Understand the difference.

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

SOE

Symbols

Sequence-of-events recorder

A sequence-of-events recorder monitors breaker auxiliary contacts, protection trip outputs, alarms and other binary signals, and stores each change with an accurate timestamp. After an incident the list shows which device operated first, which is often impossible to tell from alarms alone.

Drawing use

Schematic

Application

Metering & protection

Reference family

Manufacturer

A distinction that matters

An SOE recorder logs binary changes in time order; a disturbance recorder captures analogue waveforms.

Full referenceAdd to legend

DFR

Symbols

Disturbance recorder

A disturbance recorder captures sampled current and voltage waveforms together with breaker and protection contact states when a trigger occurs. Pre-fault and post-fault data let engineers check how protection performed, so the recorder is drawn with its analogue inputs from CTs and VTs and its binary inputs from trip and position contacts.

Drawing use

SLD / Schematic

Application

Metering & protection

Reference family

IEC / IEEE / ANSI / Manufacturer

A distinction that matters

A disturbance recorder stores high-rate waveforms around an event; a sequence-of-events recorder stores timestamped contact changes only.

Full referenceAdd to legend

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