GE D90 Plus Instruction Manual page 23

CHAPTER 2: PRODUCT DESCRIPTION
Overfrequency and underfrequency protection
Overcurrent functions
Autoreclose
Breaker failure
Multi-breaker configurations
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
The multiple stages of underfrequency and overfrequency elements can be used to initiate
load shedding or remedial action schemes or frequency-based load restoration schemes
during lack of generation in the network or due to sudden load drops. When combined
with the advanced automation capabilities of the D90
schemes can be built.
For additional information, refer to:
Underfrequency on page 361
Overfrequency on page 363
Plus
The D90 provides overcurrent functions for phase, neutral, and ground that can run in
parallel with distance protection or can be programmed to provide primary protection
under conditions when distance elements are blocked during fuse-failure conditions.
Functions include
• Instantaneous and timed overcurrent elements for phase, neutral, ground, and
negative-sequence protection
• Directional supervision is available for phase, neutral, and negative-sequence
elements
• Time overcurrent elements can be set individually to use IEEE, IEC, or custom
FlexCurves
For additional information, refer to:
Current elements on page 229
Plus
The D90 provides multi-shot autoreclosing for single-pole or three-pole autoreclose on
all types of faults with independently programmable dead times for each shot.
Autoreclosing also can be dynamically blocked by user-programmable logic. Four different
autoreclose modes are available, enabling the user to select the reclosing mode of their
practice.
For additional information, refer to:
Autoreclose on page 338
Plus
The D90 can be used to carry out fully independent breaker failure protection over the
breakers associated with the line when connected to a substation with a breaker-and-a-
half or ring bus arrangement. The D90
digital inputs and outputs, and elements to perform two independent breaker failure
functions.
For additional information, refer to:
Breaker failure on page 276
Plus
The D90 supports multi-breaker busbar configurations, such as breaker-and-a-half and
ring bus arrangements, providing dual breaker autoreclose, dual synchrocheck elements,
and dual independent breaker failure elements.
Plus
, flexible special protection
Plus
provides the required current source inputs,
PRODUCT DESCRIPTION
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