GE B30 UR Series Instruction Manual page 272

5.6 GROUPED ELEMENTS
In this scheme, the normal voltage level halts the differential element. An actual bus fault operates the undervoltage ele-
ment, thereby permitting the differential element to operate. This can be applied for bus configurations of up to five feeders
with the voltage signal available. If applied, use the undervoltage function to supervise the main differential output with an
AND gate in the FlexLogic equation before driving the output contact.
Using the drop-out undervoltage operand as the Block input to the differential element is not recommended. The differential
element includes the saturation detector that responds to certain time relationships between the differential and restraining
currents, and therefore, it must be operational all the time in order to function properly.
This element may be used to give a desired time-delay operating characteristic versus the applied fundamental voltage
(phase-to-ground or phase-to-phase for wye VT connection, or phase-to-phase for delta VT connection) or as a definite
time element. The element resets instantaneously if the applied voltage exceeds the dropout voltage. The delay setting
selects the minimum operating time of the phase undervoltage. The minimum voltage setting selects the operating voltage
below which the element is blocked (a setting of "0" will allow a dead source to be considered a fault condition).
SETTING
PHASE UV1
FUNCTION:
Disabled = 0
Enabled = 1
SETTING
AND
PHASE UV1
BLOCK:
Off = 0
SETTING
}
PHASE UV1 SOURCE:
Source VT = Delta
VAB
5
VBC
VCA
Source VT = Wye
SETTING
PHASE UV1 MODE:
Phase to Ground Phase to Phase
VAG VAB
VBG VBC
VCG VCA
5-150
AND
SETTING
AND
PHASE UV1
MINIMUM VOLTAGE:
<
VAG or VAB Minimum
VBG or VBC < Minimum
AND
<
VCG or VCA Minimum
Figure 5–63: PHASE UNDERVOLTAGE1 SCHEME LOGIC
B30 Bus Differential System
SETTING
PHASE UV1
PICKUP:
PHASE UV1
CURVE:
PHASE UV1
DELAY:
<
RUN VAG or VAB PICKUP
t
V
<
RUN VBG or VBC PICKUP
t
V
<
RUN VCG or VCA PICKUP
t
V
5 SETTINGS
FLEXLOGIC OPERANDS
PHASE UV1 A PKP
PHASE UV1 A DPO
PHASE UV1 A OP
PHASE UV1 B PKP
PHASE UV1 B DPO
PHASE UV1 B OP
PHASE UV1 C PKP
PHASE UV1 C DPO
PHASE UV1 C OP
FLEXLOGIC OPERAND
OR PHASE UV1 PKP
FLEXLOGIC OPERAND
OR PHASE UV1 OP
FLEXLOGIC OPERAND
AND PHASE UV1 DPO
827039AB.CDR
GE Multilin