Practical Implementation of Delayed Signal Cancellation Method for Phase-Sequence Separation

In this paper, the use of a method for online detection of positive- and negative-sequence components of three-phase quantities, named the delayed signal cancellation (DSC) method, is investigated. Problems that arise in practical implementation of the DSC method in computer-controlled systems are investigated. Expressions of the detection error due to nonideal discretization are derived and calculations are verified experimentally. Two methods for reducing the detection error are presented and verified. It is also shown that the given expressions and proposed methods for reducing the detection errors can also be applied to the case of grid frequency variations