Research And Realization On Selective Leakage Protector Based On Transient Analysis Method

The non-effective neutral grounded system is popular in power distribution networks. This grounding method is helpful to improve the power supply reliability. But it is difficult to determine the fault branch and realize the fault line detection when the single-phase to ground faults occurs. The reason is that the single-phase to ground fault does not constitute a short-circuit loop, the faulty component is too small and it is rather difficult to identify the faulty branch under the disturbance and the detecting error.This paper deals with this problem, analyzes the zero sequence current and the zero sequence voltage characteristics in small current neutral grounding system, analyzes the present situation of fault line detection and the advantage and deficiency of a variety of location algorithms have been put forward. Transient analysis is adopted as the location algorithm basis, and after in-depth study on wavelet theory, the wavelet transform of analyzing the fault is proposed by using the characteristics of small current fault, and realize the fault line detection. In the hardware design it uses TMS320C2812 as the controller chip, and synchronous sampling chip MAX1308 to ensure the data collecting synchronization. This protection has been completed, and experiments show that this scheme can improve the reliability and sensitivity of the selective leakage protection.