Specific Types Flashcards
1
Q
21G
A
Ground distance
2
Q
21P
A
Phase distance
3
Q
27P
A
Phase undervoltage
4
Q
27S
A
DC undervoltage relay
5
Q
27TN
A
Third harmonic neutral undervoltage
6
Q
27TN/59N
A
100% stator earth fault
7
Q
27X
A
auxiliary undervoltage
8
Q
27 AUX
A
undervoltage auxiliary input
9
Q
27/27X
A
Bus / Line undervoltage
10
Q
27/50
A
Accidental generator energization
11
Q
32L
A
Low forward power
12
Q
32H
A
High directional power
13
Q
32N
A
Wattmetric zero-sequence directional
14
Q
32P
A
Directional power
15
Q
32R
A
Reverse power
16
Q
37P
A
Underpower
17
Q
49RTD
A
RTD biased thermal overload
18
Q
50BF
A
Breaker failure
19
Q
50DD
A
Current disturbance detector
20
Q
50EF
A
End fault protection
21
Q
50G
A
Ground instantaneous overcurrent
22
Q
50IG
A
Isolated ground instantaneous overcurrent
23
Q
50LR
A
Acceleration time
24
Q
50N
A
Neutral instantaneous overcurrent
25
50NBF
Neutral instantaneous breaker failure
26
50P
Phase instantaneous overcurrent
27
50SG
Sensitive ground instantaneous overcurrent
28
50SP
Split phase instantaneous overcurrent
29
50Q
Negative sequence instantaneous overcurrent
30
50/27
Accidental energization
31
50/51
Instantaneous / time-delay overcurrent relay
32
50/74
CT trouble
33
50/87
Instantaneous differential
34
51G
Ground time overcurrent
35
51LR
AC inverse time overcurrent (locked rotor) protection relay
36
51N
Neutral time overcurrent
37
51P
Phase time overcurrent
38
51R
Locked / stalled rotor
39
51V
Voltage restrained time overcurrent
40
51Q
Negative sequence time overcurrent
41
52a
AC circuit breaker position (contact open when circuit breaker open)
42
52b
AC circuit breaker position (contact closed when circuit breaker open)
43
59B
Bank phase overvoltage
44
59P
Phase overvoltage
45
59N
Neutral overvoltage
46
59NU
Neutral voltage unbalance
47
59P
Phase overvoltage
48
59X
Auxiliary overvoltage
49
59Q
Negative sequence overvoltage
50
60N
Neutral current unbalance
51
60P
Phase current unbalance
52
64F
Field ground protection
53
64R
Rotor earth fault
54
64REF
Restricted earth fault differential
55
64S
Stator earth fault or sub-harmonic stator ground protection
56
64TN
100% stator ground
57
67G
Ground directional overcurrent
58
67N
Neutral directional overcurrent
59
67Ns
Earth fault directional
60
67P
Phase directional overcurrent
61
67SG
Sensitive ground directional overcurrent
62
67Q
Negative sequence directional overcurrent
63
78V
Loss of mains
64
81O
Over frequency
65
81R
Rate-of-change frequency
66
81U
Under frequency
67
87B
Bus differential
68
87G
Generator differential
69
87GT
Generator / transformer differential
70
87L
Segregated line current differential
71
87LG
Ground line current differential
72
87M
Motor differential
73
87O
Overall differential
74
87PC
Phase comparison
75
87RGF
Restricted ground fault
76
87S
Stator differential or percent differential
77
87T
Transformer differential
78
87V
Voltage differential
