Banca de QUALIFICAÇÃO: IGOR FERREIRA DO PRADO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : IGOR FERREIRA DO PRADO
DATE: 06/12/2019
TIME: 10:00
LOCAL: Sala 4 da ECT
TITLE:

Wavelet-Based Time-domain Differential Protection of Transmission Lines

KEY WORDS:

Percent Differential Protection, Alpha-plane Differential Protection; Transmission Line Protection, wavelet transform

PAGES: 100
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Sistemas Elétricos de Potência
SPECIALTY: Transmissão da Energia Elétrica, Distribuição da Energia Elétrica
SUMMARY:

Currently, the electric power systems feature extensive configurations, extreme complexity, and difficult operation. When a fault in the electrical system is not properly isolated it can cause system instability. Transmission lines are the elements most susceptible to failure due to their extension and exposure to external factors, around 70% of power system failures occur on transmission lines. Nowadays differential protection applied to transmission lines has become viable being commonly used, presenting well-defined characteristics of selectivity and operating speed. There are two methods of differential protection used commercially for this purpose: Percentage Differential Method; Alpha-plane Differential Method. Both methods are based on phasor current estimation, as a consequence, they have delays and limitations of transient analysis. This work makes a comparative study between these two techniques, aiming to identify the limitation of each method. For this, several internal and external faults were simulated using the MATLAB / Simulink software, considering variations in the type, location, incidence angle and fault impedance, as well as the presence of CT saturation. According to analyzes, the alpha-plane differential method has a slight advantage in event detection, since the sequence units are not influenced by the fault impedance. However, both methods have limitations in detecting high impedance faults and in the presence of series transmission line compensation. Consequently, this work proposes to recreate the traditional methods of line differential protection using the real-time boundary stationary wavelet transform (TWDB), which does not require phasor estimation providing a fast response characterized as a time-domain protection. Preliminary results show that it is possible to increase the fault detection rate and speed in the range of simulated cases, as well as to add a possible alternative for reducing the dependence of the synchronization signal via GPS and solutions for a fault classifier and fault locator in the protected zone.

BANKING MEMBERS:
Presidente - 1807863 - FLAVIO BEZERRA COSTA
Interno - 1196444 - RICARDO LUCIO DE ARAUJO RIBEIRO
Externo à Instituição - JOSÉ CARLOS DE MELO VIEIRA JUNIOR - USP
Externo à Instituição - KLEBER MELO E SILVA - UnB