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Pamuk N.,Turkish Electricity Transmission Company | Uyaroglu Y.,Sakarya University
Scientific Research and Essays

Energy is one of the basic data for economic and social development. Sufficient electrical energy, high quality, continuous, low-cost and environmentally compatible manner should be available to consumers. Power system reliability depends on the reliability of the equipments in the system. For this reason, transformers of the power system are the most important equipments. In power transformer, failure rate is quite high compared to that in some parts of the world; and as such, the necessity to work in the best operation case of transformer and preventing transformer failures have obviously emerged. This study proposes the failure of insulating oil in power transformers. However, the electrical and thermal effects of cellulosic materials subjected to degradation have been analyzed in details and these gases emission show different type of failures. Also, these failures are seen in the production rate point to the magnitude of the failures. Analysis of failures using Fuzzy logic computer program have been tried in order to achieve the optimum method of evaluating the causes that play a role in the formation of probable transformer failures. © 2010 Academic Journals. Source

Power system equipment have conventionally used mineral oil for insulation and cooling. The preferable alloy material has to be generated with good chemical and electrical features. However, recent case has indicated the shortcomings of these fluids where they have poor characteristics particularly at fire and flash point and most significantly poor dielectric malfunction voltage. The most critical of these deficiencies is the disability to meet up with the environmental and health laws. Further, they are not organic and hence not biodegradable. In this study, natural palm oil and its derivatives have been studied in attempt to discover an environmental friendly insulating fluid. Patterns such as crude and refined palm oils were chemically and electrically tested and comparisons were made with the mineral oil. Electrical tests such as the malfunction voltage, power factor and resistivity were pursued. Besides that, chemical characteristics such as water content, kinematic viscosity, moisture content of the alloy, flash point, density, pour point, corrosion, neutralization value and dissolution of gases were also being investigated. Results from the test laboratory studies have indicated that the natural palm oil has preferable chemical and electrical features as compared to the existing mineral oil for power system equipment insulation. © 2015, Strojarski Facultet. All rights reserved. Source

Pamuk N.,Turkish Electricity Transmission Company | Uyaroglu Y.,Sakarya University
Energy Education Science and Technology Part A: Energy Science and Research

This paper deals with scenario of cascade failure in a large interconnected grid of Turkey. A single fault seldom leads to the catastrophe like blackout in energy system, but often causes other faults, which result in cascading failures and blackouts. Blackouts are occurred prevalently in huge energy system. Initiator events of these catastrophic failures can be prevented by convenient protection settings. In this study, different cascading failure scenarios are evaluated under credible contingency conditions. The scenarios have been analyzed on the Northwest Anatolia energy system with 118 buses where is the most critical part of Turkey Electricity System. The situation of energy plants and transmission lines in this energy system are analyzed for disability aspects. All energy system components are simulated by means of a power flow analysis performed with the PSS/E software. The power flow map is drawn from simulated data. The results allow us to be better prepared to face these severe disturbances, defining procedures for emergency situation and training the control room operators. © Sila Science. Source

Pamuk N.,Turkish Electricity Transmission Company | Uyaroglu Y.,Sakarya University
Elektronika ir Elektrotechnika

In this paper, an approach of power system fault diagnosis model based on Petri Net (PN) is proposed. The construction of diagnosis model and the method of identifying the faulted components are described in detail. The detailed PN models and relevant conclude process are presented. The proposed system can spot the fault components fast and exactly, and constitutes reliable and impressive diagnosis results automatically. It can be applied in the power system for not only simple fault, but also multiple faults or the violent faults are made up of the protective devices false operation. This system is good for the fault diagnosis of power system. It shows that the fault diagnosis system based on the proposed models is practicable and impressive. Source

In electrical power system, variety of solid, liquid and gaseous materials are used for insulation target to protect the incipient failure inside the high voltage power transformers. The insulation is practically ended when the insulation system has become fragile enough to flourish cracks under the electrical and mechanical stresses to which it is subjected. The electrical and mechanical stresses are induced by short circuit currents, thermal expansion and contraction of the conductors and vibration. The dielectric strength of insulation is not vitally diminished by brittleness alone, but electrical breakdown will rapidly follow the improvement of ensuing cracks. The purpose of this paper is to briefly cover the methods favourable for determining the insulating value of the insulation on high voltage power transformer windings and bushings. Many failures of insulation are caused by the entrance of moisture. Insulating materials used on high voltage power transformer windings have a high affinity for moisture from the surrounding atmosphere or oil. Effects of the stressed oil volume and stressing time on the breakdown stress of high voltage power transformer insulation were experimentally investigated. The factors influencing the effects and the results obtained based on them were statistically analysed and systematized by the Weibull distribution method. A Four-dimensional volume theory allowing good estimation of breakdown stress in terms of specific probable values has been established. Source

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