Bus - GE B90 Instruction Manual

CHAPTER 5: SETTINGS

5.4.4 Bus

SETTINGS  SYSTEM SETUP  BUS  BUS ZONE 1(6)  BUS ZONE 1(6) INPUT A(X)
 BUS ZONE 1 INPUT A

The number of available zones and their size (maximum number of inputs) are optional and controlled by the
software option portion of the order code. See the Order Codes section in chapter 2 for information on the
maximum number of zones and inputs for a given B90 model.
Six bus differential zones are available. Each zone is associated with its own bus differential protection and CT trouble
monitoring elements. A differential zone is defined by up to 24 pairs (inputs A to X) of current input–bus connection status
values.
— This setting defines a current input to the zone. Selections include all the CT channels available in the relay as
BUS 1A CT
per configured hardware. The protected bus zone is uniquely identified as the portion of the bus between the selected
current sources (CTs).
— This setting configures the CT orientation with respect to the protected zone. Bus differential and CT
BUS 1A DIRECTION
trouble decisions are based on current summation and thus correct orientation selection is important. The following figure
shows a tie-breaker dividing a single bus into two sections, defined as zone 1 and zone 2. The tie-breaker CT (F5) is
common to both zones and therefore the respective direction settings are opposite. The CT polarity dots are in relation to
the protected zone and are terminated to the "common" of the tapped (1 A / 5 A) inputs. The polarity dots for the zone 2 CTs
face outward with respect to the bus; as such, the F5 to F8 direction settings are "IN". Similarly, the F1 to F4 CTs for zone 1
are selected as "IN." However, the polarity dot orientation for the F5 CT faces inward with respect to zone 1 and therefore
the setting is "OUT."
BUS 1E DIRECTION
B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
Figure 5-72: Recloser curves GE119, GE135, and GE202
BUS 1A CT:

F1
BUS 1A DIRECTION:

IN
BUS 1A STATUS:

Off
Range: available CT channels
Range: IN, OUT
Range: FlexLogic operand
SYSTEM SETUP
5
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