ABB RET 543 - Page 62

Transformer Terminal RET 541, RET 543, RET 545
1MRS755543
62
Earth-fault 87TN Io> Stabilized restricted
earth-fault protection
REF4A
87TN Io> Stabilized restricted
earth-fault protection
REF4B
Overload 49M/49G/49T 3
Three-phase thermal
protection for devices
(motors, generators and
transformers)
TOL3Dev
Negative phase-
seguence
46 I
2
> Negative phase-
seguence protection,
low-set stage
NPS3Low
46 I
2
>> Negative phase-
seguence protection,
high-set stage
NPS3High
Overvoltage/
undervoltage
59 3U> Three-phase
overvoltage, low-set
stage
OV3Low
59 3U>> Three-phase
overvoltage, high-set
stage
OV3High
27 3U< Three-phase
undervoltage, low-set
stage
UV3Low
27 3U<< Three-phase
undervoltage, high-set
stage
UV3High
27, 47, 59 U
1
<
U
2
>
U
1
>
Phase-sequence voltage
protection, stage 1
PSV3St1
27, 47, 59 U
1
<
U
2
>
U
1
>
Phase-sequence voltage
protection, stage 2
PSV3St2
Overfrequency/
underfrequency
81U/81O f</f>, df/dt Underfrequency or
overfrequency, stage 1
(incl. rate of change)
Freq1St1
81U/81O f</f>, df/dt Underfrequency or
overfrequency, stage 2
(incl. rate of change)
Freq1St2
81U/81O f</f>, df/dt Underfrequency or
overfrequency, stage 3
(incl. rate of change)
Freq1St3
81U/81O f</f>, df/dt Underfrequency or
overfrequency, stage 4
(incl. rate of change)
Freq1St4
81U/81O f</f>, df/dt Underfrequency or
overfrequency, stage 5
(incl. rate of change)
Freq1St5
Overexcitation 24 U/f> Overexcitation protection,
low-set stage
OE1Low
24 U/f>> Overexcitation protection,
high-set stage
OE1High
Additional func-
tions
68 3I
2f
> Three-phase transformer
inrush and motor start-up
current detector
Inrush3
60 FUSEF Fuse failure supervision FuseFail
Table 30: Protection functions
Types of fault IEEE Device No. IEC Symbol Protection function Function block
code