Reliability of a power system is considerably influenced by its equipments. Power transformers are one of the most critical and expensive equipments of a power system and their proper functions are vital for the substations and utilities. Therefore, reliability model of power transformer is very important in the risk assessment of the engineering systems. This model shows the characteristic...

A frequency domain filtered-x type least mean active sound intensity adaptive control algorithm based on waveform synthesis is developed for active control of transformer noise. The algorithm is useful for providing global control of transformer noise by minirnising the mean active sound intensities for the fundamental frequency and its harmonics in the near acoustic field of the transformer. M...

In this paper, a 24 GHz transformer-coupled VCO is presented for a wide linear tuning range in the 0.13-μm CMOS process. The measured results of the proposed VCO show that the center frequency is 23.5 GHz with 7.4% frequency tuning range. The output frequency curve has wide linear tuning region (5.5%) at the middle of the curve. Also, the VCO exhibits good phase noise of −110.23 dBc/Hz at an of...

Lumped Parameter Model is well known in solving high frequency signal propagation in high voltage transformer windings. At Southampton University, the modelling technique has been improvised and employed to solve partial discharge (PD) problem occurred within deep inside transformer windings. Firstly, a lumped capacitive parameter model was considered and secondly a transmission line lumped par...

Recent analysis and experiments have demonstrated the potential for transmission line transformers to be employed as compact, high-frequency, high-power, pulsed oscillators with variable rise time, high output impedance, and high operating efficiency. A prototype system was fabricated and tested that generates a damped sinusoidal wave form at a center frequency of 4 MHz into a 200 Omega load, w...

Inrush current is a very important phenomenon which occurs in transformer during energization at no load. It depends on several factors like magnetizing properties of magnetic material, resistant and inductance of primary winding, supply frequency, switching angle of circuit breaker, applied voltage etc. Objective of this study is to estimate the maximum value of transformer inrush current. Mea...

Design of Converter transformer insulation is a major challenge. The insulation of these transformers is stressed by both AC and DC voltages. Particle contamination is one of the major problems in insulation structures, as they generate partial discharges leading it to major failure of insulation. Similarly corona discharges occur in transformer insulation. This partial discharge due to particl...

Well known reasons for local failures in power transformers are caused by partial discharges (PD) in the electric insulation. Continuous deterioration over time increases the defect which finally can lead to a breakdown of the entire insulation. The importance of PD measurement is accommodated by standardized electrical measurement according to IEC 60270 [1] which is required for acceptance cer...

Abs t rac t -The phys ica l s ize of inductors in resonant converters was examined i n terms o f inductor t o transformer s i z e rat io . F o l l o w i n g the general d i scuss ion o f the i s s u e , the inductor s i z e i n ser i e s resonant DC-DC converter i s examined i n deta i l . It i s shown that the inductor t o transformer s i z e rat io i s a funct ion of the peak v o l t a g e o ...

A circuit configuration of a single-phase nonisolated online uninterruptible power supply (UPS) with 110-V/220-V input–output voltage ratings is proposed, allowing the bypass operation without a transformer even if the input voltage is different from the output voltage. The converter consists of an ac–dc/dc–dc three-level boost converter combined with a double half-bridge inverter. In this type...