Partial Discharge Simulations Used for the Design of a Non-Intrusive Cable Condition Monitoring Technique

The purpose of this paper is to investigate the effect of PD （partial discharge） activity within medium voltage XLPE （cross-linked polyethylene） cables. The effect of partial discharge was studied by means of a number of simulations. The simulations were based on the well-known three capacitor model for partial discharge. An equivalent circuit was derived for partial discharge due to a single void in the insulation material of a power cable. The results obtained from the simulations will form the basis of the design proses of a non-intrusive condition monitoring technique. The technique is based on the classification of discharge activity according to five levels of PD. Future work will include the improvement of the simulation model by investigating the high frequency model of a power cable as well as the statistical nature of PD activity. This will improve the accuracy of the simulation results when compared to actual measurements. The work discussed in this paper will be used to construct and calibrate a practical model which will make use of PD measurements for non-intrusive condition monitoring of medium voltage electrical cables.     

Solvent effect in the synthesis of nanostructured Pt–Sn/CNT as electrocatalysts for the electrooxidation of ethanol

Pt and Pt–Sn nanoparticles were synthesized and supported onto carbon nanotubes (CNT), the electrocatalytic activity towards the ethanol oxidation reaction was analyzed. The effect of the solvent employed for the synthesis was evaluated. Metal nanoparticles synthesis was made using water (Pt–Sn/CNT-W) or ethanol (Pt–Sn/CNT-E) as a solvent. Pt–Sn/CNT-W material presented only Pt–Sn alloy nanoparticles homogeneously distributed on the carbon nanotubes support. Pt–Sn/CNT-E sample showed non well-dispersed nanoparticles forming agglomerates along the CNTs surface with predominantly Sn⁴⁺ superficial species (SnO₂) as show the XPS, FTIR and electrochemical results. These surface arrangements had important effects on the electrocatalytic properties. Pt–Sn/CNT-W shows higher ethanol electrooxidation activity than the Pt–Sn/CNT-E, which is attributed to: a) the double catalytic effect and the intrinsic electronic mechanism favored by the presence of Sn; b) the good particle dispersion of the bimetallic active phase on the CNT and; c) the absence of SnO₂ species.     

Morphology and location manipulation of Fe nanoparticles on carbon nanofibers as catalysts for ammonia decomposition to generate hydrogen

Ammonia decomposition over Fe-based catalysts is a typical structure sensitive reaction, and the shape-controlled synthesis of Fe nanoparticles based on catalytic chemical vapor deposition (CCVD) method appears to be an effective method toward enhanced catalytic activity. The objective of this work is to understand effects of the reaction parameters on structural and textural properties of the resultant Fe catalysts and thus catalytic ammonia decomposition performance. The as-obtained catalysts are characterized by multiple techniques (N₂ physisorption, XRD, SEM, TEM, and Raman spectroscopy). Both the morphology and location of Fe nanoparticles are found to strongly depend on the partial pressure of H₂ as well as the growth time of CNFs. The long polyhedron shaped Fe nanoparticles on CNFs exhibit the highest activity among the prepared catalysts, which are relatively higher than the activities of the reported Fe based catalysts. The possible explanation for the good catalytic performance was proposed.     

Highly dispersed NiCu nanoparticles on SBA-15 for selective hydrogenation of methyl levulinate to γ-valerolactone

Copper and nickel nanoparticles highly dispersed on an ordered mesoporous silica support (SBA-15) were prepared by a glycol-assisted impregnation method and tested for the catalytic transfer hydrogenation reaction of methyl levulinate to γ-valerolactone (GVL). Characterizations by high resolution transmission electron microscopy, X-ray diffraction, N₂ sorption, H₂ temperature-programmed reduction and X-ray absorption spectroscopy confirm that the highly dispersed nanoparticles were well-anchored to the mesopores of SBA-15 with the strong interaction. Comparing to a catalyst synthesized by a conventional aqueous impregnation method, our catalyst shows a higher conversion and greater selectivity towards GVL of reaction at 140–170 °C using 2-propanol as a solvent and a hydrogen donor. Results showed that NiCu/SBA-15 (EG) had much better activity, providing 91.3% conversion of ML with 89.7% selectivity towards GVL in 3 h at 140 °C. The high compositional homogeneity, uniform distribution of the nanoparticles in the mesoporous channels and the strong interaction between the metal nanoparticles and SBA-15 contribute to the superior catalytic performance. This catalyst also demonstrates superb stability over the course of 5 reaction cycles without significant loss in catalytic activity and selectivity towards GVL formation.     

