Deenbandhu Chhotu Ram University: UPQC Application in 3P4W Systems

This report presents a detailed study on the application of a Unified Power Quality Conditioner (UPQC) in a three-phase four-wire (3P4W) distribution system, employing a dual control strategy. The project, conducted at Deenbandhu Chhotu Ram University of Science & Technology, focuses on improving power quality by mitigating issues caused by non-linear loads. The study involves analyzing load flow, sensitivity-based methods, and optimal power flow to verify the system's stability under load disturbances. The student's work encompasses the analysis of UPQC's series and parallel converters, addressing challenges like harmonic currents and voltage sags. The report highlights the engineering knowledge applied, including the understanding of real and reactive power control, and the innovative capability to regulate power flow. The project also identifies issues related to power quality degradation due to power electronics-based equipment and proposes solutions using active filters and UPQC to compensate for supply voltage issues. The report concludes with a review of the project's objectives, the student's contributions, and collaborative efforts.

Competency Demonstration Report
Career Episode 2

CE 2.1 Project Information
Name of the project: Study of unified power quality conditioner (UPQC) applied to
three-phase four-wire (3P4W) distribution systems using a dual control strategy
Location of the project: Sonepat, Haryana
Project Duration: January-May 2012
Organization: Deenbandhu Chhotu Ram University of Science & Technology
Role and Designation during the time: Electrical Engineer
CE 2.2 Project Background
CE 2.2.1 Characteristics of the project
I had conducted this work to study UPQC associated to the 3P4W system with use of
dual control strategy. Neutral current flows towards the series transformer are being
compensated by use of four leg voltage sources for shunt. At the operating conditions, series
transformer are neutral with virtual zero potential. The main characteristics of this project work
are to improve the power quality. Lower power quality is caused due to increase into nonlinear
loads generate lot of distortion at coupling points. The power devices draw reactive as well as
harmonic powers from supply due to its inherent nonlinearity. The distribution system provides
neutral conductor along with three power lines from the generated station.

CE 2.2.2 Objectives developed for the project
Following are the objectives for this project work:
 To improve the power quality by connection of series active power filter
 To focus approach towards analyzing flow of load and continuation power flow based
methods
 To verify capability of the system to stay behind stable below load disturbances
 To develop linear sensitivity features exploiting AC load flow approaches for bilateral as
well as instantaneous/multi transactions
 To observe Stability of the UPQC system, which includes the series and parallel
converters
CE 2.2.3 My Area of work
I had concerned into analyzing the demand of control quality improvement due to an
increment of non-linear loads associated to the electrical control system. I had determined UPQC
and utilized for controlling losses require understanding in implementation of the quality
controls. I had proposed that before going through modeling of UPQC, different methods are
required to analyze and apply such as optimal power flow, sensitivity based methods and load
flow and continuation power flow based methods for conducting the project study. I had verified
the capability of the 3P4W distribution systems which involve of series as well as parallel
converter. I had verified that the system is remaining stable under the load disturbances. I had
provided with unique capability of unconventionally regulating both real as well as reactive
power flow in the transmission line.

Prof. Tankeshwar Kumar
(Vice Chancellor)
Dr. JS Rana
(Dean of the Department)
Dr. SK Gupta
(Project Instructor and HOD)
Ruchi Verma
(M.tech Student)
CE 2.2.4 Project Group
Figure 1: People involved in the project
CE 2.2.5 My responsibilities throughout the project
I had implicited and conducted an-depth analysis on effectiveness of UPQC based 3P4W
distribution system. I had also analyzed dual implementation of dual compensation techniques. I
had conducted a study on UPQC system that consists of series and parallel converters. In order to
conduct the study, I had analyzed the series, parallel and hybrid active power filters. I had
focused my study on analysing the load current and continuance, optimal power flow based
methods, and sensitivity based methods plus dual compensation principle.

