Features - GE L90 Instruction Manual
Ur series line current differential system
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Also See for L90:
- Instruction manual (900 pages) ,
- Communications manual (532 pages) ,
- Instruction manual (486 pages)
Table of Contents
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2 PRODUCT DESCRIPTION
LINE CURRENT DIFFERENTIAL:
•
Phase segregated, high-speed digital current differential system.
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Overhead and underground AC transmission lines, series compensated lines.
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Two-terminal and three-terminal line applications.
•
Zero-sequence removal for application on lines with tapped transformers connected in a grounded wye on the line
side.
•
GE phaselets approach based on the Discrete Fourier Transform with 64 samples per cycle and transmitting two time-
stamped phaselets per cycle.
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Adaptive restraint approach improving sensitivity and accuracy of fault sensing.
•
Increased security for trip decision using disturbance detector and trip output logic.
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Continuous clock synchronization via the distributed synchronization technique.
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Increased transient stability through DC decaying offset removal.
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Accommodates up to five times CT ratio differences.
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Peer-to-peer (master-master) architecture changing to master-slave via DTT (if channel fails) at 64 kbps.
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Charging current compensation.
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Interfaces direct fiber, multiplexed RS422, IEEE C37.94, and G.703 connections with relay ID check.
•
Per-phase line differential protection direct transfer trip plus eight user-assigned pilot signals via the communications
channel.
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Secure 32-bit CRC protection against communications errors.
•
Channel asymmetry (up to 10 ms) compensation using GPS satellite-controlled clock.
BACKUP PROTECTION:
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DTT provision for pilot schemes.
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Five zones of distance protection with six pilot schemes, power swing blocking and out-of-step tripping, line pickup,
and load encroachment.
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Two-element time overcurrent and two-element instantaneous overcurrent directional phase overcurrent protection.
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Two-element time overcurrent and two-element instantaneous overcurrent directional zero-sequence protection.
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Two-element time overcurrent and two-element instantaneous overcurrent negative-sequence overcurrent protection.
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Undervoltage and overvoltage protection.
ADDITIONAL PROTECTION:
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Breaker failure protection.
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Stub bus protection.
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VT and CT supervision.
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GE Multilin sources approach allowing grouping of different CTs and VTs from multiple input channels.
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Open pole detection.
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Breaker trip coil supervision and seal-in of trip command.
•
FlexLogic allowing creation of user-defined distributed protection and control logic.
CONTROL:
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One and two breaker configuration for breaker-and-a-half and ring bus schemes, pushbutton control from the relay.
•
Auto-reclosing and synchrochecking.
•
Breaker arcing current.
GE Multilin
L90 Line Current Differential System
2.1 INTRODUCTION
2.1.2 FEATURES
2
2-3
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