Date of Graduation

5-2016

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering (MSEE)

Degree Level

Graduate

Department

Electrical Engineering

Advisor/Mentor

Juan C. Balda

Committee Member

Alan Mantooth

Second Committee Member

Roy McCann

Keywords

Applied sciences, Electric distribution systems, Negative-sequence currents, Shunt compensator, Unbalanced compensation, Zero-sequence currents

Abstract

The objective of this thesis is to present the theory, design, construction, and testing of a proposed solution to unbalanced current loading on three-phase four-wire systems. The Unbalanced Current Static Compensator is the name of the prototype; herein referred to as the UCSC. The purpose of this prototype is to redistribute current between the three phases of a distribution system. Through this redistribution, negative- and zero-sequence currents are eliminated and a balanced system is seen upstream from the point of installation.

The UCSC consists of three separate single-phase H-bridge inverters that all share the same dc-link capacitor. Each of these inverters performs independently using a single-phase rotating reference frame controller. Each either draws or injects current onto the distribution system lines to balance the active currents and performs power factor correction for voltage compensation. A 34.5 kV, 6 MVA system was built and simulated in Matlab/Simulink™ to test the validity of this solution. A scaled-down UCSC prototype was then designed and constructed to compensate for a 208 V, 10 kVA system. Results from both the simulations and testing of this UCSC prototype are presented and analyzed.

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