging coordination strategy with three-phase network supply, in which chargers connect EVs to the less loaded phase of their feeder at the beginning of the charging process. Hence, network unbalance is mitigated and, as a result, EV hosting capacity is increased. A new concept, called Maximum EV Hosting Capacity (HC max) of low voltage distribution networks, is introduced to objectively assess and quantify the enhancement that the proposed phase-shifting strategy could bring to distribution networks. The resulting performance improvement has been demonstrated over three real UK residential networks through a comprehensive Monte Carlo simulation study using Matlab and OpenDSS tools. With the same EV penetration level, the under-voltage probability was reduced in the first network from 100% to 54% and in the second network from 100% to 48%. Furthermore, percentage voltage unbalance factors in the networks were successfully restored to their original values before any EV connection.Peer reviewedFinal Accepted Versio

New phase-changing soft open point and impacts on optimising unbalanced power distribution networks

Three-phase unbalanced conditions in distribution networks are conventionally caused by load imbalance, asymmetrical fault conditions of transformers and impedances of three phases. The uneven integration of single-phase distributed generation (DG) worsens the imbalance situation. These unbalanced conditions result in financial losses, inefficient utilisation of assets and security risks to the network infrastructure. In this study, a phase-changing soft open point (PC-SOP) is proposed as a new way of connecting soft open points (SOPs) to balance the power flows among three phases by controlling active power and reactive power. Then an operational strategy based on PC-SOPs is presented for three-phase four-wire unbalanced systems. By optimising the regulation of SOPs, optimal energy storage systems dispatch and DG curtailment, the proposed strategy can reduce power losses and three-phase imbalance. Second-order cone programming (SOCP) relaxation is utilised to convert the original non-convex and non-linear model into an SOCP model which can be solved efficiently by commercial solvers. Case studies are conducted on a modified IEEE 34-node three-phase four-wire system and the IEEE 123-node test feeder to verify the effectiveness, efficiency and scalability of the proposed PC-SOP concept and its operational strategy

Transaction-Oriented Dynamic Power Flow Tracing for Distribution Networks – Definition and Implementation in GIS Environment

There is a growing interest from owners of distributed energy resources (DERs) to actively participate in the energy market through peer-to-peer (P2P) energy trading. Many strategies have been proposed to base P2P energy trading on. However, in those schemes neither the costs of assets usage nor the losses incurred are so far taken into account. This article presents a transaction-oriented dynamic power flow tracing (PFT) platform for distribution networks (DNs) implemented in a geographic information system (GIS) environment. It introduces a new transaction model that quantifies the use of the DN, apportions the losses and unlocks a flexible use of the surplus generation enabling that prosumers can adopt simultaneously different mechanisms for participation in energy trading, maximizing renewable energy usage. The platform is also helpful for future distribution system operators (DSOs) to overcome the status invisibility of low voltage (LV) DNs, determine who makes use of the assets, debit the losses on them and explore the effects from new connections. A case study is conducted over the IEEE European LV Test Feeder. The tool provides a clear, intuitive, temporal and spatial assessment of the network operation and the resulting power transactions, including losses share and efficiency of DERs

Fuzzy inference system for integrated VVC in isolated power systems

This paper presents a fuzzy inference system for integrated volt/var control (VVC) in distribution substations. The purpose is go forward to automation distribution applying conservation voltage reduction (CVR) in isolated power systems where control capabilities are limited. A fuzzy controller has been designed. Working as an on-line tool, it has been tested under real conditions and it has managed the operation during a whole day in a distribution substation. Within the limits of control capabilities of the system, the controller maintained successfully an acceptable voltage profile, power factor values over 0,98 and it has ostensibly improved the performance given by an optimal power flow based automation system. CVR savings during the test are evaluated and the aim to integrate it in the VVC is presented.Comment: arXiv admin note: substantial text overlap with arXiv:1401.163

Multi-criteria decision making monarch butterfly optimization for optimal distributed energy resources mix in distribution networks

