Improving the accuracy of multisided travelling wave determination of location of a fault in a power line by means of the difference–distance-measuring technique

The double-ended travelling wave method of determination of location of a fault in electrical networks has significant errors due to changes in the propagation velocity of electromagnetic waves. We have developed a travelling wave method of improving the accuracy of location of a fault determination in power transmission lines that is based on navigation algorithms. The method is applicable to lines with branches. The distance to fault determination for the developed method is up to twice as accurate as the double-ended travelling wave location of a fault method. The accuracy of the developed method is less influenced by external factors (change of sag, soil resistance, the instantaneous value of the current at the fault time) than is the accuracy of the double-ended travelling wave location of a fault method. The proposed method allows reducing the errors in determining distance to the location of a fault, and its accuracy is less affected by external factors. The developed method can be incorporated into existing and prospective devices based on travelling wave methods of location of a fault determination.     

Set up of a Screen-Printing Procedure for the Production of a β Alumina-Based Gas Sensor*

A gas sensor based on a -alumina thick film was recently developed on a laboratory scale. This sensor can be successfully used for selective detection of CO and NO_x, resulting from an appropriate choice of the working temperature of the sensing element. This paper deals with the approach of the industrial transfer of the sensor prototype, mainly concerning the scale-up of the screen-printing procedure from a hand-operated apparatus to an industrial production machine. Many parameters were already investigated during the laboratory development, namely the ink composition in terms of organic/inorganic component ratio, the type and amount of the liquid dispersant and rheological agent, the composition and softening temperature of the binder, the -alumina/binder weight ratio. During the industrial transfer, some other parameters must be considered, such as the particle size distribution of the ceramic components of the ink, the influence of the mesh number of the screen fabric on the surface texture of the -alumina film, the viscosity performances of the ink as a function of the applied shear rate and ageing. A common commercial metallic paste was also used as reference for optimizing the characteristics of the -alumina based ink.     

Is the Security of Electricity Supply a Public Good?

So far in the debates over electricity market reform, there has been little attempt to evaluate just how significant the security of supply is to electricity consumers and to think of it in terms of public good criteria.     

Multiple-Input–Multiple-Output Linear-Quadratic Control of the Energy Production of a Synchronous Generator in a Nuclear Power Plant

—A multiple-input–multiple-output linear-quadratic servo controller is proposed for a synchronous generator operating in a nuclear power plant that keeps the active power at the desired level and performs reactive power reference tracking using the reactive power demand from a central dispatch center. The controller design was based on the locally linearized version of a previous non-linear dynamical model of the synchronous electrical generator [1 Anderson, P., and Fouad, A., Power-Systems-Control and Stability, Ames, IA: The IOWA State University Press, Chap. 4, 1977. [Google Scholar], 2 Fodor, A., Magyar, A., and Hangos, K.M., Control-oriented modeling of the energy-production of a synchronous generator in a nuclear power plant, Energy, . 39, pp. 135–145, 2012.[Crossref], [Web of Science ®] , [Google Scholar]], the parameters of which have been identified using measured data from Paks Nuclear Power Plant (Hungary). The method can easily be applied to any industrial power plant generator connected to the electrical grid after estimating its parameters. The proposed observer-based multiple-input–multiple-output state feedback controller is a linear-quadratic servo controller with very good reference tracking and disturbance rejection properties, which were confirmed by simulation experiments.     

Water chemistry of the system for cooling the electrical generator’ stator of the power unit at a thermal power station

Results from studies of the water chemistry used in the system for cooling the stator windings of alternators used in supercritical-pressure power units are presented, and a solution is suggested using which the standardized pH value of cooling water is maintained in the range 8.0–9.0. It is shown that addition of NaOH in the water cooling system when a drop of pH value occurs cannot fully satisfy the requirements of the operating circular due to low buffer properties of aqueous medium.     

Influence of the sizes and initial temperature of the drum of a combined-cycle plant’s heat recovery boiler on its stressed state during the startup

Results from a study for analyzing the effect the geometrical characteristics of a heat-recovery boiler’s high-pressure drum and its initial temperature have on the drum’s stressed state during the startup are presented. Recommendations for determining the starting mode are given.     

Choosing a Pathway Towards Advancing China's Reform of the Power Industry

●A reasonable and transparent pricing mechanism; ●A "top-down" project approval mechanism; ●An effective demand forecasting system; ●An incentive mechanism for private and foreign investments; and ● A fundamental of efficiency improvement Considering China's reality when moving towards marketization In April 2007, the State Council issued the "Proposal for the Implementation of Furthering the Institutional Reform of the Power Industry during the 11th Five-Year Plan." The proposal clearly states the main tasks of the power reform for the next steps.     

Spectroscopic sampling of the left side of long-TE spin echoes: a free lunch?

Objective

Use of spectroscopically-acquired spin echoes typically involves Fourier transformation of the right side of the echo while largely neglecting the left side. For sufficiently long echo times, the left side may have enough spectral resolution to offer some utility. Since the acquisition of this side is “free”, we deemed it worthy of attention and investigated the spectral properties and information content of this data.

