Method for calculating inverse DG penetration level on basis of particle swarm optimization

The invention relates to the field of electrical power systems, and discloses a method for calculating an inverse DG penetration level on the basis of particle swarm optimization in case of no changes on the relay protection setting value of the original power distribution network, for solving the influence on power grid protection after low-level multi-DG access. The method comprises the following specific steps of: establishing a DG equivalent calculation model with a low-voltage through capacity according to the control strategy of inverse DG at first; then establishing a calculation model for a fault current after the grid connection of the inverse DG; finally establishing an optimization model taking DG access level maximum as a target, and taking the three-section current setting value of each circuit as the penetration level of an inequality constraint condition, and evaluating DG access by virtue of particle swarm optimization.