IEC 62271-215:2021 is applicable to phase comparators designed to be plugged into the testing points of a voltage detecting and indicating system (VDIS) according to IEC 62271-213, to give an indication of the result of a phase comparison.The main usage is to provide a clear evidence of the phase relationship between two energized parts of a high-voltage network, at the same nominal voltage and frequency before coupling them.This first edition cancels and replaces the first edition of IEC 61243-5 published in 1997 and the first edition of IEC 62271-206 published in 2011. This edition constitutes a merging of the content of IEC 61243-5 and IEC 62271-206.This edition includes the following significant technical changes with respect to the previous editions of IEC 61243-5 and IEC 62271-206:

1. the document does not include the specific phase comparators (SPCs) as defined in IEC 61243-5, which was specific to manufacturers, and takes back the technical principles of the universal phase comparator (UPC) for VDIS of all manufacturers;
2. the phase comparator for sequential connected operation is introduced to facilitate the operation of phase comparation of large MV panels.