Significance: Dec 29, 2001 Identified By: NRC Item Type: FIN Finding DEGRADED AND INADEQUATELY TESTED TRANSFORMER AND PROTECTIVE RELAYING RESULTS IN INCREASE IN TRANSIENT AND LOSS OF OFFSITE POWER INITIATING EVENT FREQUENCIES On August 2, 2001, Unit 2 experienced a transformer failure, reactor scram, and loss of offsite power. The inspectors determined that a lightning strike in conjunction wit...

The Hot Spot Temperature (HST) value depends on the ambient temperature, the rise in the top oil temperature (TOT) over the ambient temperature, and the rise in the winding HST over the top oil temperature. In this paper a new semi-physical model comprising of the environmental variables for the estimation of HST and loss of insulation life in transformer is proposed. The winding hot-spot tempe...

Power transformers are one of the most critical devices in power systems. It is responsible for voltage conversion, power distribution and transmission, and provides power services. Therefore, the normal operation of the transformer is an important guarantee for the safe, reliable, high quality and economical operation of the power system. It is necessary to minimize and reduce the occurrence o...

Original scientific paper Measurement of grid voltage harmonic components is an important part of power quality measurements. Current high voltage transformers with iron core are not linear and cannot easily be used for accurate measurement of "polluted" voltages in wide frequency range. In this paper, design details of a new coreless voltage transformer for power quality measurement are given....

Abstract: Power transformers are one of the most important electrical equipment that are used in power transmission system as they perform the function of transforming the voltage levels. Hence maintenance of power transformer is mandatory; as they are located at different geographical areas periodical monitoring is not possible all the time due to insufficient man power. Due to this reason tra...

Power transformers are important and expensive components in the electric power system. The knowledge of the actual status of the transformer insulation behavior, load tap changer performance, temperature, and load condition is necessary in order to evaluate the service performance concerning reliability, availability and safety. Systems abnormalities, loading, switching and ambient condition n...

With the rapid development of power electronics technology, the applications of inductively coupled power transfer make the wireless power transmission reality. In order to explore the practical application in the field of ICPT, we analysis the core component of a loosely coupled transformer of ICPT and design it. We make a model and simulate the core magnetic field distribution of the loosely ...

A Class-E/Fodd high power amplifier (PA) using the distributed active transformer (DAT) is demonstrated at 29MHz. The DAT combines the output power from four VDMOS push-pull pairs. The zero voltage switching (ZVS) condition is investigated and modified for the Class-E/Fodd amplifier with a non-ideal output transformer. All lumped elements including the DAT and the transistor package are modeled...

Power transformer is one of the most critical and expensive components in power grid which occupies almost 60% of total investment. Due to the expensiveness of power transformer investments, monitoring and maintenance of transformer condition are the important tasks in the field. There exist various diagnostic methods to monitor transformer health condition in the literatures. However, these me...

In order to analyze the leakage magnetic field and stray loss in power transformer, leakage magnetic field and stray loss in structure parts of a power transformer are calculated by three-dimensional (3-D) non-linear time harmonic finite element method (FEM). The results show that stray loss and loss density in structure parts are large and which may lead to local overheating and affect perform...