Schweitzer Engineering Laboratories, Inc.
SEL- 2664S Data Sheet
9
The SEL-2664S is generally applied to single generators
with high-resistance grounded neutral as shown in
through
. Similarly, it can also be
applied to a parallel generators configuration if only one
of the generators is grounded (e.g., cross-compound
generators).
For two generators connected in parallel, each with high-
resistance grounded neutral but sharing a common step-
up transformer, you can use two SEL-2664S Relays
(see
), and follow the special considerations and
limitations described in the
SEL-2664S Instruction
Manual
for such a configuration.
Figure 13
Parallel Generators Configuration—AC Connections Using Two SEL-2664S Relays
for a typical example of the dc connections
for 100 percent stator ground protection using the
SEL-2664S Stator Ground Protection Relay (stator-to-
ground insulation resistance measurement) and the
SEL-2664 Field Ground Module (dc field-to-ground
insulation resistance measurement).
Figure 14
Typical DC Connections for an SEL-2664S
Application
NGR2
NGT2
CTN2A
VN
NN
X2
Generator 2
Generator 1
X1
CTN2B
CTN1B
of
SEL-2664S-2
To
CO1
To
CO2
of
SEL-2664S-2
To
CO1
To
CO2
Generator Relay
(if used)
VN
NN
NGR1
CTN1A
X1 X2
NGT1
IN
D02/VN
D01/NN
C02
C01
SEL-2664S-1
2-C twisted pair (preferably shielded)
Do not ground the CTN leads.
I_SRC
IN
D02/VN
D01/NN
C02
C01
SEL-2664S-2
To
CTN1B
& CTN2B
I_SRC
52G1
52G2
WYE
GSU XFMR
DELTA
Generator Relay
(if used)
A11
A10 IN01
AO1
AO2
AO3
Alarm
Self Test/Status
SEL
-2
664S
43AMP
ON
Fiber-Optic Cable
With ST Connectors
From SEL-2664
RX
TX
Port 2
A04
A05
Trip 86G
or
Ground Fault Alarm
+/H
BO1
BO2
–/N
-DC
+DC
OUT02
GND
OUT01
