Simple equivalent permeability and reluctance models are obtained for the transformer core joints from the analysis of the magnetic flux. It is shown that the flux variations in the joint zone can be fitted with simple Gaussian expressions suitable for transformer design purposes. These models are derived from 2D and 3D finite element simulations. The magnetic flux distribution in the transform...

Energizing of large power transformers is considered a critical event in the operation of an electric power system. When a transformer is energized by the grid or utility, it takes very high value current known as inrush current, the typical value of this current could be ten times. This inrush causes many problems like mechanical stress on transformer & harmonics injection to generator winding...

Preventive maintenance in the transformer is performed through a differential relay protection system, and it protects from internal external faults. However, Current Transformer (CT) system mal-operates during inrush currents. CT saturates due to magnetizing currents causes false tripping of relays. Moreover, identification either current or faults needs be diagnosed. For above problem, contin...

The measurement of the current in industrial electrical devices is often carried out by current transformers. The reliability of these devices is compromised when the measured current is higher than the nominal value, due to the saturation and hysteresis effects of the magnetic core. In this paper, a nonlinear model of the current transformer is identified by means of a separable least squares ...

DC bias current flowing into the neutral point of power transformer will seriously affect the normal operation of AC power system. In this paper, exciting current, harmonic component of the excitation current, magnetic flux density and noise of transformer were analyzed when the transformer is in the no-load operation state based on field-circuit coupled method. Through the calculation and anal...

In this paper, a study has been carried out to analyze the factors influencing the current transformer (CT) saturation factor (KS), in particular the secondary time constant (TS) of a CT. The study identifies and analyzes the optimum value for TS as this value varies. This paper also analyses and discusses the effect of TS to the KS factor in order to calculate the CT knee point voltage (VK) in...

This paper proposes a new method to detect transformer inside incipient fault current using transformer internal parameters to determine the inside structure of transformer at good condition or bad. A transformer model was established by Jiles– Atherton theory using measured voltage and current and the initial parameters which were found using Genetic Algorithm (GA). Then, transformer internal ...