Clever Nuclear Fuel Technology

The purpose of given article-consideration of the basic features of modern manufacturing of nuclear fuel which would confirm fact, that the manufacturer does everything that its production would respond not only to requirements of the consumer, but also to its expected inquiries, and would correspond to intended purposes of fuel. It was defined main tendencies and features of modern technology, especially in nuclear fuel production, on base of meeting discussions, themes of journal articles on nuclear subject. They are correspond with practice of JSC NCCP （Novosibirsk Chemical Concentrates Plant） and listed in the paper. In result of it number of base features of any advanced technology, not only nuclear, described here with examples from NCCP＇s practice. Of course, there is no certain list of all attributes of modern manufacturing as there is no limit to its perfection. These categories are forming by current needs of the market, but listed ones must be.     

Dynamic Voltage Restorer with Active Disturbance Rejection Control

Power quality is one of the major concerns among consumers and electric utility companies. CUPS （custom power systems） devices are used to improve the quality of power and enhance the reliability of the power supply in the distribution networks. The DVR （dynamic voltage restorer） is an important CUPS device used to mitigate voltage sag/swell and imbalances. Various control techniques have been implemented to control the DVR, among which the PID （proportional-integral-derivative） controller is dominant because of its model independent property and its error driven technique. In this paper, a new controller based on the ADRC （active disturbance rejection control） concept is developed, and its performance is compared to that of the PID controller. The model of the DVR and its ADRC and PID controllers were developed under the MATLAB （matrix laboratory）/Simulink environment. The simulation results demonstrated the effectiveness of the ADRC over the PID controller.     

Utilization of Data Communication according to the IEC61850 Standard for Nuclear Power Plant Electrical Equipment Testing

This paper deals with an integration of directly measured electrical parameters with data acquired by data communication from protections and terminals into an advanced monitoring system. Based on the periodic test, the authors of this paper present the possibility of an extended evaluation and more accurate analysis of transient and failure events. For periodical testing, as implemented during the commissioning of power plants in the Czech Republic, a monitoring system of electrical equipment has been used, to record the courses of important electrical parameters and thus, proving the proper functioning of complex technological systems in various operation modes. Data from monitoring system were used to prove the successful results of the test or as a base data for further analysis of failures. The monitoring system has proved itself as a very useful device also when recording unexpected failure events, the cause of which was very quickly and accurately detected by the follow-up analysis. Initially, only the voltage and current data from measuring transformers, analogue transducers and contact relays were used as input data for the monitoring system. After the implementation of new digital protection technology and controlling terminals with inner data recorder, the data from digital devices could be also utilized for the monitoring system.     

Least Squares Fitting Based Fault Classification in Distribution Systems

Power systems are the largest and most complex human made systems, consisting of thousands of electrical sources, loads, transmission and distribution lines, power transformers, circuit breakers, etc. where faults always occurred. Faults can cause personnel and equipment safety problems, and can result in significant disruption to power supply and thus financial losses. In this paper we will present comprehensive mathematical suite to detect and classify fault dependent models of various types of power systems. This work will extract fault unique signatures by using polarization ellipse during the healthy condition and the polarization will be circular shape with radius equal the rated voltage of the system, but during the fault condition the polarization will be ellipse shape and the fault signature will be defined according the ellipse parameters major axis, minor axis, ellipticity and orientation angle, by using least squares criterion will define the ellipse parameters this system will identify and classify. This paper will be a milestone for extended paper based on the proposed mathematical modelling and applying it to identify, classify and localize with simulation model.     

Global Evaluation of Energy in Hybrid M-HTFC/MGT Systems in Cogenerative Arrangement

This work concerns the study of HSs （Hybrid Systems） that are made up of the integration of M-HTFC （Medium and High Temperature Fuel Cell） and MGT （Micro-Gas-Turbine）. Different typologies of hybrid systems are taken into account, which differ from each other in their plant layouts. The plants are considered in cogenerative arrangement. The aim of this study is to carry out an energetic analysis of the HS considered to obtain an analytical expression to depict the system operating in cogenerative arrangement. An energetic comparison among the systems analyzed based on some indexes is effected, which allows an evaluation of the plants performances in cogenerative arrangement. An energetic analysis is carried out, which is based on a ＂black box＂ depiction of the plant in which the components and the mutual interactions are highlighted. The fuel cell component of the plant is not analyzed as a black box, but each element that constitutes it, is elaborated as a subsystem.     

Analyzing the Share Composition of C02 Emissions in Asian Countries

This paper is concerned with the fossil fuel composition of carbon emissions in 10 selected Asian countries. It assesses how economic development may affect this composition through various channels. This paper contributes to the debate on the EKC （environmental Kuznets curve） puzzle, which hypothesizes an inverted U-shaped relationship between per capita income and pollution. The paper examines the EKC hypothesis in an empirical analysis of channels that may allow for this effect. In particular, a specific subset of this general paradigm is investigated using a fractional multinomial logit model to assess how indicators associated with economic development and energy prices affect carbon emissions from coal relative to those of natural gas and oil.     

