Selection guide for all
applications
1
Standard transformer application diagrams
do not take voltage levels into account:
b the transformer primary winding is always
at the top
b the transformer secondary winding is
always at the bottom.
The transformer primary and secondary
windings need to be protected.
The Sepam proposed can be installed on
either the primary or secondary winding of
the transformer.
The other winding can be protected by
an incomer or feeder type substation
application Sepam.
Transformerapplications
Protectionfunctions ANSI
code
Phase overcurrent (1)
Earth fault /
Sensitive earth fault (1)
Breaker failure
Negative sequence /
unbalance
Thermal overload for
machines (1)
Restricted earth fault
differential
Two-winding transformer
differential
Directional phase
overcurrent (1)
Directional earth fault (1)
Directional active
overpower
Overfluxing (V / Hz)
Positive sequence
undervoltage
Remanent undervoltage
Undervoltage (L-L or L-N)
Overvoltage (L-L or L-N)
Neutral voltage
displacement
Negative sequence
overvoltage
Overfrequency
Underfrequency
Thermostat / Buchholz (2)
Temperature monitoring
(16 RTDs) (3)
T20
T23
T40
T42
T81
T82
T87
50/51
50N/51N
50G/51G
0BF
49RMS
REF
T
67N/67NC
P
27D
R
9
9N
v
v
RTDs
v
v
RTDs
v
v
v
RTDs
v
v
v
RTDs
v
H
L
26/63
38/49T
v
v
v
v
v
v
RTDs RTDs RTDs
Synchro-check (4)
The figures indicate the number of units available for each protection function
b standard, v options.
(1) Protection functions with 2 groups of settings.
(2) According to parameter setting and optional input/output modules.
(3) With optional MET148-2 temperature input modules.
(4) With optional MCS025 synchro-check module.
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18/04/2007 10:59:35