The optimal integration of distributed energy resources (DERs) is a multiobjective and complex combinatorial optimization problem that conventional optimization methods cannot solve efficiently. This paper reviews the existing DER integration models, optimization and multi-criteria decision-making approaches. Further to that, a recently developed monarch butterfly optimization method is introduced to solve the problem of DER mix in distribution systems. A new multiobjective DER integration problem is formulated to find the optimal sites, sizes and mix (dispatchable and non-dispatchable) for DERs considering multiple key performance objectives. Besides, a hybrid method that combines the monarch butterfly optimization and the technique for order of preference by similarity to ideal solution (TOPSIS) is proposed to solve the formulated large-scale multi-criteria decision-making problem. Whilst the meta-heuristic optimization method generates non-dominated solutions (creating Pareto-front), the TOPSIS approach selects that with the most promising outcome from a large number of alternatives. The effectiveness of this approach is verified by solving single and multiobjective dispatchable DER integration problems over the benchmark 33-bus distribution system and the performance is compared with the existing optimization methods. The proposed model of DER mix and the optimization technique significantly improve the system performance in terms of average annual energy loss reduction by 78.36%, mean node voltage deviation improvement by 9.59% and average branches loadability limits enhancement by 50%, and minimized the power fluctuation induced by 48.39% renewable penetration. The proposed optimization techniques outperform the existing methods with promising exploration and exploitation abilities to solve engineering optimization problems

Prevalencia de alteraciones posturales de cabeza-cuello y hombro en personas adultas oficinistas con una carga horaria continua en posición sedente

Tesis (Kinesiólogo)El presente estudio tiene como objetivos la determinación de la prevalencia de alteraciones posturales, enfocadas en la región de cabeza, cuello y hombros, en personas adultas que se desempeñan laboralmente como oficinistas, y relacionar los datos encontrados con la prevalencia de síntomas y/o enfermedad músculo-esquelética. El método de trabajo incluye la evaluación postural a través de la fotogrametría, donde se tomaron fotografías de los sujetos evaluados en su puesto de trabajo en los planos anterior, posterior y sagital, siguiendo de una recolección de datos respecto a síntomas y enfermedades a través de la aplicación de encuesta, y posterior a ello se realizó el análisis de los datos obtenidos mediante el uso del software estadístico SPSS. Los resultados demuestran que el 100% de la muestra presentó alguna de las cinco alteraciones posturales evaluadas, las cuales fueron anteposición de cabeza-cuello, inclinación de cabeza, antepulsión de hombros, elevación/descenso de hombros. De todas las alteraciones evaluadas, la mayor prevalencia se encontró en la anteposición de cabeza-cuello, lo cual es posible de atribuir al trabajo desempeña por los oficinistas y la postura que adquieren al utilizar un computador durante un tiempo prolongado

Multi-terminal phase-changing soft open point SDP modeling for imbalance mitigation in active distribution networks

Active distribution networks (ADNs) are capable of mitigating phase imbalance caused by various operational conditions, including uneven growth of single-phase and intermittent distributed energy resources (DERs), incurring financial losses or costly infrastructure reinforcements. In this paper, the research gap for a flexible phase imbalance mitigating solution is addressed by proposing a multi-terminal phase-changing soft open point (PC-SOP). It is explored in detail on balancing the power flows and compared with other different types and ways of connection (including two-terminal and conventional). Then operational strategies based on different cases are presented for imbalance mitigation. Semidefinite programming (SDP) relaxation is utilized to convert the original non-convex nonlinear model into an SDP model which can be solved efficiently by commercial solvers. Two case studies demonstrations are conducted on IEEE 13-node and 123-node three-phase networks. It is found that multi-terminal PC-SOPs can minimize power losses by between 5.56 % and 28.98% and have better voltage control (all buses operate in the allowed voltage range [0.94, 1.10]) and less PV curtailment (reduced by at least 6.31 MW/24 h and 0.63 MW/24 h for the two test networks separately) when compared to conventional SOP technologies

Efectividad del extracto de Neem (Azadirachta indica Juss) NEEMX sobre el pulgon verde del duraznero (Myzus persicae S.), en pimenton (Capsicum annum var. grossum) bajo condiciones de invernadero

