Based on the theory of bifurcation and chaos,we studied the effects of three dynamic parameters (load active power P₁,reactive power Q₁ and generator mechanical power P_m) on the voltage stability of a power system with Walve integrated load.In different load condition,the system status characteristics changing with bifurcation parameters has been studied by using Lyapunov exponential spectrums,equilibrium solution manifold curves and phase trajectory simulations.The study showed that when Q₁ increased from 0 with light P₁ or P₁ increased from 0 with heavy Q₁,Hopf and saddle-node bifurcations were dynamical natures of voltage unstable and collapse.And with the increase of the bifurcation parameter,voltage level significantly decreased.When P₁ was light and Q₁ was heavy,the voltage level indistinctively decreased with changing of P_m.And before reaching the nose point (the saddle node bifurcation point),the system became chaotic due to the period doubling bifurcation.And then the voltage collapsed after small perturbation of P_m since the tension and folding transformations of the chaotic orbit were not balanced.The result also indicated that when the system was run under condition of light P₁ or Q₁,the voltage stable operating range and the power transfer limitation could be increased by adjusting the generator mechanical power.But when P₁ was light and Q₁ was heavy,the adjustable range would be affected by period doubling bifurcation.