We propose a new channel assignment algorithm called DVINS (distance variance insertion) to reduce intermodulation products (IMPs) in the one-level SCPC satellite systems. In addition, we propose a DELINS-INSDEL with SDELINS algorithm, which is well suited for improving the intermodulation advantage (IMA) performance. In obtaining sub-optimal channel assignment schemes, DVINS requires very short CPU time by using the variance of distribution for the elements in the distance triangle set. Since the DVINS algorithm does not need to calculate the IMP's levels by direct counting, it takes a shorter CPU time than any other published algorithms. We show the basic concept of the DVINS algorithm, and compare the performance of the DVINS algorithm with other algorithms in terms of the IMA and CPU time. The result shows that the new algorithm exhibits similar performance as other practical algorithms in terms of the IMA, while achieving a remarkable reduction in CPU time. Therefore, it would be highly desirable to use the proposed algorithm to obtain suboptimal channel assignment schemes in one-level SCPC satellite systems with many carriers.>