Optimal trend;  Nonlinear homotopy internal point method;  Homotopy variables

Taking the power consumption of the generator as the objective function, the upper and lower limits of the generator power output and the upper and lower limits of the node voltage as the variable inequality constraint, and the nodal power flow equation as the equation constraint to form the mathematical model of the optimal power flow, the nonlinear homotopy internal point method is used to solve the optimal power flow problem. The calculation of IEEE6 and IEEE118 node test systems shows that the calculation results are very close to the results obtained by using the internal point method, and the unfeasible conditions can be detected in time.