Banca de QUALIFICAÇÃO: Victor do Prado Brasil

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Victor do Prado Brasil
DATE: 23/12/2022
TIME: 08:00
LOCAL: Virtual
TITLE:

A Study on Power Factor Billing Fairness Under Unbalanced and Nonsinusoidal Voltage Supply

KEY WORDS:

Power Factor, Harmonic Distortion, Voltage Unbalance, Induction Motor.

PAGES: 69
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Sistemas Elétricos de Potência
SPECIALTY: Medição, Controle, Correção e Proteção de Sistemas Elétricos de Potência
SUMMARY:

Voltage unbalance and harmonic distortion have several undesired effects on the grid-connected
equipment, especially induction motors. However, there is not yet a consensus regarding the correct
power-related definitions, such as reactive power and power factor (PF), as well as their appropriate
measurement methods when the voltage is unbalanced or nonsinusoidal. As a result, commercial
meters can give different measurements for the same load and supply conditions, potentially leading
to unfair PF charges.

This work evaluates existing PF definitions and their measurement methods, considering the
fairness perspective for billing purposes under unbalanced nonsinusoidal voltage conditions. Here,
the fairness notion is in the sense that the meter (built based on a particular definition and measurement method) under a nonideal supply should lead to very close values as if it was submitted to
ideal balanced sinusoidal voltages. In other words, a fair PF definition should depend exclusively
on the load’s parameters, not supply quality. The fairness investigation considered computational
simulations with the application of 35280 different voltage conditions at the point of connection
of a constant impedance load and a three-phase induction motor (TIM) represented by their respective electrical models. In the sequel, the simulations’ findings were experimentally examined
in 3978 voltage conditions employing a controlled voltage source, a three-phase induction motor,
a mechanical load (DC generator and a variable resistor), a computer, and a speed sensor.

The results show that a PF definition that leads to a fair billing for a constant impedance (the
main load investigated in the literature) may not provide a fair billing for a TIM when supplied
with poor quality voltages. Additionally, this work has determined the fairest PF definitions and
characterized the class of their corresponding measurement algorithms for metering the PF of a
balanced constant impedance and a TIM submitted to a wide range of unbalanced nonsinusoidal
voltages. Notably, despite being recommended by IEEE Standard 1459-2010, the effective power
factor was not an adequate definition for the investigated supply conditions applied to the TIM.

BANKING MEMBERS:
Externo à Instituição - IVAN NUNES SANTOS - UFU
Presidente - 1455289 - JOAO YOSHIYUKI ISHIHARA
Interno - 1640512 - KLEBER MELO E SILVA
Externo à Instituição - RODRIGO ANDRADE RAMOS