Materials and methods

Theoretical expressions for left- and right-side spectra were derived assuming Lorentzian frequency distributions. For left-side spectra, three regimes were identified based upon the relative magnitudes of reversible and irreversible transverse relaxation rates, R ₂′ and R ₂, respectively. Point-resolved spectroscopy (PRESS) data from muscle, fat deposit and bone marrow were acquired at 1.5 T to test aspects of the theoretical expressions.

Results

For muscle water or methylene marrow resonances, left-side signals were substantially or moderately larger than right-side signals but were similar in magnitude for muscle choline and creatine resonances. Left- versus right-side spectral-peak amplitude ratios depend sensitively on the relative values of R ₂ and R ₂′, which can be estimated given this ratio and a right-side linewidth measurement.

Conclusion

Left-side spectra can be used to augment signal-to-noise and to estimate spectral R ₂ and R ₂′ values under some circumstances.

     

Deuterium NMR study of the MP-2269: albumin interaction — a step forward to the dynamics of non-covalent binding

MP-2269, the Gd(III) complex of 4-pcntylbicyclo[2.2.2] octane-l-carboxyl-di-L-aspartyl-lysinc-derived-DTPA, is a small Gd-agent that binds non-covalently to scrum albumin in vivo to assume the enhanced relaxivities associated with macromolecular agents, (due in part to increased rotational correlation time, τ_R). To further explore the fundamental parameters that govern the dynamics of water proton relaxation enhancement by this prototypical albumin-binding agent, the rotational correlation time (τ_R) for the deuterated La(III) analog of MP-2269 has been independently measured in the presence and absence of 4% albumin using²H-NMR approaches. The diamagnetic La(III) analog of MP-2269 was deuterated at the α-position of the carbonyl groups.²H-NMR studies were conducted at 7.05T (46 MHz) and 310°K on a Bruker NMR spectrometer. Spectral deconvolution permitted calculation of transverse relaxation rates, 1/T₂, from the NMR linewidths and subsequently, τ_R. The results yielded a τ_R of the albumin bound complex of ∼ 8 ns. This value is intermediate between those earlier estimated by¹⁷O-NMR (∼ 1 ns) and¹H-NMRD (∼ 20–50 ns) and significantly shorter than that of albumin. The²H-NMR study results also indicate that the exchange between free and albumin-bound forms of the La(III) analog is slow (exchange lifetimes > 1 ms). This slow exchange does not affect the water residence lifetimes (τ_M 140-280 ns).     

Some features of the effect the pH value and the physicochemical properties of boric acid have on mass transfer in a VVER reactor’s core

Certain features of the effect of boric acid in the reactor coolant of nuclear power installations equipped with a VVER-440 reactor on mass transfer in the reactor core are considered. It is determined that formation of boric acid polyborate complexes begins under field conditions at a temperature of 300°C when the boric acid concentration is equal to around 0.065 mol/L (4 g/L). Operations for decontaminating the reactor coolant system entail a growth of corrosion product concentration in the coolant, which gives rise to formation of iron borates in the zones where subcooled boiling of coolant takes place and to the effect of axial offset anomalies. A model for simulating variation of pressure drop in a VVER-440 reactor’s core that has invariable parameters during the entire fuel campaign is developed by additionally taking into account the concentrations of boric acid polyborate complexes and the quantity of corrosion products (Fe, Ni) represented by the ratio of their solubilities.     

Choosing a Pathway Towards Advancing China＇s Reform of the Power Industry

Considering China＇s reality when moving towards marketization
In April 2007, the State Council issued the ＂Proposal for the Implementation of Furthering the Institutional Reform of the Power Industry during the 11th Five-Year Plan.＂ The proposal clearly states the main tasks of the power reform for the next steps.     

Specific features of the stressed state arising in the high-pressure drum of a combined-cycle plant’s heat-recovery boiler during its startup

Results obtained from a study of the stressed state arising in the wall of a heat-recovery boiler’s high-pressure drum during its startup are presented, and the effect of the pressure growth rate on the maximal stresses arising in the wall is analyzed. Recommendations for determining the optimal loading rate of the heat-recovery boiler are given.     

Transmission Pricing: Are We Finally on the Brink of a Breakthrough?

Although the Federal Energy Regulatory Commission has been understandably wary of embracing market-based solutions, its approval of a high-voltage, direct current cable underneath Long Island Sound is a fundamental, if discrete, step in a new and promising direction for transmission pricing.     

