Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

First referenceCompare with

87L

Protection functions

Line current differential protection

Compares current information from the terminals of a protected line using a communication-assisted differential scheme.

Drawing use: SLD / Schematic
Application: Metering & protection
Reference family: IEEE / ANSI / Manufacturer

A distinction that matters

Line differential requires its measurement and communication arrangement; it is not a local distance zone or directional permissive alone.

Full reference

Protection functions

Differential protection

Differential protection compares quantities associated with the boundaries of a protection zone according to the selected implementation. Equipment and application suffixes can distinguish transformer, busbar, line or other arrangements. The base number alone does not define the zone or measurements.

Drawing use: SLD / Schematic
Application: Metering & protection
Reference family: IEEE / ANSI

A distinction that matters

Transformer differential, busbar differential and other differential applications are not interchangeable merely because they share the base number 87.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.