Operation of an Inductive Power Transfer System

A secondary unit arrangement of an inductive power transfer system includes a secondary unit having a secondary winding structure for receiving a magnetic or electromagnetic field generated by a primary unit, a detector device including plurality of detection elements for detecting an arrangement comprising the primary unit, a determination unit for determining at least one electrical property of the detector device with respect to different regions of an arrangement, thereby generating determination results consisting of a determination result for different regions of the arrangement, a comparison unit for comparing the determination results with existing information about the arrangement to be detected, wherein the existing information includes information about expected values for the different regions of the arrangement, thereby generating a comparison result, and a decision unit for deciding from the comparison result whether the determination results indicates that the detector device has detected the arrangement as expected.