Magnetic core saturation of transformers and rotating machines generate harmonics. Harmonics are integer multiples of the fundamental frequency. Harmonics is caused by nonlinear devices in the power system. Due to the non-linear loads, power frequency harmonics exist mainly in distribution systems. The current harmonics cause voltage harmonics, hence resulting in nonsinusoidal supply voltage in...

Modeling of power distribution transformers in the high-frequency range is of crucial importance in cases such as using power-line communication technology or investigating transient overvoltages at the transformer low-voltage side. This paper presents a simple black-box modeling methodology for distribution transformers using transfer functions defined by the recorded voltage ratios at the tra...

In this paper, multilayered coreless printed circuit board (PCB) step-down power transformers for DC-DC converter applications have been designed, manufactured and evaluated. A set of two different circular spiral step-down transformers were fabricated in the four layered PCB. These transformers have been modelled with the assistance of high frequency equivalent circuit and characterized with b...

A method for testing electronic instrument transformers is described, including electronic voltage and current transformers (EVTs, ECTs) with both analog and digital outputs. A testing device prototype is developed. It is based on digital signal processing of the signals that are measured at the secondary outputs of the tested transformer and the reference transformer when the same excitation s...

power transformers are key components in electrical power supplies and their failure could cause severe consequences on continuity of service and also generates substantial costs. identifying problems at an early stage, before catastrophic failure occurs, is a great benefit for reliable operation of power transformers. frequency response analysis (fra) is a new, well-known and powerful diagnost...

Transformer insulating oil nanofluid is made to improve dielectric and thermal properties of the oil by employing nanoparticles with proper properties. In the current work, nanofluids based on transformer mineral oil were prepared by three procedures using diamond nanoparticles with high thermal conductivity, as well as high dielectric properties. It was tried to consider the impacts of surfact...

Transformers are normally designed and built for use at rated frequency and perfect sinusoidal load current. A non-linear load on a transformer leads to harmonic power losses which cause increased operational costs and additional heating in power system components. It leads to higher losses, early fatigue of insulation, premature failure and reduction of the useful life of the transformer. To p...

An improved transformer coupled gate driver scheme for high speed switching applications in power supply or motor drive is proposed in this paper. It improves the deficiencies caused by the conventional transformer coupled gate driver scheme, such as oscillation of the output PWM signal that will make MOSFET improper turn-on, when the duty cycle of input PWM signal reduces from large value to s...

One of the most critical components in a step-up design like Figure 1 is the transformer. Transformers have parasitic components that can cause them to deviate from their ideal characteristics, and the parasitic capacitance associated with the secondary can cause large resonating current spikes on the leading edge of the switch current waveform. These spikes can cause the regulator to exhibit e...

Theoretical research and equipment development of traveling-wave fault location seriously depend on digital simulation. Meanwhile, the fault-generated transient traveling wave must be transferred through transmission line, mutual inductor and secondary circuit before it is used. So this paper would maily analyze and summarize the modeling technology of transmission line and mutual inductor on t...