Electrical distance (ED) is the primary basis for dividing voltage control areas in power grids. Both classic methods and their improved versions for calculating electrical distance rely on the power flow Jacobian matrix, which may lead to frequent adjustments in partitioning schemes and increase the difficulty of reactive power and voltage management as the randomness of power sources and loads continues to grow. Therefore, this paper first reviews the classic definition of electrical distance and then demonstrates that the ratio of voltage changes at a pair of nodes in a power system after a small disturbance can be approximately obtained using network topology parameters. Next, following the classic formula for calculating electrical distance, a new method for computing electrical distance based on network topology is presented. Finally, this method is applied to the NE-39 and NE-68 node systems, and the results are compared with those obtained using the classic method in terms of electrical distance and partitioning schemes, validating the effectiveness of the proposed approach.