CE 2.3 Distinctive Activity
CE 2.3.1 Comprehending the Theory of the project
I had carried out the study on UPQC by employing to implement of dual compensation
strategy. It consisted of three-leg and four-leg PWM converter that shares the same DC link. I
had analyzed that UPQC is connected among 3P4W power supplying distribution system which
is composed of three phase as well as single phase loads. I had unspecified that a single phase
load is used of neutral conductor to function. 3P4W system is collected of three power
conductors as well as neutral conductor to be provided the loads. 3-leg split capacitor needs a
control loop in order to recompense inherent DC link capacitor voltage unbalanced. A 4-leg
converter includes of larger numeral of switches, power rated devices that composed that there is
reduction of 4th leg, as the current which flow throughout neutral conductor is low. As per the
dual compensation principles, I had to make input current as sinusoidal and balanced with utility
voltages. Based on dual control strategy, I had controlled series of PWM converter to operate as
sinusoidal current sources. I had also determined that a parallel converter can make output
voltage as sinusoidal and balanced with utility voltages. It is done to function of sinusoidal
voltage sources, such that impedance is sufficient to absorb low harmonic currents.

Figure 2: 3P4W distribution system base on UPQC topology
Series as well as parallel PWM converter consisted of high as well as low impedances, as
load harmonic currents are flowing throughout the parallel converter. I had ensured that
compensation for the load unbalanced is controlled the series converter to follow sinusoidal and
balanced. Reactive power compensation is controlled series converter current with utility
voltages. Dual control strategy is attractive as it considered load is fewer influenced by the
incidence of grid voltage turbulences, like the voltage sags.
CE 2.3.2 Engineering Knowledge and Skills applied in the project
I have awareness to analyze load flow as well as continuation and optimal power flow
based methods, sensitivity based methods as well as dual compensation principle. I have
capability to verify the system to make it stable under load disturbances. I have used of some
research methodology to develop linear sensitivity methods for utilization of AC load flow for
bilateral as well as simultaneous/multi transactions. I have innovative capability to regulate real
and reactive power flow into the transmission flow. I have used knowledge to understand real
and reactive power controlling with use of UPQC. My electrical engineer skills make it a
powerful device to access transmission system controls.
CE 2.3.3 Accomplishment and task performed
I had presented this project study by analyzing and implementing UPQC that is
connected to 3P4W distribution system to perform series and parallel power line conditioning. I
had conducted the work with use of dual control strategy. When the power system is available at
the plant site, then I had carried out UPQC power line compensation for installation of loads
need neutral conduction for operations. I had determined that series converter and parallel

converter are controlled as sinusoidal current and voltage sources respectively. The controlled
quality is sinusoidal as it reduces complexity into the algorithms used to calculate the
compensation references.
CE 2.3.4 Identified issues and their solutions
CE 2.3.4.1 Issues
Due to wide application of the power electronics based equipments, quality over the
power is becoming an issue into the project work. The use of conventional equipments for
enhancement of the power quality becomes inadequate. Power quality is affected by some of the
factors such as increase of non-linear loads and flickering of voltage as well as current. Those
factors will affect the operation of sensitive equipments and cause malfunction.
CE 2.3.4.2 Solutions
The problem is solved with help of active filters. This filter can solve random variables
problems into the load current as well as voltage waveform. For improvement over the power
quality issues, UPQC is used to recompense supply voltage power quality issues such as sags,
unbalanced, flicker plus load current quality issues.
CE 2.3.5 Plan to produce creative and innovative work
I had entailed of two consecutive, self-commutated, converters for voltage source, shunt
capacitor on the part of DC. I had noticed that single converter is attached to the AC system via
series transformer and the additional is attached to the AC system via shunt transformer. UPQC
circuit derived of stead state model. I had analyzed that the circuit is entailed of two ideal voltage
sources confirmed of the vital Fourier series constituent of switched voltage waveforms at the

AC converter terminal. The source impedance encompassed into the model has optimistic
sequence leakage inductances as well as resistances of the coupling controller of UPQC.
CE 2.3.6 Collaborative work
I had coordinated with the guide to work together and implemented a proper
communication and schedule plan. I was requested my guide Mr SK Gupta to provide feedback
on my project report that made me ensure that modeling of UPQC is done properly.
CE 2.4 Project Review
CE 2.4.1 Project overview
I had conducted this project work to analyze effective suppress of load harmonic currents,
compensate of load harmonics current and effective compensate of load reactive power. I had
analyzed the dual implementation of dual compensation technique for studying UPQC applied to
3P4W distribution system with use of dual control strategy. I had worked to improve the power
quality issues into power electronics devices by use of various methods, load flow in addition to
continuation and optimal power flow based methods, sensitivity based methods and others.
CE 2.4.2 My contribution to work
I had coordinated with the researchers and took their guidance to understand the project
work. I had analyzed the project to conclude on UPQC and exploit the similar for controlling the
losses under parameters require deeper devaluing into implementing the power quality controls.