Design of a Three-phase Voltage Regulator Equipped with Voltage Balancing Technique

By Abdulkareem Mokif Obais
Department of Elect. Eng, College of Engineering
University of Babylon

Abstract
This paper presents a controlling strategy based on the addition of three reactive T-section circuitries
connected in series with a star-connected 3-phase load impedance. The left hand side branch of each Tsection
is a pure inductance having a constant reactance of +jX, while the right hand side impedance is a
pure capacitance having a constant reactance of –jX. The middle branch is a susceptance B, which is
composed of a switched capacitor bank in shunt with a switched inductor and is connected to the star point
of the load impedance. This susceptance is controllable in the range of ±Bmax. The system is capable of
maintaining the three-phase load voltage at its rated value even though the power system voltage is varying
within the range of 80% to 120% of its rated value. In addition, the system is equipped with voltage
balancing technique and is almost free from harmonics. The whole system was designed and implemented
using PSpice Program.