Fault detection system for distributed generation converters

In this paper, a fault detector algorithm for detecting voltage disturbances is proposed and analyzed. This method is based on the voltage characteristics instead of the current amplitude that is the most common approach in power distribution electrical systems. The proposed system uses a dual quadrature signal generator for each voltage component in a stationary reference frame to extract the positive- and negative-sequence components of the voltage. Besides a frequency-locked loop is used to estimate the voltage frequency. All these information is compared with the nominal values by means of hysteresis comparators. As a result, a fast and reliable fault detector system is obtained. Results of simulations and experiments are presented to illustrate the feasibility and performance of the proposed schemes.