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 conventional high-frequency phase-shifted zerovoltage-switching (ZVS) full-bridge dc/dc converter has a disadvantage, in that a circulating current flows through transformer and switching devices during the freewheeling interval. Due to this circulating current, rms current stress, conduction losses of the transformer and switching devices are increased. To alleviate this problem, this pape...

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...

In this paper an analysis of different designs of traction transformers is given. The paper describes three-limb transformer design for 7.5 MVA and 10 MVA units and two-limb transformer design for 15 MVA and 16 MVA units. Paper also represents noise level measurement results and sound intensity frequency spectrum for 16 MVA unit. Based on results of measurements taken during heat run test on tr...

This paper presents an experimental investigation of transformer dielectric response and solid insulation water content. The dielectric response was carried out on the base of Hybrid Frequency Dielectric Spectroscopy and Polarization Current measurements method (FDS &PC). The calculation of the water content in paper is based on the water content in oil and the obtained equilibrium curves. A re...

Spiral inductors fabricated using a 90nm CMOS process have been characterized and analyzed. The extracted series resistance increases with frequency and temperature. The extracted resistance temperature coefficient exhibits a strong dependence on operating frequency. It gradually decreases with frequency and is different from the results using DC temperature coefficients. A single π-model is us...

Recently, dry power transformer (Dryformer) that performs one step transformation from transmission to distribution voltage levels, has been introduced [1]. The Dryformer (dry power transformer) combines the features of power transformer with that of station distribution transformer, by utilising XLPE insulated round conductor cable for winding construction. The parameters of the cable winding ...

A novel and useful millimeter-wave digitally controlled oscillator (DCO) that achieve a tuning range greater than 10% and fine frequency resolution less than 1 MHz. Switched metal capacitors are distributed across a passive resonator for tuning the oscillation frequency. To obtain sub-MHz frequency resolution, tuning step attenuation techniques are used that exploit an inductor and a transforme...

This paper proposes a transformer-assisted pulsewidth-modulation zero-voltage-switching neutral-pointclamped (NPC) inverter. With the assistance of a transformer-assisted small-rating lossless auxiliary circuit, the main switches work with zero-voltage switching without suffering from any voltage/current spikes, under simple explicit control. The technique allows for higher operating frequency ...

A photonic instantaneous frequency measurement system capable of measuring both RF frequency and power simultaneously, is conceived and practically demonstrated. This system employs an RF photonic Hilbert transformer together with low-cost, low-frequency photo-detectors to obtain two orthogonal DC measurements. This system exhibits a frequency range of 1-10 GHz. Wider frequency range can be ach...