3D Conceptual Modeling and Direct Utilization Calculations of the Albanian Low and Middle Enthalpy Geothermal Resources

The use of the Albanian geothermal springs and waters, for their curative effects （Natural SPA） dates back centuries, since the time of the Roman Empire, while their first modern use started only in 1937. Unfortunately they had not been used for its energetic values yet. The temperature of the water is above 60 ~C and the flow above 16 L/s, thus direct utilization is possible, in particular for space heating. Three-dimensional temperature field calculations and engineering calculations on a heating system with heat exchangers are presented here. The results show that the water temperature is expected to be stable and considerably higher temperature is expected through deep well drilling. The University＇s Campus of Tirana is composed of 29 buildings, which are partially heated through a coal heater. The installed capacity is 2,558 kW while the coal consumption is about 920 kg/h. The University＇s Campus of Tirana is one of the most important areas and with the highest density of population in Tirana, so it is the best area to show the heat exchanger efficiency. The economic analyses prove that the borehole heat exchangers are more convenient than the coal heating systems.     

Counter-Rotating Type Tidal Stream Power Unit Moored by Only One Cable

The authors have proposed that a counter-rotating type tidal stream power unit mounted rigidly on a pile, and outputs of the power unit and forces acting on the pile were investigated experimentally at a previous paper, A single propeller makes the pile undertake a reaction force orthogonal to the stream direction. On the contrary, proposed counter-rotating propellers do not require undertaking the reaction force of the pile, because the rotational torque is counter-balanced in the unit. This advantage means that the unit can be moored by only one cable. Continuously, this paper proposes such a power unit with tandem propellers, and experimentally investigates a behavior of the unit floating in a water channel. The vibrations of the power unit are induced from not only the individual but also the interacting rotations of the front and the rear propellers.     

Study of Properties of Lead Selenide （PbSe） Thin Films Deposited on TiO2

The study of nano properties of PbSe （lead selenide） thin films deposited on TiO2 semi conductor film prepared by sol gel method was a new work destined to perfect the nano materials used in photovoltaic energy. The growth of the first group of the fihns （Set 1： P（9）） ＆ P（14）） was based on the decomposition of lead citrate and sodium selenosulphite in the presence of sodium citrate and sodium hydroxide with ammonia and triethalamine （TEA） acting as the complexing agents and P.H stabilizers; while in the second group （Set 2： Pc15~）, the reaction bath was made up of solutions of lead nitrate Pb（NO3）2, PVA （polyvinyl alcohol）, H20 （distilled water）, NH3 （ammonia）, sodium selenosulphite （Na2SeSO3） and Triethalamine [N（CH2CH2OH）], which was used as the complexing agent. The deposited materials were identified by X-ray diffraction. In addition, nano optical and morphological investigations were also performed. The sample P9 has the lowest absorbance of about 0.3 nm in the ultra-violet region. It was found that there was a reduction in the optical absorbance as the wavelength increases. The optical band gap shows a range of 1.26-2.00 eV with sample PcIs~ having the lowest direct band gap.     

A comparison of experimental and numerical studies performed on a low-pressure turbine blade cascade at high-speed conditions, low reynolds numbers and various turbulence intensities

This paper focuses on a comparison of experimental and numerical investigations performed on a low-pressure mid-loaded turbine blade at operating conditions comprised of a wide range of Mach numbers(from 0.5-1.1),Reynolds numbers(from 0.4e+5-3.0e+5),flow incidence(-15-15 degrees) and three levels of free-stream turbulence intensities(2,5 and 10%).The experimental part of the work was performed in a high-speed linear cascade wind tunnel.The increased levels of turbulence were achieved by a passive grid placed at the cascade inlet.A two-dimensional flow field at the center of the blade was traversed pitch-wise upstream and downstream the cascade by means of a five-hole probe and a needle pressure probe,respectively.The blade loading was measured using the surface pressure taps evenly deployed at the blade mid-span along the suction and the pressure side.The inlet turbulence was investigated using the constant temperature anemometer technique with a dual sensor probe.Experimentally evaluated values of turbulent kinetic energy and its dissipation rate were then used as inputs for the numerical simulations.An in-house code based on a system of the Favre-averaged Navier-Stokes equation closed by a two-equation k-turbulence model was adopted for the predictions.The code utilizes an algebraic model of bypass transition valid both for attached as for separated flows taking in account the effect of free-stream turbulence and pressure gradient.The resulting comparison was carried out in terms of the kinetic energy loss coefficient,distributions of downstream wakes and blade velocity.Additionally a flow visualization was performed by means of the Schlieren technique in order to provide a further understanding of the studied phenomena.A few selected cases with a particular interest in the attached and separated flow transition are compared and discussed.     

