On February 4， 2011， a blackout occurred in Northeast of Brazil. The process of blackout is introduced and analyzed. An error of an electronic component in the relay equipment aroused the false action of the breaker failure protection in the substation Luiz Gonzaga and resulted in the blackout finally. With reference to the blackout incident in Brazil， the deficiency of the breaker failure logic adopted in Brazil power grid is analyzed， and the standard breaker failure logic developed by State Grid Corporation of China is also analyzed. The analysis results reveal that the standard logic can avoid the occurring of similar incidents.