High-frequency current transformers (HFCT) are well suited as sensors for measuring transient signals on power cables, such partial discharges (PD). If the HFCT is designed and its measurement bandwidth matches of signal to be measured, high sensitivities can achieved. However, optimizing design a specific difficult task because various parameters affect transfer function. In addition, there li...

Intelligent Universal Transformer (IUT) is a key point introducing as an Intelligent Electrical Devices (IED) for Advanced Distribution Automation (ADA) in future. ADA is the state of art, comprising flexible electrical architecture contributed with open communication construction for the tomorrow’s distribution automation. IUT is based on a power electronic transformer employing the new techno...

This paper presents a novel power transformer differential protection scheme by using combined Wavelet Transform and Artificial Neural Network which provide the means to enhance the classical protection principles and facilitate faster, more secure and dependable differential protection for power transformer. Wavelet transform is used to extract the feature from transient signal and the neural ...

Transient overvoltages appearing at line terminal of power transformer HV windings can cause failure of winding insulation. The failure can be from winding to ground or between turns or sections of winding. In most of the cases, failure from winding to ground can be detected by changes in the wave shape of surge voltage appearing at line terminal. However, detection of insulation failure betwee...

Eliminating the leakage current is one of most important issues for transformer less inverters in grid connected photovoltaic applications. The technical challenge is how to keep the common mode voltage constant to reduce the leakage current. For this purpose an improved single phase transformer less inverter is proposed. It has two additional switches connected in the dc side. The PWM pulses f...

An original electronic device for compensating ratio and phase-displacement errors, of measuring current transformers and clamp-on probes, is proposed. It is specially intended for low-frequency applications (power frequency and its harmonic components), where the magnetizing current is the main cause of measuring errors. This system reduces the magnetic flux in the transformer core, reducing i...

Many industrial and commercial sensitive loads are subject to the voltage sags and interruptions. The static transfer switch (STS) based on the thyristors is applied to improve the power quality and reliability. However, the transfer will result in severe inrush current in the load transformer, because of the DC component in the magnetic flux generated in the transfer process. The inrush curren...