bluuebunny/crossref_metadata_2025 huggingface dataset:
STUDI PERBANDINGAN BIOSURFAKTAN Pseudomonas aeruginosa IA7d DAN SURFAKTAN SINTETIK Tween-80 DALAM BIODEGRADASI SOLAR OLEH MIKROBA PERAIRAN PELABUHAN TANJUNG PERAK SURABAYA
Authors: Ni’matuzahroh Ni’matuzahroh , Yachya Arif , Tanjung Mulyadi
Published: April 2017

This research aimed to know the influence of addition crude product Pseudomonas aeruginosa IA7d biosurfactant from substrate hexadecane and diesel fuel in supporting activity of diesel fuel biodegradation and both potention to replace synthetic surfactant for hydrocarbon remediation. Biodegradation test was done by experimental in laboratory scale by Tween-80 as synthetic surfactant comparator. Growth culture was from seawater of Tanjung Perak Harbor Surabaya include various microbe types in its. 2 percent (w/v) of diesel fuel and three surfactants test (0.70 percent w/v crude product P. aeruginosa IA7d biosurfactant from hexadecane substrate; 60,69 percent w/v crude product P. aeruginosa IA7d biosurfactant from diesel fuel substrate; and 0.10 percent w/v synthetic surfactant Tween 80) at uniform surface tension of surfactant solution (54.03 mN/m) were added into 30 ml seawater sample. Cultures were incubated at room temperature (30 °C) during 14 days with shaking (90 rpm). Result of biodegradation test showed the third addition of surfactants test had an effect on acceleration of diesel fuel biodegradation activity that proved at the increased of microbial count (bacterium, yeast, and mould) and decreased of diesel fuel concentration was shown by chromatograms area of diesel fuel. Highest degradation was successively reached by culture got crude product P. aeruginosa IA7d biosurfactant from diesel fuel substrate (88.034 percent), crude product P. aeruginosa IA7d biosurfactant from hexadecane substrate (80.908 percent), synthetic surfactant Tween-80 (54.732 percent), and control that was without addition surfactant test (0.132 percent). Base on number of microbial count, percentage of decreasing chromatogram peaks of diesel fuel from each surfactant test, and price substrate produce (diesel fuel and hexadecane) among both crude product P. aeruginosa IA7d biosurfactant, known that the crude product P. aeruginosa IA7d biosurfactant from diesel fuel substrate had highest ability acceleration to biodegradation activity on diesel fuel and had a potency to replace synthetic surfactant for remediation hydrocarbon application in environment.
PENGKAJIAN KAPANG ENDOFIT DARI TAMAN NASIONAL GUNUNG HALIMUN SEBAGAI PENGHASIL GLUKOAMILASE
Authors: Melliawati Ruth , Suherman Ricky Setiadi , Subardjo Bambang
Published: April 2017

Production of glucoamylase generally used through the fermentation-using microorganism. One of microorganism source which never been studied are from endophyte fungus. The purpose of this research is to study the potential microbes of Gunung Halimun Nasional Park (GHNP) for glucoamylase production. Thirty-seven isolate of endophyte fungi has been investigated for the ability of glucoamylase production on PSA (Potato starch agar) media with the strength of clear zone and colony. The potential isolates inoculated to Czapek media to produce glucoamylase on 50 ml scale and measured its activity every 24 hours of incubation time for 96 hours. The best isolate then was reproduced on the larger media (100 ml), and resumed with filtration and ultra-filtration. The enzyme activity, specific activity, and degree of protein was measured in every phase. Selection of amylolitic strength resulted that HL.110F.488 produced the highest amylolitic strength with halo size of 10.47 cm2, or equal with hydrolysis of starch of 0.0494 gram for 96 hours, while both isolate HL.44F.199 and HL.45F.205 had low amylolitic capacities but a very wide of colony growth, each 38.54 cm2 and 30.76 cm2. Isolat HL.44F.199 produced the highest enzyme activity of 5452.633 unit at 72 hours fermentation, while isolate HL.45F.205 with 4725.58 units at 72 hours fermentation and isolate HL.110F.488 with 3167.609 units at 96 hours fermentation. Glucoamylase has been reproduced by isolate HL.44F.199 on volume media 100 ml. The results show that enzyme activity is 4197.10 units with specific activity 2851.44 U/mg proteins, both get an increasing result after filtration and ultra-filtration reach out 5910.86 units and 4534.45 U/mg proteins.
BIODEGRADASI MINYAK OLEH Rhodotorula dan Candida HASIL ISOLASI DARI PELABUHAN TANJUNG PERAK SURABAYA
Authors: Nurhariyati Tri , Ni’matuzahroh Ni’matuzahroh , Surtiningsih Tini
Published: April 2017

