Real Time Fault Location Using the Retardation Method

A new method for short circuit fault location is proposed based on instantaneous signal measurement and its derivatives, and is based on the retardation phenomena. The difference between the times in which a signal is registered in two detectors is used to locate the fault. Although a description of faults in terms of a lumped circuit is useful for elucidating the methods for detecting the fault. This description will not suffice to describe the fault signal propagation hence a distributed models is needed which is given in terms of the telegraph equations. Those equations are used to derive a transmission line transfer function, and an exact analytical description of the short circuit signal propagating in the transmission line is obtained. The analytical solution was verified both by numerical simulations and experimentally.

Spectral binning of precomputed correlated-k coefficients

With the major increase in the volume of the spectroscopic line lists needed to perform accurate radiative transfer calculations, disseminating accurate radiative data has become almost as much a challenge as computing it. Considering that many planetary science applications are only looking for heating rates or mid-to-low resolution spectra, any approach enabling such computations in an accurate and flexible way at a fraction of the computing and storage costs is highly valuable. For many of these reasons, the correlated-k approach has become very popular. Its major weakness has been the lack of ways to adapt the spectral grid/resolution of precomputed k-coefficients, making it difficult to distribute a generic database suited for many different applications. Currently, most users still need to have access to a line-by-line transfer code with the relevant line lists or high-resolution cross sections to compute k-coefficient tables at the desired resolution. In this work, we demonstrate that precomputed k-coefficients can be binned to a lower spectral resolution without any additional assumptions, and show how this can be done in practice. We then show that this binning procedure does not introduce any significant loss in accuracy. Along the way, we quantify how such an approach compares very favorably with the sampled cross section approach. This opens up a new avenue to deliver accurate radiative transfer data by providing mid-resolution k-coefficient tables to users who can later tailor those tables to their needs on the fly. To help with this final step, we briefly present Exo_k, an open-access, open-source Python library designed to handle, tailor, and use many different formats of k-coefficient and cross-section tables in an easy and computationally efficient way.

Sistem Proteksi Pelepasan Beban dengan Metode Descending Menggunakan Macro VBA

The last few months, PT. PLN WKSKT deliberately goes out to prevent the failure of the generator system network. Blackouts occur because there are uneven load uses. The use of the largest load is in the Barikin transmission line scheme towards the Tanjung and Cempaka direction. Both schemes are crucial load conditions when there is a disruption in the transmission line. This can interfere with the transmission of the load on targets that are in the two schemes, cause trips and blackouts. To resolve the issue, PT. PLN WKSKT create a special scheme for the protection system loads on specific targets. Which system can sort the target load from large to small. Descending is a sorting method that can complete the purpose of a protection system. With this method the target load is sorted and then calculated in VBA macros. The target load that has been sorted is then added to the equivalent of the line transfer. Calculations performed on VBA macros aim to obtain load release status based on enable, ready and trip indications. All three indicators used to monitor the load condition real time. So that the protection system is able to avoid interference that can cause black out on the electrical system.

Photoionization models for extreme Lyα λ1216 and Hell λ1640 line ratios in quasar halos, and PopIII vs. AGN diagnostics

Aims. We explore potential mechanisms to produce extremely high Lyα/HeII flux ratios, or to enhance the observed number of Lyα photons per incident ionizing photon, in extended active galactic nucleus (AGN) photoionized nebulae at high-redshift. Methods. We computed models to simulate, in the low density regime, photoionization of interstellar gas by the radiation field of a luminous AGN. We have explored the impact of ionization parameter, gas metallicity, ionizing spectrum, electron energy distribution, and cloud viewing angle on the relative fluxes of Lyα, HeII and other lines, and on the observed number of Lyα photons per incident ionizing photon. We have compared our model results with recent observations of quasar Lyα halos at z ∼ 3.5. Results. Low ionization parameter, a relatively soft or filtered ionizing spectrum, low gas metallicity, κ-distributed electron energies, or reflection of Lyα photons by neutral hydrogen can all result in significantly enhanced Lyα relative to other lines (≥10%), with log Lyα/HeII reaching values of up to 4.6. In the cases of low gas metallicity, reflection by HI, or a hard or filtered ionizing spectrum, the observed number of Lyα photons per incident ionizing photon is itself significantly enhanced above the nominal Case B value of 0.66 due to collisional excitation, reaching values as high as 5.3 in an “extreme case” model which combines several of these effects. We find that at low gas metallicity (e.g. Z/Z⊙ = 0.1) the production of Lyα photons is predominantly via collisional excitation rather than by recombination. In addition, we find that the collisional excitation of Lyα becomes much more efficient if the ionizing continuum spectrum has been pre-filtered through an optically thin screen of gas closer to the AGN (e.g. by a wide-angle, feedback-driven outflow). We also show that the Lyα and HeII emission line ratios of a sample of previously studied quasars at z ∼ 3.5 are consistent with AGN-photoionization of gas with moderate to low metallicity and/or low ionization parameter, without requiring exotic ionization or excitation mechanisms such as strong line-transfer effects. In addition, we present a set of UV-optical diagnostic diagrams to distinguish between photoionization by Pop III stars and photoionization by an AGN.

Unscented Particle Smoother and Its Application to Transfer Alignment of Airborne Distributed POS

This paper deals with the problem of state estimation for the transfer alignment of airborne distributed position and orientation system (distributed POS). For a nonlinear system, especially with large initial attitude errors, the performance of linear estimation methods will degrade. In this paper, a nonlinear smoothing algorithm called the unscented particle smoother (UPS) is proposed and utilized in the off-line transfer alignment of airborne distributed POS. In this algorithm, the measurements are first processed by the forward unscented particle filter (UPF) and then a backward smoother is used to achieve the improved solution. The performance of this algorithm is compared with that of a similar smoother known as the unscented Rauch-Tung-Striebel smoother. The simulation results show that the UPS effectively improves the estimation accuracy and this work offers a new off-line transfer alignment approach of distributed POS for multiantenna synthetic aperture radar and other airborne earth observation tasks.

MOLPOP-CEP: an exact, fast code for multi-level systems

We present MOLPOP-CEP, a universal line transfer code that allows the exact calculation of multi-level line emission from a slab with variable physical conditions for any arbitrary atom or molecule for which atomic data exist. The code includes error control to achieve any desired level of accuracy, providing full confidence in its results. Publicly available, MOLPOP-CEP employs our recently developed coupled escape probability (CEP) technique, whose performance exceeds other exact methods by orders of magnitude. The program also offers the option of an approximate solution with different variants of the familiar escape probability method. As an illustration of the MOLPOP-CEP capabilities we present an exact calculation of the Spectral Line Energy Distribution (SLED) of the CO molecule and compare it with escape probability results. We find that the popular large-velocity gradient (LVG) approximation is unreliable at large CO column densities. Providing a solution of the multi-level line transfer problem at any prescribed level of accuracy, MOLPOP-CEP is removing any doubts about the validity of its final results.