Ct And Vt Modules - GE B90 Instruction Manual

3 HARDWARE
An LED on the front of the control power module shows the status of the power supply:
LED INDICATION POWER SUPPLY
CONTINUOUS ON OK
ON / OFF CYCLING Failure
OFF Failure
Switchgear
ground bus
The optional Ethernet switch shown in the connection diagram above is not available for the B90 device.
NOTE
Information on the CT and VT modules for the B90 relay is shown below.
Verify that the connection made to the relay nominal current of 1 A or 5 A matches the sec-
ondary rating of the connected CTs. Unmatched CTs may result in equipment damage or
inadequate protection.
Each AC current input has an isolating transformer and an automatic shorting mechanism that shorts the input when the
module is withdrawn from the chassis. There are no internal ground connections on the current inputs. Current transform-
ers with 1 to 50000 A primaries and 1 A or 5 A secondaries may be used.
Each B90 voltage input is intended for monitoring a single-phase voltage. The may include phase voltages or neutral volt-
age from the open-delta VT.
All CT and VT modules are available with enhanced diagnostics. These modules can automatically detect CT/VT hardware
failure and take the relay out of service.
Substitute the tilde "~" symbol with the slot position of the module in the following figure.
NOTE
GE Multilin
AC or DC
Heavy copper conductor
or braided wire
B8b B8a B6a B6b B5b
–
FILTER SURGE
Figure 3–13: CONTROL POWER CONNECTION
B90 Low Impedance Bus Differential System
NOTE:
14 gauge stranded
wire with suitable
disconnect devices
is recommended.
+
+
LOW
HIGH
CONTROL
POWER
UR-series
protection system
3.2 WIRING
AC or DC
+
—
OPTIONAL
ETHERNET SWITCH
827759AA.CDR

3.2.4 CT AND VT MODULES

3-13
3