A research about isolation and capability of isolat yeast from Tanjung Perak Harbor, Surabaya in degrading kerosen, gas oil, and lubricant were conducted. This research were done to know the influence of Rhodotorula, Candida and Mix of Rhodotorula and Candida, the influence of oil type and interaction of both (between yeast and oil) in decreasing oil weight. Research design was laboratory experimental and using the factorial 4x3 with five replication. The data were analyzed by two-way ANOVA (p mean 0.05) and followed by t test. The result of the biodegradation test showed that the kind of yeast, the kind of oil weight and interaction of both influence in decreasing of oil weight. The most decreasing of oil weight obtained by mix of Rhodotorula and Candida (82.55 percent), kerosen (66.59 percent) and combination mix of yeast (Rhodotorula and Candida) and kerosen (89.32 percent).
SELEKSI KHAMIR YANG BERBASIS SELENIUM SEBAGAI SUMBER BAHAN BIOAKTIF DAN UJI MODULASI APOPTOSIS SELULER SACCHAROMYCES CEREVISIAE
Authors: Yulinery Titin , Handayani W. R. , Nurhidayat Novik
Published: April 2017

The selection of yeast from volcanic soil as bioactive source based on selenium and apoptosis modulation of Saccharomyces cerevisiae have been done. Isolation of yeast used the dilution method. Furthermore, the isolates were selected for resistance and accumulation test of selenium, catalyze test, resistance to high temperature and test of toxicity to garlic. The Inhibition activity was detected by using paper disc method. The result showed that 11 isolates from Kerinci and 4 isolates from Rinjani had been determined. 10 isolates were resistant to SeO2 toxicity, could accumulate Se, and had the activity of catalyze. Isolates 15 and 394.1 were sensitive to garlic toxicity, could inhibit 3.71 cm and 4.16 cm, respectively. All the isolates collected were mesophylic, and could grow at the temperature 28–30 °C. The highest Se concentration of the isolates was 0.92 ppm and 0.78 ppm, which produced by isolate 53 and 15 respectively. Isolate 15 were lower than isolate 53 in apoptosis modulation yeast LIPIMC strain and yeast BJ 3505 strain (10.54 percent and 14.24 percent, respectively). The highest frequent of petite was BJ 3505 strain.
POTENSI PENGGUNAAN BEBERAPA VARIETAS SORGUM MANIS (Sorghum bicolor (L.) Moench) SEBAGAI TANAMAN PAKAN
Authors: Purnomohadi Mustikoweni
Published: April 2017

Sweet sorghum is a versatile crop that can be used as grain crop, sugar alcohol production and even as forage crop. The aim of this study was to evaluate the potential use of sweet sorghum either as grain crop or forage crop. The experiment used four varieties of sweet sorghum: Rio, Cawley, Keller and Wray, which were planted in polybag with six replication using Completely Randomized Design. The result of the research showed that Keller and Wray had longer vegetative growth, and good quality of chemical composition for forage than Rio and Cawley.
POPULASI JAMUR MIKORIZA VESIKULAR-ARBUSKULAR PADA LAHAN BEKAS GALIAN EMAS YANG DIREKLAMASI DENGAN LEGUM TUMBUH CEPAT DIKOMBINASIKAN DENGAN PENUTUP TANAH DAN MIKROBA
Authors: Suciatmih Suciatmih
Published: April 2017

A field work has been carried out to study the population of vesicular-arbuscular mycorrhizal (VAM) fungi on degraded gold mining land that was reclamated with fast growing legume (Enterolobium sp. and Acacia mangium) trees in combination with cover crops (Centrosema pubescen dan Flemingia congesta) and microbe (VAM fungi, Rhizobium sp. and mixed Rhizobium sp. and phosphate solubilizing bacteria) inoculation. Reclamation with fast growing legumes in combination with cover crops and microbe inoculation on the degraded land increased the population of VAM fungi. After 1.5 years, the population of the fungi on the reclamated land increased from 3.4 (control) to 6.1–80.5 spore/g soil. The highest spore population resulted by combination between Acacia mangium, C. pubescen, and VAM fungi (V2I1C1) plot followed by combination between Acacia mangium without cover crop, and VAM fungi inoculation (V2I1C0) plot and combination between Enterolobium sp. without cover crop and mixed Rhizobium and phosphate solubilizing bacteria inoculation (V1I3Co) plot were 80.5, 56.0 and 51.8 respectively.
STUDI MORFOMETRI IKAN WADER GOA (Puntius microps Gunther, 1868) YANG UNIK DAN DILINDUNGI UNDANG-UNDANG
Authors: Haryono Haryono
Published: April 2017

Wader goa (Puntius microps) is an endemic fish species and has unique habitat especially at cave in Java, also was protected by Indonesian Government therefore interesting to study. This fish related to Wader Cakul (Puntius binotatus) that wide distributed. The aims of study are to know the distinctive characters of both species by morphomethric and meristic methods. The results show that both species was different by morphometric and can not separated by meristic. The main characters are HW, SNL, ED, CPL and MXBL that joined of three functions showed 100% separated. Among P. binotatus, population from Java more related to Sumatra than Kalimantan.
The Impact of Small HPP’s in the Energy Balance of Albanian Power System
Authors: M.Çelo  , E.Zeqo  , A.Ibrahimi  , R.Bualoti
Published: May 2017

