Abstract

Power transformers are very important and expensive components of electricity transmission and distribution networks. Though the failure rate of transformers is generally low, however, in the event of a failure, huge repair costs and long shutdown time are generally needed. The life of insulation decides the service lifetime of the transformers. Several oxidation inhibitors are generally inhibited into the oil in order to improve the lifetime. These inhibitors reduce the oxidation process inside the transformers insulation, and improve the dielectric strength. The present paper determines and compares the effectiveness of 1,2,3-benzotriazole and 2,6-dibutyl-4-methylphenol inhibitors on the oxidation degradation of mineral transformer oil subjected to higher accelerated thermal stresses. It improves the quality and the service lifetime of the insulation in transformers.

Abstract

This paper deals with the Major Power Quality problems like Voltage Flicker (VF) that occurs in a Power Industry. Industrial Arc Furnace (IAF) is the vital source for producing VF. It creates most significant Disturbance in electrical power systems dominantly in Distribution systems. The fast response of Custom Power device makes it a better solution for improving Power Quality in Distribution systems against the Non-linear loads like IAF. Due to the fastest growth in Semi-Conductors Industry and modern Techniques for development of Voltage Source Converters (VSC), FACTS Devices are used for Voltage Flicker Mitigation. The Voltage Flicker Compensation is done in 3 stages and analyzes the related results. Initially the Voltage Flicker mitigation using FCTCR (Fixed Capacitor Thyristor Controlled Reactor) was simulated. Secondly, the compensation for the Static Synchronous Compensator (STATCOM) has been performed. This paper presents a Instantaneous Reactive Power Controller technique for 6-pulse STATCOM to effectively compensate voltage flicker due to electric arc furnace load. In these cases, some major harmonic components are presented in the system, which can be minimized by using 12-pulse STATCOM. The obtained results show that STATCOM is an efficient solution for the Voltage Flicker Compensation. All the Simulations are done in the MATLAB Software.

Abstract

In the present time, applications of multilevel inverter devices are growing day-by-day in the industries due to many advantages. In the present work, the performance and analysis of multilevel inverters have been done in the latest MATLAB/Simulation environment. The performance of two and three level inverters has been compared and deduced that the three level inverter produces less harmonics as compared to two level inverter. Moreover, the analysis of multilevel inverters with different power semiconductor devices has also been done and concluded that the IGBT inverter gives most efficient results as compared to other power semiconductor devices. Since, the multilevel inverter fed devices produce large odd harmonics, especially fifth harmonics. Therefore, the high pass filter has been used to minimize harmonics to a significant level. Earlier, it has widely been observed that the transformer fed inverter devices produce large harmonics, therefore, in this work; an attempt has been made to reduce harmonics in these kind of devices and minimize harmonics to a significant level by active filters.

Abstract

The analysis and design process in large scale practical systems are computationally tedious because more number of variables are involved. Model reduction techniques are simplification methods based on physical considerations or by mathematical approaches employed to realize reduced models for the original high order systems. There are many reduction techniques available in the literature for single variable systems, but there are only few methods for reduction of multi variable systems. However, the methods related to single variable can be extended to reduction of linear Multi Input Multi Output (MIMO) systems. In this paper, a concept of interlacing property based on Hermite – Biehler theorem is discussed which includes the theory of interlacing of odd and even polynomials. In this method the denominator of MIMO system is reduced by interlacing property and reduced numerator is obtained by making use of matching of coefficients of higher order system. This method is applied for model reduction of 10^th order multi variable linear time invariant model of a power system. To prove the validity of the proposed algorithm, the performance indices and stability responses like settling time, overshoot, etc., are compared to that of the other existing methods.

Abstract

This paper presents the reactive power optimization and loss reduction in power system. This is a nonlinear, multivariable, multi-constrained problem, which makes the optimization process complicated. This work identifies the requirement of reactive power at a particular loading condition and optimized the same. To optimize the reactive power, MiPower software is used. The main objective of this work is to determine the quantum of compensation required to improve the voltage profile of low voltage pockets in the system and line loss reduction. MiPower model is simulated; results are tabulated and compared with analytical calculations for IEEE 14-bus system.

Abstract

The rapid development in computing resources has enhanced the performance of computers and reduced their costs. This availability of low cost powerful computers coupled with the popularity of the Internet and high-speed networks has led the computing environment to be mapped from distributed to Grid environments. Grid is a type of distributed system that supports the sharing and coordinated use of geographically distributed and multi- owner resources independently from their physical type and location in dynamic virtual organizations that share the same goal of solving large-scale applications. A computational grid is a hardware and software infrastructure that provides dependable, consistent, pervasive, and inexpensive access to high-end computational capabilities. Grid computing is concerned with “Coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations”. The key concept is the ability to negotiate resource-sharing arrangements among a set of participating parties (providers and consumers) and then to use the resulting resource pool for some purpose.

The sharing concern is not primarily file exchange, but rather direct access to computers, software, data, and other resources, as is required by a range of collaborative problem solving and resource-brokering strategies emerging in industry, science, and engineering. This sharing is, necessarily, highly controlled, with resource providers and consumers defining clearly and carefully just what is shared, who is allowed to share, and the conditions under which sharing occurs. A set of individuals and/or institutions defined by such sharing rules form what we call a virtual organization.