Numerical Flow Simulation in Turbine Mode of Counter-Rotating Type Pumping Unit to Cooperate with Wind Turbine

This serial research has proposed the hybrid power system combined the wind power unit with the counter-rotating type pump-turbine unit, to provide the constant output for the grid system, even at the suddenly fluctuating/turbulent wind circumstance. In this paper, the tandem impellers prepared for the counter-rotating type pumping unit were operated at the turbine mode, and the performances and the flow conditions were investigated numerically with accompanying the experimental results. Even though providing the pumping unit for the turbine mode, the maximum hydraulic efficiency is close to one of the counter-rotating type hydroelectric unit designed exclusively for the turbine mode. Besides, the runners/impellers of the unit work evidently so as to coincide the angular momentum change through the front runners/impellers with that through the rear runners/impellers, namely to take the axial flow at not only the inlet but also the outlet, without the guide vanes. From these results, it can be concluded that this type unit is effective to work at not only the pumping but also the turbine modes.     

Magnetohydrodynamic Effect on Free Convection of Three Dimensional Laminar Flow in Porous Annulus

A numerical study has been carried out to investigate heat transfer by free convection under the effect of MHD （magnetohydrodynamic） for steady state three-dimensional laminar flow in horizontal and vertical cylindrical annulus filled with saturated porous media （sand silica） with fins attached to the inner cylinder. A single electric coil placed around the inner cylinder to generate a magnetic field. The governing equations which used are continuity, momentum （using Darcy＇s law） and energy equations which are transformed to dimensionless equations. The finite difference approach is used to obtain all the computational results using Fortran 90 program. The parameters affected on the system are Rayleigh number ranging within （102 ~ Ra＊ 〈 104）, and MHD （Mn） （0 〈_ Mn 〈_ 100） and radius ratio Rr （0.225, 0.338 and 0.435）. The results obtained are presented graphically in the form of streamline and isotherm contour plots and the results show that heat transfer decrease with the increase of magnetohydrodynamic. It was found that the average Nusselt number increase with Ra＊ and decrease with H~ Mn and Rr. A correlation for the average Nusselt number in terms of Ra＊ and Mn, has been developed for the inner cylinder.     

Integration of CATHENA Thermal-Hydraulic Model with CANDU 6 Analytical Simulator Controller

This paper introduces a powerful design and analysis tool named SIMCAT, that is developed to support applications to license a CANDU nuclear reactor, refurbish projects, and support the existing CANDU stations. It consists of the CATHENA （Canadian Algorithm for Thermo-Hydraulic Network Analysis）, the control logics from C6SIM （CANDU 6 Analytical Simulator）, and a communication protocol, PVM （parallel virtual machine）. This is the first time that CATHENA has been successfully coupled directly with a program written in another language. The independence of CATHENA and the C6SIM controllers allows the development of both CATHENA and C6SIM controller to proceed independently.     

Counter-Rotating Type Tidal Stream Power Unit Mounted on a Mono-pile

The authors have invented a unique counter-rotating type tidal stream power unit, which is composed of tandem propellers and a double rotational armature type generator without a stator. The front and the rear propellers drive, as for an upstream type, the inner and the outer rotational armatures in the counter-rotating directions respectively, which keep the rotational torques counter-balanced between both propellers and armatures. This paper investigates experimentally the output and forces acting on a pile in a water channel, to get design materials of the mono-pile type tidal stream power unit. The output is maximal at the moderate rotational speed, as the same as a wind turbine. The force acting on the pile is affected by the drag, the Karman vortex and the dynamic balances of the tandem propellers, and has dominant frequencies due to not only the individual but also the interacting rotation of the front and the rear propellers.     

Evaluation of Building Integrated Photovoltaic Systems＇ Potential in the Industrial Sector： Case Study of Oinofyta-Viotia Zone,Greece

The aim of this paper is to propose a flexible and accurate methodology for the evaluation of the BIPV （building integrated photovoltaic） potential on industrial building roofs. The use of more realistic and case specific data obtained by accurate technical on-site audits is proved to be of significant importance in the reliability of the proposed methodology results. Moreover, the most recent PV market information is used, considering however that this factor is rapidly changing during the last years, owed to the vast growth of the PV sector. To this end, emphasis is given on the country of Greece, where besides the fact that there is an increase of PV installations; no progress has been met in the use of BIPV systems in the industrial sector, opposite to the situation met in other EU countries. Acknowledging the above, the proposed methodology is currently applied so as to evaluate the BIPV potential of a large industrial zone close to the Greek capital, Athens. The results of this study can be used by both other researchers, for similar evaluations, and energy policy makers, to support the clean energy production concept on the basis of BIPV systems in industrial areas.