The global trend of electrical energy price, in the conditions of a normal economic development, increases progressively. Albania is a developing country and the consume of electrical energy per individual is growing up during the two last decades. The hydropower installed capacity of Albania is only 35% of hydropower potential. The increase of generating capacity in the Albanian Power System and therefore the increase of the electricity production is one of the most high priorities of the policy sector. This has made possible, through construction of new generation facilities and optimal use of existing generation capacities, to ensure harmonization of all aspects related to indicators of operation security of the system, the quality of service of the good electrical energy and its cost. This paper presents the development performance of generation capacities focused to the economic aspects as well as to the impact of Small Hydro Power Plants (SHPPs) in the country's energy production balance.
Energy storage systems for frequency stability enhancement in small-isolated power systems
Authors: I. Egido  , L. Sigrist  , E. Lobato  , L. Rouco
Published: April 2017

. Frequency stability is one of the most relevant issues in operation of small isolated power systems. High penetration of renewals may significantly affect frequency stability of isolated power systems since renewable energy sources connected to the grid through power electronic interfaces do not provide either inertia or primary frequency regulation. This paper describes a research and demonstration project led by Endesa aimed at testing the state of the art of energy storage systems in isolated power system. Power systems of the Spanish Canary Islands will be used as test bench. The paper shows the contribution of La Palma ultra-capacitor and La Gomera flywheel to frequency stability and control enhancement.
Observability of a 2-branch Double-Layer-Capacitor
Authors: F. Alonge  , M. Cirrincione  , G. Vitale  , G. Rodonò
Published: April 2017

The paper proposes a study of the observability of a 2-branch Double-Layer Capacitor (DLC) mathematical model, derived from its well known 2-branch nonlinear physical model. The study is a basis to perform the diagnosis of the system by employing observers. The analysis is carried out by means of the sufficient rank condition of the observability matrix for nonlinear models. It is shown that the rank condition is satisfied everywhere in the two-dimensional state space, except for a characteristic curve in the plane defined by the two state variables. This curve is usually outside the usual range of operation of Double-Layer Capacitors available on the market. Finally, it is shown that the above curve is sensitive to the resistance of the branch containing the nonlinear capacitance, i.e. the faster branch. In particular, increasing this resistance can cause the curve to intersect the region of usual range of operation of a DLC.
Benefits that could be achieved by a proper reactive power generation in small photovoltaic systems operating inside low voltage distribution network
Authors: Katarina Dežan  , Ernest Belič  , Gorazd Štumberger
Published: April 2017

The reduction of feed-in tariffs and subsidies in the last years substantially decreased the interest of investors for photovoltaic (PV) systems in individual countries and in the European Union in general. From the viewpoint of electricity distribution system operators (DSO) and electricity distribution companies, the PV systems are often observed as the systems that cause additional costs and make network operation difficult, but must be connected to the electricity network due to the existing legislation. Thus, the power of PV systems newly connected to the electricity networks per year decreases substantially. The fact that PV systems can be used not only for active, but also for reactive power generation, is often neglected. If reactive power in PV systems is generated properly, it can satisfy the local reactive power demand, which leads to reduction of network losses. This paper focuses on an existing low voltage distribution network with installed 100 kWp PV power. Its goal is to perform a sensitivity analysis of benefits in the network that could be achieved by the reduction of network energy losses and by the locally generated reactive power, both achieved by PV systems capable to generate reactive power.
Development of a mobile photovoltaic stand-alone energy supply system
Authors: K.K.T. Thanapalan  , T.J. Stockley  , M.A. Bowkett  , J.G. Williams
Published: April 2017

This paper discusses a systematic approach for the design and implementation of a mobile stand-alone photovoltaic (PV) system. The system is designed on the plug and play principle. There are a number of potential system configurations for stand-alone PV system including mobile stand-alone PV system. In remote locations, mobile stand-alone configurations are of interest, and may prove more cost effective than a grid connected systems. In this paper a mobile stand-alone PV system model is developed within the MatLAB/Simulink platform for system analysis and performance optimization. The potential yield of such a mobile stand-alone PV system design is investigated using data collected at an industrial test site and the performance of the PV system under variable conditions determined. This paper also described an optimal design and implementation of an efficient mobile stand-alone PV system. The structure of the PV system and design methodologies is also discussed. Tests were conducted with the implementation of the new design and the results show that the system performance improved significantly.
Optimization of total investment cost of solar distribution network
Authors: M.Siali  , S. Fergani  , S.Flazi  , A. Boudghene Stambouli
Published: April 2017

. The position of the PV generator and the electrical cables sections influence the whole cost of installation during the operation life of a network. The aim of our work is to find the number of the solar generators, and the optimal location for installing them in order to optimize the total investment cost of a distribution network. In this paper, we will discuss the methods that we have developed to optimize this cost, and study the influence of cables cross sections, the number and the locations of the generators on the optimization. We have proposed three methods: -The gravity center method to optimize the volume of copper taking into account only the voltage drop sections. -The method of the minimum copper volume center, to optimize the same cost but taking into account all the technical sections and the economic sections. -The method of the minimum cost center to optimize the overall investment cost using the optimal sections. After that, we have studied the influence of the number of the generators on the optimization using the method of minimum cost center. The use of MATLAB software has helped us to verify and confirm our results.
Analysis of probabilistic properties of harmonic currents of loads connected to the high voltage networks
Authors: I. Kovernikova
Published: April 2017

