The Design and Implement of Intelligent Trip Device for LV Circuit Breaker

Compared with normal trip devices, much more functions were realized in intelligent trip device we designed, such as electric parameters measure, circuit protect, breaker status online-detect, communicate with mainframe of switch automatic system and so on. In this paper, electric signal collection, amplification, isolation were investigated, harmonic analysis was carried out, spectrum leakage was solved in fast Fourier transform by using window function and interpolation in frequency domain, corresponding calculation of non-sine wave current, voltage, power factor were presented, and trip algorithm was designed elaborately. As a result, a set of intelligent trip device can realize different trip characteristics flexibly and be widely applied in many situations by setting different parameters. Disturbance from strong electromagnetism was considered during the process of hardware design. So it has higher reliability and wider applications compared with normal ones. The results show that all requirements in test have been implemented wholly.