Overview; Introduction To Elements - GE B90 Instruction Manual

CHAPTER 5: SETTINGS
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 SETTINGS
 INPUTS / OUTPUTS
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 SETTINGS
 TESTING
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5.2 Overview

5.2.1 Introduction to elements

For URs, the term element is used to describe a feature that is based around a comparator. The comparator is provided
with an input (or set of inputs) that is tested against a programmed setting (or group of settings) to determine if the input is
within the defined range that sets the output to logic 1, also referred to as setting the flag. A single comparator can make
multiple tests and provide multiple outputs. For example, the time overcurrent comparator sets a pickup flag when the
current input is above the setting and sets an operate flag when the input current has been at a level above the pickup
setting for the time specified by the time-current curve settings. All comparators use analog actual values as the input.
An exception to this rule is digital elements, which use logic states as inputs.
Elements are arranged into two classes, grouped and control. Each element classed as a grouped element is provided with
six alternate sets of settings, in setting groups numbered 1 through 6. The performance of a grouped element is defined by
the setting group that is active at a given time. The performance of a control element is independent of the selected active
setting group.
The main characteristics of an element are shown on a logic diagram. This includes the inputs, settings, fixed logic, and the
output operands generated. The previous chapter explains how to read a logic diagram, and the abbreviations used in a
diagram are defined in the Abbreviations chapter.
Some settings are specified in per-unit (pu) calculated quantities:
pu quantity = (actual quantity) / (base quantity)
B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
 MONITORING
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 ELEMENTS
 CONTACT INPUTS
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 VIRTUAL INPUTS
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 CONTACT OUTPUTS
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 VIRTUAL OUTPUTS
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 RESETTING
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 DIRECT INPUTS
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 DIRECT OUTPUTS
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TEST MODE
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FUNCTION: Disabled
TEST MODE FORCING:
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On
 FORCE CONTACT
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 INPUTS
 FORCE CONTACT
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 OUTPUTS
See page 5-185
See page 5-190
See page 5-192
See page 5-193
See page 5-196
See page 5-196
See page 5-197
See page 5-197
Range: Disabled, Isolated, Forcible
See page 5-201
Range: FlexLogic operand
See page 5-202
See page 5-202
See page 5-203
OVERVIEW
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