The paper presents the results of a statistical analysis of the probabilistic properties of harmonic currents of the loads connected to the high voltage networks. The analysis was based on the measurements of current of three facilities: an aluminum smelter shop, a paper mill and a railway traction substation. These loads have a large capacity and receive electric power from the 220 kV network. The main technological equipment of the facilities is a source of harmonics. The facilities have different load curves. The load of the aluminum smelter shop during a day time remains almost constant. The load of the paper mill varies during a day time due to the shift operation. The load of the traction substation is abruptly variable. The analysis shows that the arrays of measured harmonic currents are non-stationary and contain anomalous elements. In the currents of each load there are prevalent harmonic components. It is established that in the process of measurement the direction of harmonic current flows changed. The harmonic currents sometimes flow from the network to the load and sometimes vice versa. The probability density functions for the values of harmonic currents in most of the cases are a composition of several known distributions.
A study on the voltage calculation method for ESS operation plan in Hybrid Generation System
Authors: S. Jung  , G. Jang
Published: April 2017

The designed hybrid generation system (HGS) not only consider the voltage condition of connection point but also do limit output profile by following the transmission system operator’s directions. Therefore, when developing large-scaled system including a number of HGS, appropriate compensation strategy based on the system components and impacts should be formulized with considering inner system’s characteristics. The ESS operation plan in HGS should be supported by precise voltage expectation method because the system has large physical areas: it includes almost 150m DC section. Especially, since the previous system is not considering power limiting method at the DC section which is integrated with wave generators, an appropriate ESS compensation could provide a lots of solutions such as power control and quality issue. In this paper, an active power control algorithm with expected voltage based on the DC power flow is introduced, and imposed to the simulation process that is performed on EMTDC environment. Further, the comparison with the normal control process is carried out based on the composed layout in ongoing project.
Thermal Performance of a Single Slope Solar Water Still with Enhanced Solar Heating System
Authors: Abdullah M. Al Shabibi  , M. Tahat
Published: April 2017

This paper investigates experimentally the thermal performance of conventional solar water still with enhanced solar heating system. A number of variables have been considered including the water depth inside the still and the inlet saline water temperature to the solar still from the preheater solar collector system and the still basin geometry. The still is modified to include preheating solar system, to preheat saline water before entering the solar still, in order to enhance its hourly or daily yield of pure water. A single slope conventional solar still with solar preheating unit was constructed and experimentally tested under different weather conditions. Different quantities of water in the solar still basin were tested to find the effect of water quantity on the hourly yield and still’s thermal efficiency. It was found that 1 cm depth and finned still basin gives the best performance in terms of fresh water yield and thermal efficiency. The addition of the solar water preheater to the system has significantly increases the inlet basin saline water temperature to almost saturated temperature and saline water in the basin needed only small heat to be vaporized and hence increases the production of fresh water and enhances the solar still thermal efficiency.
Displacement Ventilation System Combined with a Novel Evaporative Cooled Ceiling for a Typical Office in the City of Beirut: Performance Evaluation
Authors: M. Itani  , K. Ghali  , N. Ghaddar
Published: April 2017

Displacement ventilation (DV) system incorporated with  a  novel  evaporative  cooled  ceiling,  Maisotsenko  cycle  (M-cycle) is a passive technique used to enhance the load removal in spaces.  This  study  examines  the  performance  of  the  integrated system in increasing the load removal of the DV system beyond the  40  W/m2  limit  with  no  additional  energy  consumption  for  a typical  office  in  Beirut.  Mathematical  models  for  the  space  and the   evaporative   cooled   ceiling   will   be   developed   and   then validated  through  experimentation.  Simulations  are  performed under  different  supply  air  relative  humidity  values,  were  an improvement  in  sensible  load  removal  of  18.65%,  44.3%  and 72.25%  at  supply  air  relative  humidity  of  90%,  50%  and  10% respectively. Results showed better cooling performance at lower supply air relative humidity.
Impact of Wind Geographical Correlation in Reliability Assessment Studies Using Sequential Monte Carlo Simulations
Authors: F. Vallée  , J-F. Toubeau  , Z. De Grève  , J. Lobry
Published: April 2017

Electrical generation based on the use of renewable energies is emerging in modern grids. In that way, one of the most popular solutions as well in transmission as in distribution grids is certainly coming from wind energy. However, wind resources on a given location randomly fluctuate with time and have thus a major impact on the capacity of the electrical system to continuously face the load. In order to evaluate this impact and to consequently adapt required reinforcements, Monte Carlo simulations are often used. Those approach can be either sequential or not. Nowadays, load shifting solutions (storage, demand side management…) are practically set in order to adapt consumption to time varying generation without involving too consequent investments. In that way, sequential approach is currently preferred when it comes to long-term planning evaluation and adapted time series models are developed to characterize wind generation on a given site. The consideration of the geographical correlation between those models has been recently investigated in some references. This paper proposes to complete those contributions by evaluating the impact of wind geographical correlation on classical reliability indices such as the Loss of Load Expectation (LOLE) or the Expected Energy not Served (EENS).
Verification and Implementation of Pseudo-Random-Binary-Sequences for Online Determination of Grid Impedance Spectrum
Authors: Udit Tewari  , Surena Neshvad  , Daniel Goldbach  , Jürgen Sachau
Published: April 2017

