Electrical Power Fluctuations in a Network of DC/AC inverters in a Large PV Plant: relationship between correlation, distance and time scale

This paper analyzes the correlation between the fluctuations of the electrical power generated by the ensemble of 70 DC/AC inverters from a 45.6 MW PV plant. The use of real electrical power time series from a large collection of photovoltaic inverters of a same plant is an impor- tant contribution in the context of models built upon simplified assumptions to overcome the absence of such data. This data set is divided into three different fluctuation categories with a clustering proce- dure which performs correctly with the clearness index and the wavelet variances. Afterwards, the time dependent correlation between the electrical power time series of the inverters is esti- mated with the wavelet transform. The wavelet correlation depends on the distance between the inverters, the wavelet time scales and the daily fluctuation level. Correlation values for time scales below one minute are low without dependence on the daily fluctuation level. For time scales above 20 minutes, positive high correlation values are obtained, and the decay rate with the distance depends on the daily fluctuation level. At intermediate time scales the correlation depends strongly on the daily fluctuation level. The proposed methods have been implemented using free software. Source code is available as supplementary material.

Large-scale clustering measurements with photometric redshifts: comparing the dark matter haloes of X-ray AGN, star-forming and passive galaxies at z ≈ 1

We combine multi-wavelength data in the AEGIS-XD and C-COSMOS surveys to measure the typical dark matter halo mass of X-ray selected active galactic nuclei (AGN) [L_X(2–10 keV) > 10^42 erg s^− 1] in comparison with far-infrared selected star-forming galaxies detected in the Herschel/PEP survey (PACS Evolutionary Probe; L_IR > 10^11 L_⊙) and quiescent systems at z ≈ 1. We develop a novel method to measure the clustering of extragalactic populations that uses photometric redshift probability distribution functions in addition to any spectroscopy. This is advantageous in that all sources in the sample are used in the clustering analysis, not just the subset with secure spectroscopy. The method works best for large samples. The loss of accuracy because of the lack of spectroscopy is balanced by increasing the number of sources used to measure the clustering. We find that X-ray AGN, far-infrared selected star-forming galaxies and passive systems in the redshift interval 0.6 < z < 1.4 are found in haloes of similar mass, log M_DMH/(M_⊙ h^−1) ≈ 13.0. We argue that this is because the galaxies in all three samples (AGN, star-forming, passive) have similar stellar mass distributions, approximated by the J-band luminosity. Therefore, all galaxies that can potentially host X-ray AGN, because they have stellar masses in the appropriate range, live in dark matter haloes of log M_DMH/(M_⊙ h^−1) ≈ 13.0 independent of their star formation rates. This suggests that the stellar mass of X-ray AGN hosts is driving the observed clustering properties of this population. We also speculate that trends between AGN properties (e.g. luminosity, level of obscuration) and large-scale environment may be related to differences in the stellar mass of the host galaxies.

A classified catalogue of theological and religious books, comprising a large collection of standard works, American and foreign; old and rare works, and recent publications, to September 1, 1871. Also an addenda of miscellaneous literature, works of reference, &c. For sale by Smith, English & Co., booksellers and importers ...

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The pattern maker's assistant; embracing lathe work, branch work, ore work, sweep work, and practical gear construction; the preparation and use of tools; together with a large collection of useful and valuable tables.

Mode of access: Internet.

English and French furniture of the eighteenth century; comprising a large collection of those designs most esteemed by connoisseurs, including both simple and elaborate styles, with descriptive text accompanying each piece ...

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Fudge in Ireland : a collection of letters, poems, and legends, concerning the castle, the courts, the college, the corporation, and the country at large.

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Parish psalmody. A collection of psalms and hymns for public worship: containing Dr. Watts's versification of the psalms of David, entire, a large portion of Dr. Watts's hymns, and psalms and hymns by other authors, selected and original.

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Parish psalmody. A collection of psalms and hymns for public worship: containing Dr. Watts's versification of the psalms of David, entire, a large portion of Dr. Watts's hymns, and psalms and hymns by other authors, selected and original.

Words only.

Miscellanea mathematica: consisting of a large collection of curious mathematical problems, and their solutions. Together with many other important disquisitions in various branches of the mathematics. Being the literary correspondence of several eminent mathematicians.

Includes tables and diagrams.

The statutes at large; : being a collection of all the laws of Virginia, from the first session of the legislature, in the year 1619. : Published pursuant to an act of the General Assembly of Virginia, passed on the fifth day of February one thousand eight hundred and eight. : Volume I[-XIII]. /

Each volume contains a certification statement and an errata statement, either tipped in or printed on the title page verso.