Improved Step Response of Power System Stabilizer using Fuzzy Logic Controller

As every power system is constantly being subjected to disturbances, we should see that these disturbances do not make the system unstable. Therefor additional signals derived from speed deviation, excitation deviation and accelerating power are injected into voltage regulators. The device to provide these signals is referred as power system stabilizer. The use of power system stabilizers has become very common in operation of large electric power systems. The conventional PSS which uses lead-lag compensation, where gain settings designed for specific operating conditions, is giving poor performance under different loading conditions. Therefore, it is very difficult to design a stabilizer that could present good performance in all operating points of electric power systems. In an attempt to cover a wide range of operating conditions, Fuzzy logic control has been suggested as a possible solution to overcome this problem. In this paper, a systematic approach to fuzzy logic control design is proposed. The study of fuzzy logic power system stabilizer for stability enhancement of a single machine infinite bus system is presented. In order to accomplish the stability enhancement, speed deviation and acceleration of the rotor synchronous generator are taken as the inputs to the fuzzy logic controller. These variables take significant effects on damping the generator shaft mechanical oscillations. The stabilizing signals were computed using the fuzzy membership function depending on these variables. The performance of the system with fuzzy logic based power system stabilizer is compared with the system having conventional power system stabilizer and system without power system stabilize

Administration of Stabilized Flyash Stratum in Flexible Pavements

Expansive soils are major source of heave stimulated structural agony. Swelling of expansive soils cause grave problems and create damage to structures. Extensive work has been carried out on waste materials concerning the feasibility and environmental suitability. Flyash, a waste byproduct from coal burning in thermal power stations is bountiful in India causing health, environmental and dumping problems. Stabilization process with model test tracks over expansive subgrade in flexible pavements is one of the solutions. Cyclic plate load tests along with heave measurements are carried out on the tracks with chemicals like lime and cement introduced in flyash subbase laid on expansive subgrades. Test results show that maximum load carrying capacity is obtained for treated alternatives compared to untreated alternatives. Keywords: Expansive soil, Flyash, Lime, Cement,Flexible pavemen

Effect of Alkaline Treatment on Mechanical and Thermal Properties Oftypha Angustifolia Fiber Reinforced Composites

Sustainable development is increasingly becoming a priority of governments and businered which is driven by growing environmental awareness. Much academic research explores new ways to create greener and environmentally friendlier materials for variety of aplications ranging from aeronautic, automotive and construction industry. The natural fibre reinforced composite has the advantage of being light weight, availability, strong, cheap, safe, ease of recycling, sustainability, renewability hermal and acoustic insulation, saving of fabrication energy and carbon dioxide neutrality. The composites are molded with unsaturated polyester resin matrix and reinforced with natural fibre. Five identical specimens are prepared for each fibre content. In this study, mechanical properties of composite such as tensile strength, tensile modulus were measured using universal testing machine. Guarded hot plate apparatus was used to measure the thermal conductivity of natural fibre typha angustifolia reinforced composite.. The results shows that mechanical properties, increased as fiber content increased. Thermal conductivity of composite is in the range of 0.168 w/m k to 0.187 w/m k and thermal conductivity decreased about 11.3% as fiber content increased. The newly developed composite material has lower thermal conductivity and is used as an insulating material to save energy

PERFORMANCE STUDY OF FLEXIBLE PAVEMENTS ON NON EXPANSIVE SOILS

As part of infrastructure development   huge investment is being made on expansion of National highways and important roads across the country.  For improvement of Highways two types of Pavements are commonly used in India viz., Flexible Pavements (Bituminous) and rigid pavements (Concrete). Flexible pavements are widely used in this country from the considerations of economy The performance of Flexible pavements depends largely on properties of original ground on which the pavement rests, the quality of materials used in the construction of various layers of pavement and quality assurance as per relevant specifications. In general any road after construction is basically evaluated by the performance in terms of unevenness index and structural stability over a period of time. The evaluation of these two important parameters will facilitate the clear understanding of performance of various materials used in the construction and to undertake suitable rehabilitation measures if necessary. Keywords: Expansive Soil, Flexible Pavement

Performance Evaluation of Hybrid Precoder Design for Multi-User Massive MIMO Systems with Low-Resolution ADCs/DACs

This paper presents a comprehensive analysis and design of a hybrid precoding system tailored for mmWave multi-user massive MIMO systems in both downlink and uplink scenarios. The proposed system employs a two-stage precoding approach, incorporating UQ and NUQ techniques, along with low-resolution DACs in downlink and ADCs in uplink to address hardware limitations. The system considers Zero Forcing and Minimum Mean Square Error algorithms as digital precoding methods for the uplink scenario, while exploring the impact of different DAC resolutions on system performance. Extensive simulations reveal that the proposed system surpasses conventional analog beamforming methods, particularly in multi-user scenarios involving inter-user interference. In downlink, the system demonstrates a trade-off between SE and EE, achieving higher Energy Efficiency with NUQ. In uplink, NUQ and UQ converters exhibit similar performance trends regardless of the chosen combiner algorithm. The proposed system attains enhanced Spectral and Energy Efficiency while maintaining reduced complexity and overhead. The study significantly contributes to the advancement of efficient and effective mmWave multi-user massive MIMO systems by providing a thorough analysis of various quantization schemes and precoding techniques. The findings of this research are expected to aid in the optimization of 5G and beyond technologies, particularly in high-density deployment scenarios

Synthesis of Dinaphtho-dioxaphosphocin-8-oxides, Epoxides and Bisphosphonates

Preparation of 8-substituted-16H-dinaphtho [2,1-d:1’,2’-g] [1,3,2] dioxaphosphocin 8-oxides (5a–g) with an eight-membered phosphorus heterocyclic system (2) and their epoxides and bisphosphonates was accomplished by reacting 8-bromo-dinaphthophosphocin (2) with different mono and bis Grignard reagents (3a–g and 6) followed by oxidation with H2O2. Their structures were confirmed by elemental and spectral (1H, 13C and 31P NMR) data analysis. Some of these compounds are found to possess moderate antimicrobial activity.KEYWORDS: Dioxaphosphocin 8-oxides, dioxaphosphocin bisphosphonates, antimicrobial activity

Performance of Wind Farm Employing Type-4 Wind Turbine with D-Statcom

Wind power is environmentally friendly and cost-predictable nature. It is widely recognized as a promising alternative electric power generation source at a time of uncertain fossil fuel costs and concern over the harmful effects of climate change. Various problems arise due to the rapid injection of wind power in the electrical grid, affecting the power quality. Harmonics and various power quality problems like voltage sag and swell are of common occurrence due to the voltage injected by the wind generators in the electrical grid. These may result into severe problems such as system frequency mismatch and change in power line capability. To reduce such problems a distributed static compensator (DSTATCOM) is employed.  The DSTATCOM is an effective way of reducing power quality problems, removing the wind speed fluctuations and improving the transient stability of wind farm. Simulation results show the proposed effectiveness of wind farm stability and power quality. The generating system is modeled and simulated in MATLAB environment using Simulink and Simpower System toolboxes. Keywords: Wind Farms (WF), Wind Energy, Distributed static compensator (DSTATCOM