The power anti-regulation phenomenon is very common in the hydropower generator during the power adjust process
because of the water hammer effect of water system and the nonlinear characteristics of the hydro generator. The simulation and theoretical analysis shows that the main factors that cause the power anti-regulation are the Tw of hydropower generator
the time to close the gate and the comprehensive adjustment coefficient e. It analyzes the power anti-regulation of NO. 3 unit of a hydropower station. And it makes a series of parameter sensitivity analysis experiments. It optimizes the governor guide vane closing rate ultimately. The result shows that the power anti-regulation is greatly reduced and the regulation quality is improved greatly.