Open Pole Detector - GE D90 Plus Instruction Manual

CONTROL ELEMENTS

Open pole detector

320
Figure 271: VT fuse failure scheme logic
The open pole detector is intended to identify an open pole of the line circuit breaker. The
scheme monitors the breakers auxiliary contacts, current in the circuit, and voltage
(optional) on the line. The scheme generates output operands used to block the phase
selector and some specific protection elements, thus preventing maloperation during the
dead time of a single pole autoreclose cycle or any other open pole conditions.
The scheme declares an open pole at the moment a single-pole trip is issued.
In two breaker and breaker-and-a-half applications, an open pole condition is declared
when any of the following occur.
• Both breakers have an open pole on the same phase.
• The current on the line drops below a threshold.
• The current and voltage on the line drop below a threshold.
The open pole feature uses signals defined by the breaker control, distance, and trip output
features. Voltage supervision can be used only with wye VTs on the line-side of the
breakers.
For convenience, the position of the breaker poles defined in the breaker control feature
and available as FlexLogic™ operands
OOS, and are used by the open pole feature (these operands are also available
BREAKER 1
for breaker 2). For correct operation of the open pole detector, the breaker control, trip
output, and single-pole autoreclose features must be enabled and properly configured.
When used in configuration with only one breaker, breaker 2 should be enabled and the
breaker 2 setting should be "On".
Out of Service
Select the Settings > Protection > Control > Open Pole menu item to access the open
pole detector settings.
BREAKER 1 ?A CLSD
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 7: PROTECTION
through
BREAKER 1 ?C CLSD
and