Abstract: As a continuation of our previous research this paper puts the stress on numerical simulation of tigher overvoltage induced by nonsynchronous closing. Main result as follow: Because of ordinary differential equation which is the mathematical model of preceding closing phases has two large harmonic solutions, so it implys possibility transformed from little harmonic solution to large one. Lagging currents i₁(t-τ₁), i₂(t-τ₁) play an important role to help intensify the billows and Waves in this transformation process.

Key words: nonsynchronous closing, Lagging current, higher overvoltage, large harmonic solution