scholarly journals Selecting Ultracapacitors for Smoothing Voltage Deviations in Local Grids Fed by Transformer with Tap-Changer and Distributed PV Facilities

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 357 ◽  
Author(s):  
Oz Sorkin ◽  
Eliyahu Farber ◽  
Moshe Averbukh
Keyword(s):  
Time Constant ◽  
Power Plants ◽  
Numerical Procedure ◽  
Voltage Regulation ◽  
Solar Irradiation ◽  
Approximation Procedure ◽  
Non Linear ◽  
Low Pass ◽  
Linear Circuits ◽  
Selection Of

Widespread use of photovoltaic (PV) small and middle-power plants close or inside existing townships and villages may cause significant deviations of the grid voltage. Owing to the oscillation of solar irradiation and corresponding power flows these voltage instabilities can damage equipment and must be prevented. Designated for the voltage regulation tap-changers in distribution transformers located in a significant distance of such settlements have a sluggish response time. As a possible answer for their delay is the smoothing energy of flows in PV power installation by intermittent capacitor low-pass filtering (LPF) located near those PV facilities. The application of ultracapacitors (UC) for LPF is remarkable due to their sustainability and relatively low costs of energy storage. The parameters selection of such appliances is a well-designed procedure for linear circuits. However, DC–AC inverters in PV facilities are represented by a power (instead of a voltage) source. As a result, the total circuit including such LPF becomes a non-linear and its transient process and consequently, its efficiency is difficult to assess requiring each time of development the UC storage an application complex numerical procedure. Engineers are usual to work with linear circuits that are describing fine by a time constant is designated as a multiplication of a capacitance times load equivalent resistance. In the case of PV DC–AC inverters, such an approach can be applied as well but a value of a time constant should be corrected. Considering a significant cost of UC storage, the non-optimal selection of a correcting coefficient may cause considerable loses. Submitted in the presented article is an original approximation procedure giving an efficiently approachable technique to select correcting coefficient for describing non-linear dynamic process by its linear analog. This way the development low-pass UC filtering in electrical systems with PV plants becomes more efficient and simpler task.

scholarly journals New Strategies and Simulation Tools to Optically Design a Field of Heliostats

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Paola Sansoni ◽  
Franco Francini ◽  
Daniela Fontani ◽  
Elisa Sani ◽  
Luca Mercatelli ◽  
...  
Keyword(s):  
Power Plants ◽  
Solar Power ◽  
Optical Design ◽  
Field Analysis ◽  
Solar Irradiation ◽  
Research Experience ◽  
Simulation Tools ◽  
Solar Power Plants ◽  
New Strategies ◽  
Selection Of

A heliostats field is an array of mirrors concentrating the solar power on a receiver, typically placed on a tower. Our research experience in the optical design of heliostats fields for Concentrating Solar Power plants suggested using apposite simulation procedures, which were especially developed to simplify the reproduction of heliostats fields and to support in the analysis of the tower plant performances. Our most practically useful simulation tools are presented in this paper with exemplificative application results. The proposed strategies are addressed to solve specific problems and to evidence particularly crucial features. The main program facilitates the heliostats field analysis, exploiting the integration between our software code andZemax. A side program permits to assess effects of seasonal and daily variations of solar irradiation. Another dedicated side code simplifies the selection of aCompound Parabolic Concentratoras secondary optics.

scholarly journals Relationship between Age and Value of Information for a Noisy Ornstein–Uhlenbeck Process

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 940
Author(s):  
Zijing Wang ◽  
Mihai-Alin Badiu ◽  
Justin P. Coon
Keyword(s):  
Value Of Information ◽  
Markov Models ◽  
Upper Bounds ◽  
Distribution Functions ◽  
Lower And Upper Bounds ◽  
Uhlenbeck Process ◽  
Source Data ◽  
Non Linear ◽  
Queue Model ◽  
Selection Of

The age of information (AoI) has been widely used to quantify the information freshness in real-time status update systems. As the AoI is independent of the inherent property of the source data and the context, we introduce a mutual information-based value of information (VoI) framework for hidden Markov models. In this paper, we investigate the VoI and its relationship to the AoI for a noisy Ornstein–Uhlenbeck (OU) process. We explore the effects of correlation and noise on their relationship, and find logarithmic, exponential and linear dependencies between the two in three different regimes. This gives the formal justification for the selection of non-linear AoI functions previously reported in other works. Moreover, we study the statistical properties of the VoI in the example of a queue model, deriving its distribution functions and moments. The lower and upper bounds of the average VoI are also analysed, which can be used for the design and optimisation of freshness-aware networks. Numerical results are presented and further show that, compared with the traditional linear age and some basic non-linear age functions, the proposed VoI framework is more general and suitable for various contexts.

A Novel Non-Linear Programming-Based Coal Blending Technology for Power Plants

2000 ◽  
Vol 78 (1) ◽  
pp. 118-124 ◽  
Author(s):  
Chungen Yin ◽  
Zhongyang Luo ◽  
Junhu Zhou ◽  
Kefa Cen
Keyword(s):  
Linear Programming ◽  
Power Plants ◽  
Non Linear Programming ◽  
Coal Blending ◽  
Non Linear

Measurement of Cr(VI) Based on Absorption Spectrum through Plastic Fiber

2014 ◽  
Vol 687-691 ◽  
pp. 948-951
Author(s):  
Wei Jun Hu
Keyword(s):  
Signal Processing ◽  
Absorption Spectrum ◽  
Optic Fiber ◽  
Signal Process ◽  
Linear Fitting ◽  
Non Linear ◽  
Low Pass ◽  
Measurement Experiment

Considering the advantage of optic fiber, a methods of measuring Cr (VI) based on absorption spectrum through plastic fiber is introduced, which includes structure of measurement, experiment process, spectrum signal process. After signal processing based on low-pass filtering and non-linear fitting, five concentrations of Cr (VI) can be differed easily and the peak values of spectrum corresponding to five concentrations accord with the Longbow Bill's law . In this way, the measurement concentration can limit down to 0. 0.0660 μg/ml.

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