Renewable   energy   technologies   as   Distributed Energy Sources (DER) connected via power inverter on medium or  low  voltage  grid  are  expected  to  become a  more  important part of future generation system.  Therefore, it has to be ensured that  their  integration  doesn’t  jeopardize  the  stability  and performance  of  the  power  system  which  can  only  be  attained with  improved  monitoring  and  control  of  system  parameters  on real time basis such as the equivalent  grid impedance seen from the grid-tied DER. In order to ensure this, this paper investigates a   reliable   and   precise   method   for   online   equivalent   grid impedance    estimation    based    on    Pseudo-Random-Binary-Sequences  (PRBS),  which  has  been  extensively  used  in  system identification,  communication  and  information  theory.  It  allows real  time  computation  of  complete  spectrum  of  grid  impedance at  the  Point  of  Common  Coupling  (PCC)  by  injecting  broad spectrum    identification    patterns    of    harmonics    and    inter-harmonics.  The  impedance  spectrum  thus,  can  be used  for  filter design,  power  quality  evaluations,  grid  status determination  and inverter tuning. In this paper, a PRBS-based active identification method   is   tested   and   implemented   on   an   off-grid   system consisting  of  a  3  phase  inverter  prototype  developed  in  the  lab and has been used to identify the grid impedance spectrum of a 3 phase  purely  inductive  load  connected  at  the  output  of  the inverter. The results obtained confirm that the  method estimates the  grid  impedance  spectrum  over  a  significant  frequency  range with high resolution on real time basis.
Economic Optimization of a Hybrid Solar-Wind Power Plant in Chile
Authors: José O. Maldifassi  , Julián Lizama M  , Ignacio Mongillo M
Published: April 2017

This study analyzes the optimal configuration of a hybrid solar-wind power plant in terms of levelized electricity generating costs for a period of 20 years. In spite that the site for the plant has one of the most intense solar radiation levels in the world, the final result is that only wind generators should be used to provide electricity to the nearby Chuquicamata mining complex in northern Chile.
Reduction of energy losses achieved by an optimal reactive power generation in photovoltaic systems installed inside a low voltage distribution network
Authors: Ernest Belič  , Katarina Dežan  , Niko Lukač  , Gorazd Štumberger
Published: April 2017

This paper deals with the evaluation of electrical energy savings in a low voltage distribution network, gathered by reduced energy losses. The latter is achieved by optimal reactive power generation of photovoltaic (PV) systems, where losses in the low voltage network and distribution transformer are taken into consideration. The energy savings are determined for three typical low voltage networks: urban, rural and rural with long distance LV lines. In the discussed networks PV systems are installed. The study of network electrical energy savings is performed for smaller PV systems with 5 kWp per unit and for larger units, all for the same total PV power installed in the network. The results shows, that significant electrical energy savings can be achieved in networks, where PV systems are installed away from the transformer station or smaller PV systems are installed at sites, where consumption is present.
The influence of diesel generators on frequency stability for isolated grids with high wind power penetration
Authors: Georgia Papaioannou  , Ignacio Talavera  , Jutta Hanson
Published: April 2017

The power generation of isolated power systems is based on expensive oil-fired or diesel conventional power plants. The combination of wind/diesel hybrid power systems is one of the most common proposed and promising solution for stability problems. This paper deals with the definition of an optimal combination for diesel generators from a technical point of view. On the one hand the extreme case that the power infeed equals the power demand without power reserves is considered and on the other hand a high amount of wind power is taken into consideration. The main goal is to find out if in case of dynamic events which are related to frequency stability, the power system would collapse for the operating conditions of minimum load and high wind power penetration. The scope is both to ensure system stability for different combinations of conventional generation, as well as to verify grid code requirements for providing active power support from Renewable Energy Sources that is required for the power system of the island of Lesbos in Greece.
Probabilistic Study of the Impact on the Network Equipment of Changing Load Profiles in Modern Low Voltage Grids
Authors: J-F. Toubeau  , V. Klonari  , Z. De Grève  , J. Lobry  , F. Vallée
Published: April 2017

The paper proposes a measurement-based method for the long-term analysis of the low-voltage (LV) distribution network. This work focuses on line power flows susceptible to cause a premature deterioration of cables and on power exchanged at the MV/LV transformer that can potentially induce adverse repercussions on its lifetime. Such estimations are indeed essential as the distribution systems are more and more frequently subject to stress conditions due to the increase of photovoltaic (PV) installations and significant loads such as electric vehicles. In this context, using a probabilistic approach is more beneficial than worst-case scenarios that yield much more restrictive conclusions. The approach is implemented in a pseudo-sequential Monte-Carlo environment and is based on quarter-hourly energy flows recorded by smart meters installed at some LV customers of the Belgian distribution network. These devices are currently located in some scarce selected areas but the penetration rate is expected to massively grow in the future. With the increase of collected measurements, this analysis tool will therefore allow Distribution System Operators (DSOs) to accurately assess important parameters for a secure and efficient operation of the network.
Influence of a metallic wall on 245 kV disconnector behaviour during short-circuit test
Authors: J. A. Güemes  , A. M. Iraolagoitia  , P. Fernández
Published: April 2017

