The invention discloses an AC / DC power
system load flow calculation method and
system based on a quasi-Newton method, and the method comprises the steps: building load flow calculation models of a conventional
DC converter station and a flexible
DC converter station based on the input and output characteristics of an AC side and a DC side; a rectangular coordinate equation which only considers node
voltage in traditional load flow calculation is expanded to an augmented rectangular coordinate
system which considers node
voltage and current, and a unified load flow calculation model of AC-DC load flow calculation is established; determining the direction and step length of the first iteration through a Newton method, and obtaining an iteration initial value of the quasi-Newton method; the quasi-Newton iteration matrix is continuously updated in the
iteration process, so that repeated derivation calculation of the Jacobian matrix and inversion are not needed; and when the
power flow solution is iterated to meet the requirement, outputting a
power flow calculation solution. Through the calculation method provided by the invention, the unified iteration of the
alternating current and
direct current power flow can be realized by utilizing the
alternating current and
direct current unified power flow model, meanwhile, the time required by each iteration is saved by adopting the quasi-Newton method, and the method has the characteristic of super-linear convergence.