Product Description; Overview - GE B90 Instruction Manual

B90 Low Impedance Bus Differential System
Chapter 2: Product description

Product description

This chapter outlines the product, order codes, and specifications.
2.1 Product description

2.1.1 Overview

The B90 Low Impedance Bus Differential System is a microprocessor-based architecture that provides protection and
metering for busbars with up to 24 feeders. The B90 protection system is a centralized architecture built on one B90 IED as
per requirements of a particular application. The IED is a full-featured B90 and as such can be accessed and programmed
individually. Protection and supervisory functions of the B90 include:
• Multi-zone differential protection with both restrained (percent, biased) and unrestrained (unbiased, instantaneous)
functions incorporated. Differential protection is fast (typical response time: ¾ of a power cycle; maximum response
time: 1 power cycle) and secure. Security is achieved by using fast and reliable CT saturation detection algorithm and
a second, phase comparison operating principle.
• Check-zone functionality is provided by programming one of the differential zones to enclose the entire bus
• Dynamic bus replica functionality and multi-zone protection allowing application of the B90 to multi-section re-
configurable busbars
• Isolator monitoring feature monitors up to 48 isolators from the B90 IED
• End fault protection (dead zone protection) is provided for up to 24 breakers
• CT trouble monitoring function is provided for each zone of differential protection
• Breaker fail function is provided for up to 24 breakers
• An instantaneous overcurrent function is available per each current input of the B90 system
• A time overcurrent function is available per each current input of the B90 system for backup protection
• An undervoltage function is provided per each voltage input of the B90 system for supervision purposes
Voltage and current metering is built into the relay as a standard feature. Current parameters are available as total
waveform RMS magnitude, or as fundamental frequency only RMS magnitude and angle (phasor).
Diagnostic features include an event recorder capable of storing 1024 time-tagged events and oscillography capable of
storing up to 64 records with programmable trigger, content, and sampling rate. The internal clock used for time-tagging
can be synchronized with an IRIG-B signal, using the Simple Network Time Protocol (SNTP) over the Ethernet port, or using
the Precision Time Protocol (PTP). This precise time stamping allows the sequence of events to be determined between the
B90 IEDs and throughout the system. Events can also be programmed (via FlexLogic
B90 LOW IMPEDANCE BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
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equations) to trigger oscillography
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