When testing electrical devices, it is not always possible to provide locals with dimensions large enough to guarantee that metallic elements (walls or other elements) not essential for the test, are located far enough to ensure that they will not affect the distribution of the electric or magnetic field, or forces that may appear during testing of the devices. Some questions to be answered are: a) test results are distorted by presence of these metallic elements? b) if so, to what degree are influenced? and c) how could we quantify its value without building new laboratories, and raising economic cost? The main objective of this paper is to analyse influence of a metallic wall on behaviour of a 245 kV disconnector during short-circuit test developed in laboratory and, compare electrodynamic force on disconnector when the test is carried out with and without metallic wall. Behaviour simulation of disconnector is carried out using finite element method (FEM). Force is calculated using Lorenz force method. Results show that calculated force is strongly dependent on model size and element size.
Accumulation small hydro power plant on lake - Slovenian case
Authors: L. Somi  , K. Deželak  , G. Štumberger
Published: April 2017

Depends on amount of water per person, Slovenia is among the richest countries in Europe with almost four times the European average. The production of energy from water to wire is basically possible on the whole country area. This work deals with the area near to Ledava river, where the water accumulation system was built around 1970. From economical point of view, the aforementioned system is not really exploited. There are different possibilities, how to exploit the whole system, as with fishing industry, soaking industry or with convertion of hydro energy into electrical energy as part of renewable production units. The last mentioned is the part of presented research work in proposed paper.
Electricity generation from tidal power in artificial “albúfera” in the Rio Negro Province, Argentina
Authors: Luis Bertani  , Carlos Labriola  , Aiel Marchegiani  , Orlando Audisio  , Mr. Samuel Troncoso Schenker
Published: April 2017

In this paper we consider the possibility of using the absolute depression “bajo del Gualicho” (- 72 m), Río Negro Province, Argentina, to generate electricity by means of a connection with the sea in the Gulf of San Matias, located about 25 km to the East [1]. This would allow the formation of a large lake that would create an "artificial albúfera" which will cover an area of about 1234 km2 . This lake will be exposed to tidal by means of a combination of a channel and four tunels located between the sea and the lake. Taking the reference of Puerto San Antonio Este, the average tidal range reaches 6.73m [2], so that each high tide (lasting 6 hours. 20 minutes) would the water flow to the lake and the sea at low tide it would travel in the opposite direction. This project is made by means of a multidisciplinary research group with advice of Hydraulic Laboratory of University of La Plata and Renewable Energy Group of Academic Unit of Caleta Olivia [3], National University of Austral patagonia, Province of Santa Cruz. Also this project has the endorsement of Government of Rio Negro Province.
Behaviour of Mechanically Switched Capacitors with Damping Network (MSCDN) during Energization
Authors: S. Weck  , I. Talavera  , J. Hanson
Published: April 2017

Reactive  Power  Compensation  is  becoming  in-creasingly  important,  as  more  and  more  conventional  generation  is  replaced by dispersed energy sources, which do not contribute to  voltage  stability  in  the  transmission  grid.  The  Mechanically  Switched Capacitors with Damping Network (MSCDN) is a cost-efficient  solution,  combining  reactive  power  compensation  and  harmonic mitigation. In this paper, the MSCDN is analysed with respect to its design parameters to determine the electrical stress on  the  components  during  energization.  The  analysis  is  done  in  Laplace  and  frequency  domain,  as  well  as  through  time-domain numeric simulation.
Hybrid Reluctance Machines with U-Shaped Electromagnets and Permanent Magnets
Authors: P.Andrada  , B. Blanque  , E. Martinez  , M.Torrent  , O. Rolando Ávila  , M. Gomila  , X. Adelantado
Published: April 2017

This paper is about hybrid reluctance machines, in which the stator or fixed part has a combination of U-shaped electromagnets with permanents magnets placed between their arms while the moving part is simply a structure with salient poles. They can be designed to build different types of rotary or linear electric motors and generators with outstanding performances. In this paper, first, the principle of operation of these machines is explained. Then different types of hybrid reluctance machines using this particular structural configuration are described showing their potential based on simulations and experimental results.
Sensitivity analysis of the Electrical Stresses in Mechanically Switched Capacitors with Damping Network due to Components’ Tolerances
Authors: I. Talavera  , S. Weck  , J. Hanson
Published: April 2017

In this paper, the influence of the tolerances of the components on the steady-state electrical stresses of Mechanically Switched Capacitors with Damping Network (MSCDN) is assessed. For this purpose, a sensitivity analysis for 380-kVconnected MSCDNs with different quality factors and tuning frequencies is carried out. For the calculations, the level of harmonics defined in IEC 61000-3-6 has been considered. The calculations are based on simulations using ideal models of the MSCDN’s components.
Analysis of an Advanced Compounding Strategy based on Reactive Power Flow Measurement in the Medium Voltage Network
Authors: P. Franz  , G. Stapff  , I. Talavera  , J. Hanson
Published: April 2017

