The Research On A New Method Of Fault Line Selection And Its Implementation

Neutral non-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 single phase-to-ground fault happens most frequently in distribution network. Due to the small fault current and unobvious fault features after single phase-to-ground fault, the problem of fault line selection has been studied for years, however it is still not solved perfectly, which has seriously blocked the development of reliability of power supply and automation level of distributionnetwork.Firstly, stable and transient features of single phase-to-ground fault in NUGS aredeeply analyzed and lots of dynamic simulation experiments have been made. This article analyze the fault of small current neutral grounding system , and presents "Residual Current Method" which based on Fourier algorithm to calculate steady-zero current, Using improved "Residual Current Method" for the single phase-to-ground fault basic route selection method, This new method has no effect of transient of power system or harmonic contamination or dissymmetry structure of circuitry, by which the single-phase to ground fault can be detected; By application information fusion principle, Proposed based on the "Residual Current Method" class the fuzzy comprehensive route selection method which unified with the transition condition first half-wave phase, Structure fuzzy comprehensive route selection criterion;A solution based on the 80C196 Single-Chip according to the requisition of "Residual Current Method" in the single-phase to ground faulty is presented, In detail elaborated the installment realization principle, the composition structure and its the software and the hardware realization method, And moved the mold laboratory in the Hunan University electrical power system to carry on the dynamic analogous system single-phase earth fault route selection experiment to examine.Massively electrical power system dynamic modeling experiment result to indicate that, this article proposes the fuzzy synthesis route selection method which unifies with the transition condition first half-wave phase applies based on the "Residual Current Method" class in the neutral point earth system and can correctly differentiate the generatrix and the line fault after the quenching of arc coil earth system, accurately selects the faulty line; The fault line selection installment movement correct, the sensitivity and the reliability high, the movement are stable, antijamming ability. Thus indicated this...