Placement of Distributed Generation for Improvement of Voltage Profile in Distribution System

Distributed Generation is an approach that employs small-scale technologies to produce electricity close to the end users of power.When total system load is more than its generation capacity that makes relieving of load on the feeders not possible and hence voltage profile of the system will not be improved to the required level. In order to meet required level of load demand, DG units are integrated in distribution network to improve voltage profile, to provide more reliable and less uninterrupted power supply. Voltage stability is an important problem in the emerging world of technologies and development, the main objectives in operating an electric power system is to maintain a proper voltage level thought DG. Voltage Stability Index method is to be used for determining DG placement candidates. A Voltage Stability Index method is to be executed on the system and the bus with a minimum voltage at the collapse point is defined as the most sensitive bus to voltage collapse. This bus is to be selected as a candidate for DG placement

Detection of gamma-ray quasi-periodic oscillations in non-blazar AGN PKS 0521-36

Quasi-periodic oscillations (QPOs) have been detected in many Fermi-detected bright blazars. In this letter, we report multiple QPOs detected in a non-blazar AGN PKS 0521-36 searched over the entire 15 years of Fermi-LAT data. QPOs are detected at 268 days, at 295 days, and at 806 days timescales with more than 3$\sigma$ significance. The QPO detected at 806 days happens to be the third harmonic of QPO at 268 days. The time scales are consistent in both Lomb-Scargle and Wavelet analysis. Furthermore, the Gaussian Process modeling of the light curve is performed with stochastically driven damped harmonic oscillator (SHO) and damped random walk (DRW) modeling to uncover the presence of QPOs. The constructed power spectral density (PSD) exhibits two QPOs, with observed timescales of approximately 283 days and 886 days. This is the first non-blazar AGN where the long-term QPO is detected. Earlier studies show this source has a weak beamed jet. The exact cause for these QPOs remains unclear. We also assembled the $\gamma$-ray QPO detected in various blazar and tested the QPO time scale dependent on the black hole mass. No significant correlation is found.Comment: 10 pages, 7 figure

Regular charged black hole in massive gravity as heat engine

We examine the effect of addition of graviton mass on the efficiency of a regular charged black hole (RCB). In doing so, we make few comments on the critical behaviour of the system and calculate the relevant thermodynamic quantities such as entropy, Hawkings temperature and heat capacity. We confirm that graviton mass has a positive effect on the efficacy of such a heat engine under consideration