As well known, the increased share of renewable energies has led to new challenges for the electrical power system in Germany. Since the majority of renewable generation units are installed in the lower voltage levels, problems of congestion and voltage deviation occur more often. Commonly, the Distribution System Operators in Germany take advantage of a reactive power support by decentralised energy resources to ensure static voltage stability. The drawback of the support of reactive power for static voltage stability is the increasing demand for inductive reactive power by the distribution network which has to be compensated by the connected high voltage network. Besides, the power losses rise as well because of the additional reactive power flows. Therefore, other methods for voltage regulation like the use of compounding strategies at transformer stations could be advantageous to prevent the violation of voltage limits. This paper compares four different strategies of controlling the on-load tap-changer of the HV/MV-transformers in distribution networks and the effects on voltage deviation and power losses. A special focus is given to an advanced compounding strategy which adapts the control profiles of the compounding strategy dependent on the reactive power flow at the transformer as a second input parameter.
Robust Control Applied to a Photovoltaic Array Emulator Using Buck Converter
Authors: L. P. Sampaio  , S. A. O. Silva
Published: April 2017

Considering the increasing use of photovoltaic energy in the actual scenario of electrical power generation, this paper presents the design of an electronic emulator which is able to emulate the characteristics of a PV array. The proposed photovoltaic array emulator is implemented using a mathematical model that represents the equivalent electrical circuit of a photovoltaic cell. The reference signal is obtained from the mathematical model obtained for controlling the dc-dc buck converter, which is used to reproduce the characteristic PV curve (current-voltage). The controller is designed by means of linear matrix inequalities (D-stability criteria in conjunction with H∞ constraints), considering uncertain parameters in the converter model. Finally, from computer simulations, the proposed work can emulate the PV behavior considering atmospheric variations, such as solar radiation and temperature, in order to evaluate the performance of the system and to validate the proposal of the work.
Analysis of the electrical energy intensity under energy efficiency actions
Authors: López Pereiro D  , Zaragoza S  , Tarrío J  , Naya S  , Álvarez A.
Published: April 2017

This paper shows the real benefits of energy efficiency if they are regulated by energy indicators on electricity end-use in a industrial warehouse under the Spanish tariff regime.
Analysis of LED lighting for a service ship
Authors: JM. Orbaneja  , A. Álvarez  , J. López-Beceiro  , R. Artiaga  , B. Álvarez
Published: April 2017

The main objective of the study is to assess the cost to replace the traditional illumination by LED and analyze the impact on reduction CO2 emissions and the fuel consumption.
Techno-Economic Design of a Stand-Alone Renewable Energy System
Authors: S. Abdelkader
Published: April 2017

This paper presents a method for the design of a stand-alone renewable energy system supplying an isolated load. In this work, the stand-alone system consists of wind generator, battery storage and backed up by a diesel generator. However, all other forms of renewable energy, storage and backup systems can be included. The proposed method aims at securing the energy needs of the load most economically and reliably through determining the optimum component sizes. A linear programming model is developed to determine the optimum sizes of system components based on an average day data. Day to day variations are then represented as a stochastic Markov process where an average cycle of the system is constructed and utilized for modifying component sizes to assure the desired level of reliability.
In performance analysis of transmission lines facing lightning, it is extremely important the study of voltages induced by indirect discharges because they occur frequently. The voltages induced by such discharges, can reach high amplitudes, that requ
Authors: P.C.A. Mota  , J.R. Camacho  , M.L.R. Chaves
Published: April 2017

In performance analysis of transmission lines facing lightning, it is extremely important the study of voltages induced by indirect discharges because they occur frequently. The voltages induced by such discharges, can reach high amplitudes, that requires more attention to this phenomenon. The induced voltages can cause shutdowns of the network and even damage the equipment connected to it. As an alternative to analysis of the induced voltage by indirect discharges, this paper proposes the computational modeling of the phenomenon, based on the methodology developed by Sune Rusck, which is highly regarded and used for this type of study. The environment used will be EMTP/ATPDraw, which is public domain, besides being widely used as reference in studies of electromagnetic transients in power systems. From computer simulations, induced voltages are obtained, and presented the analyzes of the influence of some parameters in its amplitude and waveform.
Identification of potential users of photovoltaic conversion
Authors: D. L. do Carmo  , R. C. Souza  , M. N. Frota
Published: April 2017

