GE B90 - Overview; Introduction to Elements

CHAPTER 5: SETTINGS OVERVIEW
B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 5-3
5
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.
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)

 MONITORING
 ELEMENTS
See page 5-185
 SETTINGS
 INPUTS / OUTPUTS

 CONTACT INPUTS

See page 5-190

 VIRTUAL INPUTS

See page 5-192

 CONTACT OUTPUTS

See page 5-193

 VIRTUAL OUTPUTS

See page 5-196

 RESETTING

See page 5-196

 DIRECT INPUTS

See page 5-197

 DIRECT OUTPUTS

See page 5-197
 SETTINGS
 TESTING

TEST MODE
FUNCTION: Disabled
Range: Disabled, Isolated, Forcible
See page 5-201

TEST MODE FORCING:
On
Range: FlexLogic operand
See page 5-202

 FORCE CONTACT
 INPUTS
See page 5-202

 FORCE CONTACT
 OUTPUTS
See page 5-203
An exception to this rule is digital elements, which use logic states as inputs.