In the power system voltage sag become the important issue for industries. According to the survey 92% of the interruptions at industrial installations are voltage sag related. In various companies voltage sag may affect many manufactures and introduce sufficient losses in the power system. The voltage sag compensator, based on a transformer coupled series connected voltage source inverter, is ...

A wind turbine transformer (WTT) is designed using a 3D wound core while the transformer’s total owning cost (TOC) and its inrush current performance realized as the two objective functions in a multi-objective optimization process. Multi-objective genetic algorithm is utilized to derive Pareto optimal solutions. The effects of inrush current improvement on other operating and design parameters...

During energisation of power transformers, transient inrush currents with peaks up to the short-circuit current may arise. Using controlled switching taking into account the residual flux, the transients can – in theory – be eliminated completely. Real factors such as closing time scatter and residual flux measurement uncertainty have to be considered when checking the suitability of controlled...

Second harmonic restraint is still commonly used to discriminate fault current and transformer inrush conditions. Such approach, however, has some disadvantages and limitations. Therefore various other criteria signals for power transformer inrush discrimination have been analysed. The paper presents a new multi-criteria stabilization algorithm that employs fuzzy reasoning technique for better ...

This research studies the forces on the windings of transformer due to inrush current. These forces are compared with the corresponding forces due to short-circuit of the windings. Twodimensional finite element computation of a single-phase shell-type transformer is carried out based on the maximum permissible inrush current value where its amplitude is the same as the rated shortcircuit curren...

the aim of this paper is to extend a hybrid protection plan for power transformer (pt) based on mra-ksir-ssvm. this paper offers a new scheme for protection of power transformers to distinguish internal faults from inrush currents. some significant characteristics of differential currents in the real pt operating circumstances are extracted. in this paper, multi resolution analysis (mra) is use...

When a transformer is energized the phenomenon of magnetizing inrush current occurs and causes a pseudo tripping signal to the differential relay which leads to the problem of mal operation or false tripping of the relay. In order to avoid this false tripping of the differential relay and for safe operation of the transformer the distinction of inrush current with internal fault current is very...

The aim of this paper is to extend a hybrid protection plan for Power Transformer (PT) based on MRA-KSIR-SSVM. This paper offers a new scheme for protection of power transformers to distinguish internal faults from inrush currents. Some significant characteristics of differential currents in the real PT operating circumstances are extracted. In this paper, Multi Resolution Analysis (MRA) is use...

The paper investigates the behavior of four transformer models in electromagnetic transients programs (EMTP) when calculating inrush currents due to shell-type transformers energization. These models are single-phase Saturable Transformer (STC), BCTRAN, Hybrid Transformer (XFMR) and UMEC. The measurements of a real transformer energization performed by EDF in France are used to evaluate the acc...