A three-dimensional dynamic-electrification coupled model is used to investigate noninductive electrification before the first discharge in a single cell of thunderstorm. Two laboratory-based parameterizations of noninductive graupel-ice charge separation, S91 and SP98, are compared. The evolution characteristics of noninductive charge separation regions, polarity, magnitude, structure and their relationships with effective liquid water content, environment temperature, hydrometeor distribution, and convection are analyzed in this paper. The model results suggest that, in S91 scheme, charge separation initially occurs in the region with high values of temperature and effective liquid water content, and then moves to the region with low values. The charge separation rate quickly increases. Its domain polarity changes from positive to negative. The charge structure switchs from positive dipole to tripole. In SP98 scheme, graupel easily carries positive charges, owing to its large range of big rime accretion rate. It is likely to produce an inverted-polarity charge structure, but going with time, it tends to present tripole. There are some common characteristics between the two schemes before the first discharge. Firstly, the charge region altitudes are high and nearly located in the upper part of updraft and the outflow region in the front of storm moving direction. Secondly, positive charge separation primarily occurs in the region with high values of effective water content (or rime accretion rate) and temperature, however, negative in the region with low values. Thirdly, the positive and negative charging centers are almost consistent during the evolution, respectively. The positive corresponds with the graupel number concentration center, while the negative easily occurs in the coexisting region center of ice and graupel.