Based on the analysis of operation principles of conventional self-exciting electronic ballast, the cause of high switching loss has been researched. In order to reduce switch temperature and increase the reliability of the whole circuit, drive circuit of self-exciting electronic ballast has been improved to achieve soft switch. Circuit simulations and experimental results are coincided with th...

Power transformers with superconducting windings need a protection system to prevent damage to the low-loss superconducting winding by an abnormally high current. The generally accepted protection technique which uses auxiliary coils has been analysed using a network representation. The current distribution between main and auxiliary coil is expressed in terms of geometrical parameters. Experim...

In this paper, a new evolutionary approach has been discussed for reactive power dispatch (loss reduction) with the contribution of particle swarm optimization. Proposed algorithm has been applied to achieve the major objective as the system loss minimization with satisfied equality and inequality constraints. Tap settings of transformer, voltage at generator bus and shunt capacitor banks have ...

In High Voltage Direct Current Transmission (HVDC) system, converter transformer (CT) is an essential part of the system. Losses that occur in CT are copper loss, stray and core loss. The loss occurs transformer's metallic parts, such as tank, which 10% to 15% total flowing through non-sinusoidal current, so more losses produced than normal power transformer. this paper, horizontal wall shunt u...

This thesis describes how to provide standardized, current based, differential protection for any three-phase power transformer, including phase-shifting transformers with variable phase angle shift and transformers of all construction types and internal on-load tap-changer configurations. The use of standard transformer differential protection for such applications is considered impossible in ...

this paper proposes a flexible power electronic transformer (fpet) for the application in the micro-grids. the low frequency transformer is usually used at the point of common coupling (pcc) to connect the low voltage grid and utility network to each other. the conventional 50hz transformer results in enhanced low voltage-grid power management system during grid-connected operation. in this pap...

Among the most noticeable root causes of improper performance in power transformers, internal short circuit faults can be noted and if not quickly be identified and addressed in the accepted time interval, irrecoverable damages such as interruption or even collapse of the network connected to the power transformer would happen. In this contribution, three-phase transformer behaviors under magne...

This study reports the preparation of soft magnetic ribbons of Fe-based amorphous alloys using the single-roller melt-spinning technique. Ribbon width varied from 142 mm to 213 mm and, with a thickness of approximately 22 μm 2 μm. The microstructure and magnetic properties of the ribbons were characterized by differential scanning calorimeter (DSC), X-ray diffraction (XRD), vibrating sample mag...

We present a method and a software tool, the FrameNet Transformer, for deriving customized versions of the FrameNet database based on frame and frame element relations. The FrameNet Transformer allows users to iteratively coarsen the FrameNet sense inventory in two ways. First, the tool can merge entire frames that are related by user-specified relations. Second, it can merge word senses that b...