Relay numbering

Relay no	Description
2	Time delay starting or closing
3	Checking/interlocking
4	Master contactor
21	Distance relay
25	Synchronizing relay
27	Under voltage relay
30	Enunciators relay
32	Directional power
37	Under current/ under power
40	Field failure
46	Phase balance current
49	Machine/transformer thermal
50	Instantaneous over current or rate of rise
51	AC time over current
52	AC circuit breaker
52a	Circuit breaker auxiliary contact NO
52b	Circuit breaker auxiliary contact NC
55	Power factor relay
56	Field application relay
59	Over voltage
60	Voltage or current balance
64	Earth fault
67	AC directional over current
68	Blocking relay
74	Alarm
76	DC over current
78	Phase angle measuring or out of step
79	AC re-closing
81	Frequency relay
83	Automatic selective control
85	Carrier or pilot wire receiver
86	Locking out or master trip
87	Differential protection
94	Anti pumping
95	Supervision
96	Bus differential
63	Buchholz relay
49	Transformer winding /oil temperature
	SHORT TAXT
CAG14	High impedance differential relay with variable current setting
CDAG	Over current relay with time delayed phase fault elements having any of the standard inverse characteristic plus an instantaneous earth fault element
CDG11	Inverse time over current relay with basic inverse time characteristic and a single contact on the disc
CDV22	Voltage controlled inverse time overcurrentrelay
CTN	Negative phase sequence with inverse time characteristics for generator protection static
CTS	Motor stalling relay
DBAE4	Rotor earth fault
DTH	Static transformer percentage biased differential with harmonic restraint
FMG11	Over frequency relay
FMG12	Under frequency
GTT	Over fluxing
HORM4	Tran slay plain feeder medium speed pilot wire
TTT	Transformer oil/winding temp indicator with alarm and trip functions
VAG11	AC under voltage or over voltage with fixed setting
VAG21	AC under voltage or over voltage with fixed setting with drop off pick up ratio
VAJH13	Low burden high speed tripping relay with hand reset contact
VAJ513	Low burden high speed tripping relay with self reset contact
VATX11	High speed tripping relay with electrical or hand and electrical reset contact
VAT	Independent (definite) time delay relay
VAX12	DC supply failure relay
VAX21	Trip circuit supervision relay when the circuit breaker is closed
VAX31	Trip circuit supervision relay when the circuit breaker is either open or closed.
VDH12	Inverse time natural displacement relay for use in distribution system
VTT	Static definite time delay relay
YEGF	Generator asynchronous running detection relay