Um algoritmo de estimação de frequência aplicado à proteção anti-ilhamento de fontes de geração distribuída.

Abstract

A new frequency estimation algorithm applied to anti-islanding protection of distributed generation is proposed in this thesis. The new frequency estimation algorithm is based on the complex least square theory, which uses a variable step-size which provides advantages and robustness to the proposed method. The protection scheme for islanding detection consists of the implementation of under and overfrequency protection function and the under and overvoltage function. The under and overvoltage protection functions it will be used as blocking signal of the main protection function (frequency relay) to guarantee the correct operation of the protection scheme. The discrete wavelet redundant transform was implemented in the under and overvoltage relay function for operation with the frequency relay function. This new proposal will made the monitoring of the three-phase voltage sinal by Clarke transformation. The test and validating of the proposed method are performed by digital simulation with analytical signals and electric power system of 30 buses of IEEE, in this, three distributed generators were connected. Simulations are considered, varying tha power of the distributed generators for cases of islanding of distributed generation. The results provided the performance of the proposed method to frequency estimation and the use of this in the anti-islanding protection of distributed generation.