Method and apparatus for detecting islanding conditions of a distributed grid

摘要

An exemplary method and apparatus for detecting islanding conditions of a distributed grid are disclosed, wherein transfer of power through a power electrical unit is controlled on the basis of a control reference. The apparatus includes a first stage and a second stage performing a respective portion of the method. The first stage injects a reactive component to the control reference, and, for at least one electrical quantity of the grid, determines a change in the quantity induced by the injected component, and determines, on the basis of the change in the electrical quantity, whether to move to the second stage of the method. The second stage, for at least one electrical quantity of the grid, determines a value of the electrical quantity, forms a positive feedback term using at the determined value adding a positive feedback term to the control reference, determines a change in an electrical quantity induced by the feedback term, and determines islanding condition on the basis of the change in the quantity induced by the feedback term.

主权项

1. A method for detecting islanding conditions of a distributed grid, wherein transfer of power through a power electrical unit in the distributed grid is controlled on the basis of a control reference, the method comprising:
a first stage and a second stage, wherein the first stage comprises:
injecting a reactive component to the control reference; andfor at least one electrical quantity of the grid:
determining a change in the quantity induced by the injected component, anddetermining, on the basis of the change in the electrical quantity,whether to move to the second stage of the method, and wherein the second stage comprises, for at least one electrical quantity of the grid:
determining a value of the at least one electrical quantity;forming a positive feedback term using the determined value;adding the positive feedback term to the control reference;determining a change in an electrical quantity induced by the feedback term; anddetermining an islanding condition on the basis of the change in the quantity induced by the positive feedback term.