Novel economic modelling of a peer-to-peer electricity market with the inclusion of distributed energy storage—The possible case of a more robust and better electricity grid

Current electricity distribution systems allow prosumers to sell their surplus electricity back to the Distributed Network Operator (DNO). The export tariffs at which these sell-backs take place are considerably lower than the feed-in tariffs, offering little incentive to prosumers to sell their surplus energy. A peer-to-peer (P2P) electricity market where consumers and prosumers can interact by selling and buying energy between them at a premium rate that is lower than the standard feed-in tariffs but higher than the export tariffs is proposed. Such a system was modelled to process transactions every 20 s, and a simulation tool was created to obtain the total daily money flows between a consumer-prosumer pair. The inclusion of a Distributed Storage System (DSS) is also considered in the modelled system and simulation. The simulation results showed that the inclusion of a DSS is always beneficial for all parties in economic terms: consumers could save up to 6.4 % on the cost of their electricity while prosumers could save up to 49.1 %. A DSS could generate an income flow for the DNO of up to 6.9p/day per each consumer-prosumer pair.     

Electromagnetic field calculation inside a conducting cylinder of finite length using the T-Ω method

Contents The solution of a 3-dimensional problem is, almost in all cases, a quite difficult task, since a great computational effort is required. AT- method accompanied by a boundary element technique is presented for the evaluation of the field inside a conducting cylinder of finite length. The excitation is a current dipole with harmonic time variation (electric Hertzian dipole), located somewhere inside the cylinder. According to the method the problem is split into smaller independent successive problems, requiring much less computational effort.

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Berechnung des elektromagnetischen Feldes innerhalb eines leitenden Zylinders endlicher Länge mit Hilfe der T--Methode

Übersicht Die Lösung des dreidimensionalen Problems ist, fast in allen Fällen, wegen der großen Mühe, die bei den Computerberechnungen erforderlich ist, sehr schwierig. EineT--Methode kombiniert mit einer Randelementtechnik für die Berechnung des Feldes innerhalb eines leitenden Zylinders endlicher Länge wird präsentiert. Ein Hertzscher Dipol an einer beliebigen Stelle innerhalb des Zylinders stellt die Felderregung dar. Entsprechend der Methode wird das Problem in mehrere kleinere, unabhängige sukzessive Probleme, die viel weniger Mühe bei der Computerberechnung erfordern, unterteilt.

     

The key player or just a paper tiger? The effectiveness of ACER in the creation and functioning of the EU’s internal energy market

Our research, which aims to present the effectiveness of the European Union’s internal energy market, shows the results of a recent survey conducted among representatives of national energy regulators and exchanges from eleven EU Member States. Due to the choice of the research method based on the SOFIA concept, the results constitute a new original contribution to the existing treasury of knowledge in the field of the European energy market. In the concrete case of sociological analysis, we checked how successful the Agency for the Cooperation of Energy Regulators (ACER) is in establishing and ensuring the functioning of the internal energy market in the EU. The survey examines the performance of ACER, which became operational in March 2011 and is intended to contribute to the establishment and functioning of the EU’s internal energy market from the perspective of ACER, national energy regulators and energy exchanges in EU Member States. ACER’s basic mission is to ensure the successful functioning of the energy market, which, as a result (of successful operation), will lead to the full integration of the internal market, and consumers will receive energy uninterruptedly from all parts of the Union. Our research also showed that ACER is crucial for the functioning of the internal market. Most representatives of national regulators and energy exchanges agree that the EU already has a functioning internal energy market and that ACER is crucial for the functioning of the internal energy market.     

A method of using neural fuzzy models to determine the technical state of a diesel locomotive’s electrical equipment

Equipment for carrying out onboard diagnostics is an important component in systems for controlling the state and reliability of rolling stock, in particular, that of diesel locomotives. It makes it possible to monitor a locomotive’s service quality, to detect and predict changes in its technical state without interrupting the carriage process, and to efficiently use the high-cost stationary and local diagnostic means, as well as to correct service time and volume by taking into account the real technical state. Therefore, it is important to develop methods for determining the technical state of locomotive units by using an MCS-T(N,E) (micro-processor control system) locomotive’s diagnostic subsystem of a locomotive and software for processing the measurement data. The main aim of such a method is to monitor the technical state of a locomotive’s equipment and predict changes in it. At the present time, simplified diagnostic models are used to solve such problems. However, to increase the efficiency and reliability of the process of checking complicated objects such as a locomotive, it is necessary to use more complex diagnostic models based on artificial neural networks. A way to use a neural-network method and neural fuzzy diagnostic models for diagnosing the excitation system of traction generators of modern diesel locomotives is presented in this paper. Information collected by the MCS-TP subsystem is used as diagnostic information. It is transferred online to a remote diagnostic server. The method for diagnosing the excitation system of a traction generator is checked by processing the measurement information.     

Development of hydropower resources on the upper and middle reaches of the Yellow River

China covers a vast territory with many rivers and richhydropower potential.China's exploitable hydropowercapacity amounts to 378 GW which corresponds to an annual powergeneration of 1920 TWh.This makes China the leading country inthe world as far as hydropower resources are concerned.At the end of 1990,the country's hydro capacity developedwas 36.0 GW,accounting for 26.1% of the country's total,with anannual electricity production of 126.4 TWh,accounting for almost20.34% of the country's total.By the end of this century,China's hydropower capacity willreach 75-80 GW,constituting 19.8-21.1% of the country's