The growing demand for electricity resulted from the continuous technical progress and its disturbing impacts on the environment motivate the search for technological alternatives for sustainable energy generation. The power consumption changes from consumer to consumer and depends on the nature of the activity it performs. In general, activities of trade and industry consume more energy during business hours while residential buildings do at dusk and at night. With the exception of Saturdays, Sundays and holidays, period of greatest consumption of electricity in Rio de Janeiro is between 17h30 and 20h30. In summer months, the intensive use of air conditioning anticipates peak hours for 14h00. When technically possible, the use of photovoltaic conversion in these peak times, therefore, constitutes a smart strategy for load shifting the peak hours to off-peak for large consumers with contract demand in medium and high voltage. This alternative has two impacts: it relieves the systems at peak times and allows the utility to defer investments in their installed infrastructure. This paper, while discussing the technical conditions and the benefits of using photovoltaic systems in Brazil, proposes a method to identify, based on local solarimetric conditions, the photovoltaic conversion potential users.
New models related with heating and cooling of an old building in Évora (South of Portugal)
Authors: M.R. Duque
Published: April 2017

The work presented here is part of a more extensive study related to a system of heating and cooling an old building of the 16th century, of the Evora University using water retired from four boreholes located in the vicinity of the building. The principal aim of this work is to introduce solar radiation data including its variations during a day, in winter and in summer and use them as a limit to the direct solar radiation received by the building, Our models include heat transfer by conduction, convection and radiation. A special attention is dedicated to temperature and humidity values needed to work. The results obtained are used to program the time interval and the conditions of operation of the system mounted in the building.
Power Supply Issues in E-health Monitoring Applications
Authors: Alan Davidson  , Neha Mathur  , Ivan Glesk  , Arjan Buis
Published: April 2017

Abstract. Recent years have seen a rapid growth in the development of e-health systems for the continuous remote patient monitoring of physiological data such as temperature, heart rate (HR), Blood pressure (BP), oxygenation (SpO2), respiration and glucose levels. The roll-out of such schemes show promise in delivering improvements in patient care while at the same time reducing both the demand for resources and the financial burden on healthcare systems. These wearable monitoring systems are used to monitor, log and transmit patient data to a central health authority. Depending on the patient, it is often critical that the monitoring system reliability is high to deliver the appropriate patient care and ensure patient safety. However, since wearable systems are solely dependent on battery power, continuous monitoring will rapidly deplete the battery energy making the system prone to failure. In this paper, methods to reduce power consumption will be discussed using the example of prosthetic socket temperature monitoring data
A First Approach on the Fault Impedance Impact on Voltage Sags Studies
Authors: A. C. L. Ramos  , A. J. Batista  , R. C. Leborgne  , E. G. Domingues  , W. P. Calixto  , A. J. Alves
Published: April 2017

An analysis of the fault impedance impact on studies of voltage sags caused by system faults is presented. The simulation of 62 case studies of phase-to-ground faults on 13.8, 69, 138 and 230 kV transmission lines were performed and the voltage of a 380 V sensitive industrial busbar consumer was monitored. These lines are part of the electrical system of the city of Goiania, Brazil. For each case study, different fault positions were simulated by considering resistive fault impedances of 0, 2, 5, 10, 15 Ω or a random fault impedance with a specific distribution function. Long-term simulation scenarios were obtained by the Monte Carlo method and analyzed based on their cumulative distribution functions and probability density curves of voltage sags. This is one major contribution of this work. We found that, the greater the fault impedance, the smaller the average number of voltage sags expected per year at the end-user busbar. However, the behavior of the average number of voltage sags of a given class of magnitude with the fault impedance does not follow a general law.
Fault detection in a three-phase system grid connected using SOGI structure to calculate vector components
Authors: ROCHA, C. X  , CAMACHO, J. R.  , VIAJANTE, G. P
Published: April 2017

Fault detection algorithms are very important in grid connected systems. They are used to analyze a three-phase system behavior in real time. When something wrong happens, they start some procedures to avoid the collapse. A three-phase system cannot be considered a simply sum of three independent phases, which leads us to apply some vector transform to obtain a more elegant representation of systems. A control system grid connected is based on the vector transform. In this paper we analyze a fault detection performance between some vector transform algorithms, and present a good way to accomplish these transforms using a SOGI (Second Order Generalized Integrator).
Calculation of involved energies in thermal plasma at the opening of high voltage breakers
Authors: A. Ziani  , H. Moulai  , A. Nacer
Published: April 2017

Usually, calculations of involved energies in thermal plasma at the opening of high voltage breakers are led by using dimensional type models (1D, 2D and 3D) founded on assumptions sufficiently precise. This survey deals with the determination of temperature and thermal transfers of arc plasma quenching in a high voltage breaker by coupling a 0D (time dependent) arc model with the heat equation. This approach enabled to refine the thermal balance and to evidence the particular importance of the thermal radiation. Also, investigations are focused on the influence of the deionisation constant of the extinguisher gas on the plasma conductance and temperature variations which are checking parameters of the extinction. The obtained results are in good agreement with measurements performed by other authors.
Assessment of Power Level Variations in a Small PV System
Authors: P. Janik  , Z. Waclawek  , J. Rezmer
Published: April 2017

There is a significant content of high variations of power levels in a PV system. This variations are considered as an deterioration of power quality and therefore should be quantified, further minimised. The ripple content in the power curve was assessed with wavelets. A bell shaped function was correlated to a power curve using optimisation techniques. It resulted in a very compact characterisation of the power curve and enabled conceptual correlation between real power curve and power output line required by the utility.