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Wednesday, 18 April 2012

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

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