The nonlinear equation of the electric power system can be deduced from an analysis of the experimental results of a research conducted on a certain varactor diode circuit system. The perturbation solution of the equations can be worked out by using the direct perturbation method. According to Melnikov chaos criteria, the perturbation solution thus obtained proves to be a chaotic solution, which shows the chaotic characteristics of the nonlinear circuit system. Theoretical analysis results show that an effective control over the chaotic behaviors in the system can be realized by adjusting the system parameters or initial boundary conditions. The corresponding numerical simulation results show that the proposed method is effective and feasible, thus verifying the results of the theoretical analysis.