The Design Of An Intelligence Switch Based On Ameliorated Fourier Transform Algorithm

Traditional protect of short circuit is that the switch is directly switched off when power system has happened short circuit. Because of the long time of drawn-arc during cutting high-value current, the equipment's capability of breaker has to very large. The paper gives a new idea that rapidly cut off the circuit at low-current time when power system has happened short circuit. And we design an intelligence switch that is to be used to protect power system. The switch's strong advantage is that cutting-current is small, so time is very short when power system, which happened short circuit is switched off. The key of this method is that get the time when current value equal zero beforehand, and try to make the circuit break at that time. The paper researches the failure power system, and focuses the three-phase symmetry short circuit because it is the most severity.The paper gives a method to get the time when current value equal zero beforehand, based on researching the three-phase symmetry short circuit adopting half-wave Fourier Transform Algorithm. And the method is simulated with MATLAB. The paper designs a hardware system and software system to implement the cutting-low-switch. The hardware adopts DSP, and The software adopts C and assemble language.