This paper presents the three topologies of three-phase four-wire DSTATCOM for reduction of harmonics, reactive power compensation, increasing power factor, which occur due to a nonlinear load, environment problem and polluted grid. The performances of the above topologies have been compared for the magnitude of source current, power factor improvement, DC-link voltage regulation, and total har...

As an important equipment, voltage transformer is widely used in power grid to obtain signal and protect the system. In this paper, transformers system are classified according working principle. The principle characteristics of potential (PT), capacitor (CVT), electronic (EVT) optical transducer (OVT) briefly analyzed. Besides, paper also introduces principle, category transformer, as well app...

This paper presents an experimental investigation of transformer dielectric response and solid insulation water content. The dielectric response was carried out on the base of Hybrid Frequency Dielectric Spectroscopy and Polarization Current measurements method (FDS &PC). The calculation of the water content in paper is based on the water content in oil and the obtained equilibrium curves. A re...

The steady-state oscillation of a zero-voltageswitching clamped-voltage self-oscillating ballast driven by a saturable transformer is analyzed and simulated. Its selfoscillating operation is divided into six stages according to the hysteresis B–H loop of saturable transformer cores. Stage-wise circuit analysis shows the saturable transformer limits the lamp current and dominates the switching f...

This paper presents a transformer less ac/dc converter which can be used in voltages between 90230 Vrms. Instead of a transformer, this topology consists of a buck dc/dc converter and a buck boost dc/dc converter. By the absence of transformer, reduce the complexity of converter and it is cost effective. Buck dc/dc converter keeps o/p voltage below the line voltage; limit the leakage current. B...

Ferroresonance is a highly destructive power quality phenomenon caused by complex oscillations generated by nonlinear magnetizing inductances in ferromagnetic materials and capacitive elements in power systems. In an effort to better understand ferroresonance and predict bifurcations and responses, an improved nonlinear transformer model for dynamic and steady-state operating conditions is deve...

A new topology of unified power quality conditioner (UPQC) is proposed for different power quality (PQ) improvement in a three-phase four-wire (3P-4W) distribution system. For neutral current mitigation, a star-hexagon transformer is connected in shunt near the load along with three-leg voltage source inverters (VSIs) based UPQC. For the mitigation of source neutral current, the uses of passive...

This paper describes role of UPQC as applied to a 3P4W system to improve PQ. The Forth wire of 3P4W system is developed by means of neutral of series transformer. Neutral current which flows through neutral terminal of transformer is removed with the help of 4 leg voltage source inverter (VSI) topology for shunt part. The series transformer neutral will have 0 potential in all conditions of ope...