Voltage Elements - GE B90 Instruction Manual

GROUPED ELEMENTS
For example, in the four-IED application example shown earlier, IED 2 is two "bridges" away from IED 4; therefore, the Total
BF Reset Time is 0.7 + 2 x 0.2 = 1.1 of a power system cycle.
Note that a message delivery time of 0.2 of a cycle per "bridge" applies when the
The relay uses sophisticated algorithms to speed up the reset time of the breaker failure overcurrent supervision.
Caution must be paid when testing the B90 for BF reset times. In particular, the current must be interrupted in a
way resembling the actual breaker operation (zero-crossing).

5.6.5 Voltage elements

5.6.5.1 Menu
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  VOLTAGE ELEMENTS
 VOLTAGE ELEMENTS

5.6.5.2 Undervoltage (ANSI 27)
5
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  VOLTAGE ELEMENTS  UNDERVOLTAGE 1(12)
 UNDERVOLTAGE 1

The undervoltage element supervises (low-voltage check) current based main protection (that is, differential, breaker
failure, end fault, and time overcurrent backup protection). The B90 accepts phase-to-ground or phase-to-phase voltage
input configurations. If the intention is to operate all three phases for any one phase voltage collapse, appropriate
FlexLogic operand exchanges must occur between the B90s using fiber optic communications (direct inputs and outputs).
The undervoltage element also accepts the neutral voltage (3V0) from an open-corner delta VT arrangement. In this case,
the FlexLogic output is inverted to accomplish the 3V0 overvoltage functionality.
5-168
Total BF Reset Time = 0.7 of a power cycle + 0.2 of a power cycle x Direct I/O bridge count
= 0.7 + 2 x 0.2 = 1.1 of a power cycle
 UNDERVOLTAGE 1


 UNDERVOLTAGE 12


UNDERVOLTAGE 1

FUNCTION: Disabled
UNDERVOLTAGE 1

VT: F5
UNDERVOLTAGE 1

PICKUP: 0.800 pu
UNDERVOLTAGE 1 MIN

VOLTAGE: 0.000 pu
UNDERVOLTAGE 1 PKP

DELAY: 0.000 s
UNDERVOLTAGE 1 RST

DELAY: 0.000 s
UNDERVOLTAGE 1 BLK:

Off
UNDERVOLTAGE 1

TARGET: Self-Reset
UNDERVOLTAGE 1

EVENTS: Disabled
DIRECT I/O DATA RATE
See below

Range: Disabled, Enabled
Range: Available voltage channels
Range: 0.004 to 3.000 pu in steps of 0.001
Range: 0.000 to 1.000 pu in steps of 0.001
Range: 0.000 to 65.535 s in steps of 0.001
Range: 0.000 to 65.535 s in steps of 0.001
Range: FlexLogic operand
Range: Self-Reset, Latched, Disabled
Range: Enabled, Disabled
B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
Eq. 5-4
is set to 128 kbps.