Development Of Single-Phase-to-Ground Fault Line Selection Device In Neutral Un-effectual Grounded Systems

Neutral non-grounded, High grounded and Petersen-coil grounded systems are also called neutral un-effectual grounded system (NUGS), and they are widely used in power distribution network in China. The fault rate of single-phase-to-ground of NUGS is high, but its fault line selection and location has not been well solved yet. It mostly because the fault current is small and the fault trait is not obvious. Has the single-phase earth fault when the undercurrent earth system, the accurate definite faulty line, to accelerates the line fault the elimination, enhances the movement reliability, reduces, because cuts power the mixed economy which creates to lose, has the very vital role.This article first to present domestic and foreign did about the undercurrent earth system single-phase earth fault route selection's principle and the research present situation introduced that had pointed out this domain's research difficulty, and summarized the existing breakdown route selection method, has appraised its good and bad points; Based on this, This paper designed the scheme of the hardware and software of the line selection and location device for NUGS. This paper presented the hardware scheme based on modularized designing; and offered the principle for IC device selection, the plan for the system designing and its realization,and has carried on the electromagnetic compatibility design to the installment hardware part, sharpened the installment anti-jamming ability and the installation cost; This article presented the scheme of the software designing with the software engineering thought, analyzed the every function module and presented their designing method; analyzed the importance of the software anti-jamming and produced the methods for enhancing the software reliability; established the software debug platform and finished the module software writing.In the laboratory existing condition's foundation, this article has built a simulation high-resistance earth system. The installment route selection's laboratory simulation result indicated that this article designs the hard software system route selection accuracy achieves 100%, has the high project significance.