ANSI Standard Device Numbers and Common Acronyms

A complete set of vocabulary flashcards covering ANSI standard device numbers, suffixes, and substation acronyms based on GE Digital Energy documentation.

Suffix 1

Positive-Sequence

Suffix 2

Negative-Sequence

Suffix BF

Breaker Failure

Suffix DCB

Directional Comparison Blocking

Suffix DCUB

Directional Comparison Unblocking

Suffix POTT

Pott: Permissive Overreaching Transfer Trip

Suffix PUTT

Putt: Permissive Underreaching Transfer Trip

Suffix SOTF

Switch On To Fault

Suffix TDC

Time-Delay Closing Contact

Suffix TDDO

Time Delayed Relay Coil Drop-Out

Suffix THD

Total Harmonic Distortion

AFD

Arc Flash Detector

CLP

Cold Load Pickup

DDR

Dynamic Disturbance Recorder

DFR

Digital Fault Recorder

HIZ

High Impedance Fault Detector

HMI

Human Machine Interface

HST

Historian

MET

Substation Metering

PDC

Phasor Data Concentrator

PMU

Phasor Measurement Unit

PQM

Power Quality Monitor

RIO

Remote Input/Output Device

RTD

Resistance Temperature Detector

RTU

Remote Terminal Unit / Data Concentrator

SER

Sequence of Events Recorder

TCM

Trip Circuit Monitor

VTFF

Vt Fuse Fail

ANSI Device 1

Master Element

ANSI Device 2

Time Delay Starting or Closing Relay

ANSI Device 3

Checking or Interlocking Realy

ANSI Device 7

Rate of Change Relay

ANSI Device 11

Multifunction Device

ANSI Device 12

Overspeed Device/Protection

ANSI Device 14

Underspeed Device

ANSI Device 16

Communication Networking Device

ANSI Device 21

Distance Relay

ANSI Device 24

Volts-per-Hertz Relay / Overfluxing

ANSI Device 25

Synchronizing or Synchronism-Check Device

ANSI Device 27

Undervoltage Relay

ANSI Device 30

Annunciator Relay

ANSI Device 32

Directional Power Relay

ANSI Device 40

Field Relay / Loss of Excitation

ANSI Device 46

Reverse-Phase or Phase Balance Current Relay or Stator Current Unbalance

ANSI Device 47

Phase-Sequence or Phase Balance Voltage Relay

ANSI Device 48

Incomplete Sequence Relay / Blocked Rotor

ANSI Device 49

Machine or Transformer Thermal Relay / Thermal Overload

ANSI Device 50

Instantaneous Overcurrent Relay

ANSI Device 51

Ac Time Overcurrent Relay

ANSI Device 52

Ac Circuit Breaker

ANSI Device 55

Power Factor Relay

ANSI Device 59

Overvoltage Relay

ANSI Device 60

Voltage or Current Balance Relay

ANSI Device 62

Time-Delay Stopping or Opening Relay

ANSI Device 63

Pressure Switch Detector

ANSI Device 67

Ac Directional Overcurrent Relay

ANSI Device 68

Blocking Relay / Power Swing Blocking

ANSI Device 74

Alarm Relay

ANSI Device 79

Ac Reclosing Relay / Auto Reclose

ANSI Device 81

Frequency Relay

ANSI Device 86

Locking-Out Relay

ANSI Device 87

Differential Protective Relay

ANSI Device 50/74

Ct Supervision

ANSI Device 27TN/59N

$100\%$ Stator Earth Fault