Resumen (Spanish, English)49 p.En la localidad de Panguilemo (Talca, VII región de Chile), se llevó a cabo una serie vede tres ensayos para determinar la efectividad del extracto comercial de semillas de Neem (Azadirachta indica Juss.) NeemX, sobre el áfido Myzus persicae (Sulzer) sobre pimentón (Capsicum annum var. grossum) bajo condiciones de invernadero. Para ello, se evaluaron; distintas dosis del insecticida NeemX, una dosis del insecticida tradicional Aztec 140EW y un tratamiento control de sólo agua. Las dosis de NeemX fueron evaluadas en un rango de 1 a 20 cc/l, correspondientes a 4 y 80 ppm de azadirachtina respectivamente. Los resultados obtenidos demostraron que dosis de 1 cc/l fueron insuficientes para lograr un efecto insecticida. La LC50 fue de 1.067%, correspondiente a una dosis de 10.7 cc/l (aproximadamente 42.8 ppm de azadirachtina). La mayor reducción de la población de áfidos con respecto al control, fue obtenida con NeemX al 2%, correspondiente a una dosis de 20 cc/l (aproximadamente 80 ppm de azadirachtina), alcanzando niveles de mortalidad de 98.63%, sin presentar diferencias significativas con el tratamiento estándar (Aztec 140EW), el cual logró una mortalidad de 100%

Modified Dragonfly Optimisation for Distributed Energy Mix in Distribution Networks

This article presents a two-stage optimization model aiming to determine optimal energy mix in distribution networks, i.e., battery energy storage, fuel cell, and wind turbines. It aims to alleviate the impact of high renewable penetration on the systems. To solve the proposed complex optimization model, a standard variant of the dragonfly algorithm (DA) has been improved and then applied to find the optimal mix of distributed energy resources. The suggested improvements are validated before their application. A heuristic approach has also been introduced to solve the second stage problem that determines the optimal power dispatch of battery energy storage as per the size suggested by the first stage. The proposed framework was implemented on a benchmark 33-bus and a practical Indian 108-bus distribution network over different test cases. The proposed model for energy mix and modified DA technique has significantly enhanced the operational performance of the network in terms of average annual energy loss reduction, node voltage profiles, and demand fluctuation caused by renewables

A new potential nano-oncological therapy based on polyamino acid nanocapsules

A critical objective in cancer therapy is to reduce the systemic toxicity through the modification of the biodistribution of anticancer drugs. Herein, we disclose a new biodegradable nanocarrier, polyglutamic acid (PGA) nanocapsules, and present the in vivo pharmacokinetics/toxicity proof-of-concept for the anticancer drug plitidepsin. These novel nanocapsules were prepared using a modified solvent displacement technique where the polyamino acid was electrostatically deposited onto the lipid core. The nanocapsules exhibited an average size of 200 nm, a negative zeta potential and a great capacity for the encapsulation of plitidepsin (encapsulation efficiency above 90%). In addition, the nanocapsules could be freeze-dried and showed an adequate stability profile upon storage. Finally, the in vivo proof-of-concept studies performed in mice indicated that the encapsulation provided the drug with a prolonged blood circulation and a significantly reduced toxicity. In fact, the maximum tolerated dose of the nanoencapsulated drug was more than 3 times that of the reference formulation (Cremophor® EL plitidepsin solution). Overall, beyond the value of this specific formulation, the work reported here represents the evidence of the potential of polyamino acid nanocapsules in nano-oncological therapyThe authors would like to acknowledge financial support from CENIT-NANOFAR XS53 project, PharmaMar, Spain, the Ministry of Sciences and Innovation ((CTQ2009-10963), the Xunta de Galicia (Competitive Reference Groups-FEDER funds Ref. 2010/18, and CN2011/037) and the European Commission FP7 EraNet — EuroNanoMed Program-Instituto Carlos III (Lymphotarg proyect, Ref. PS09/02670). Giovanna Lollo has a fellowship from the Ministry of Education of Spain. Marcos Garcia Fuentes acknowledges an Isidro Parga Pondal Fellowship from Xunta de GaliciaS