Electric power industry is extensively using gas-insulated systems for the transmission and distribution of electrical energy. In high-voltage technology, the gas insulation is dominated by Sulphur-hexafluoride (SF 6) since the early 60th. It is a greenhouse gas and has long atmospheric lifetime. This paper proposes comparatively more environmental friendly R410 gas as an alternative to SF 6 for high-voltage applications. To validate the performance and theoretical concepts, it has been analysed experimentally. Buffer gases air and carbon dioxide were mixed with the base gas R410A to reduce the liquification temperature and global warming potential. Dielectric strength of R410A was tested for DC as well as AC voltage, results were compared with that of SF 6 and other alternatives available in literature, and the results were comparable. Insulation selfrecoverability test of R410A was performed and the synergistic effect of the mixed gases was calculated. Consequently, this work has discovered that R410A is the suitable alternative to SF 6 for high-voltage applications.
A novel dual‐band MIMO dielectric resonator antenna with high port isolation for WiMAX and WLAN applications is designed and investigated. The proposed antenna operates at 3.5 and 5.25 GHz bands. High port isolation is achieved using hybrid feeding mechanism that excites two orthogonal modes at each frequency bands. The measured impedance bandwidth of the proposed antenna covers the entire WiMAX (3.4–3.7) GHz and WLAN (5.15–5.35) GHz bands. The scalable behavior along with the frequency ratio of the antenna has also been investigated in this work. The measured isolation between antenna ports is −52 dB at the lower band and −46 dB at the upper band, respectively. Envelope correlation coefficient, diversity gain and mean effective gain have also been investigated. Moreover, measured results are in good agreement with the simulated ones.
Abstract-In this paper, a dual-band multiple-input multiple-output dielectric resonator antenna (DRA) with pattern diversity is presented. L-shape of the DRA produces patterns diversity at the lower band whereas, at the upper band, it is caused by exciting T E x 121 /T E y 211 mode in the DRA. Two copper strips are pasted at the corner of the dielectric radiator to improve matching at both the bands. A cylindrical air-gap introduced in the radiator improves isolation up to 25 dB and 20 dB at lower and upper frequency bands, respectively. The MIMO system possesses pattern diversity and isolation without applying any special decoupling technique. The design covers the WiMAX and WLAN bands at 3.6 and 5.2 GHz, respectively. Simulated and measured reflection coefficients, envelope correlation, diversity gain and mean effective gain, are in good agreement.
In Pakistan, the performance of conventional electrical grids is inefficient, resulting in severe energy crises. To overcome the alarming challenges persisting in the energy grids, Pakistan must focus on system protection, grid reliability, distribution and transmission, and power quality. The inefficiencies in grid protection and management signify an overall problematic energy scenario. The solutions to these problems include the improvement of domestic, commercial, and industrial demand-side management and the reduction in distribution network losses. A smart grid (SG) is a critical requirement as it can overcome the shortcomings of the existing grid owing to its promising features, enhanced consumer empowerment, utmost security; efficient and optimized energy flow; and demand-supply management. Thus, the SG is essential to overcome the energy crisis in Pakistan and achieve the standards of other developed nations in the energy sector. This study aims to highlight the significant prospects of SGs within Pakistan with the key objectives of its availability requirements. We compare the energy scenario in Pakistan with that of other countries and recommend various aspects that require improvement through SG implementation. Additionally, we discuss the incorporation of renewable energy resources and present a market analysis regarding SGs to illustrate the SG scenario and its implementation in Pakistan. Moreover, we analyze and evaluate detailed taxonomies of energy generation, energy projects, renewable energy assessment, power market trends in Pakistan, and the basic requirements of SGs. Furthermore, a critical analysis of the energy sector in Pakistan is elaborated, which describes the possibilities, requirements, and strengths pertaining to the transformation of the modern electric grid with respect to the China-Pakistan Economic Corridor. Thus, we believe that our work is more versatile in improving the energy system of Pakistan for the implementation of the SG.
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