Product Description - GE L60 Instruction Manual

L60 Line Phase Comparison System
Chapter 2: Product description

Product description

This chapter outlines the product, order codes, and specifications.
2.1 Product description
The L60 Line Phase Comparison System is part of the Universal Relay (UR) series of products. It provides a simple phase-
comparison principle successfully employed by analog and static relays for many years, along with the significant
advantages of a modern microprocessor-based relay. The phase comparison element performs the following calculations:
• Samples and filters three-phase AC currents at a rate of 64 samples per cycle
• Computes sequence components of the current
• If two CT/VT modules are employed for breaker-and-a-half applications, the relay sums up two currents and performs
the breaker-and-the-half logic calculations
• Forms a composite signal from current components according to a user-defined setting
• Forms local positive and negative squares from the composite signal sent to remote terminal and used locally along
with the channel delay value
• Samples received from remote terminal squares 64 samples per cycle measuring magnitude of the pulse voltage
• Processes received samples to compensate for asymmetry and distortions in the signal
• Detects fault condition with the fault detector
• Compares coincidence of local and remote squares which indicate the presence of internal or external faults
• Detects transient conditions to block the phase comparison function
All processed signals, including transmitted and received pulses, are available in oscillography for commissioning,
maintenance, and analysis. The L60 integrates received pulses on a sample-per-sample basis, similar to the analog phase-
comparison principle, making the relay exceptionally robust on noisy channels. All permissive and blocking schemes, as
well as single and dual phase comparison, are incorporated into a single protection element and can be selected with a
relay setting. The L60 supports two and three-terminal applications, can be used for single- and three-pole tripping
applications, and supports breaker-and-a-half applications. Multiple backup functions include three-zone phase and
ground distance, directional overcurrent, pilot schemes, and current and voltage elements.
Control features include synchrocheck, autoreclosure, and control for two breakers. Monitoring features include CT failure
detector, VT fuse failure detector, breaker arcing current, disturbance detector and continuous monitor.
Diagnostic features include an event recorder capable of storing 1024 time-tagged events, oscillography capable of
storing up to 64 records with programmable trigger, content, and sampling rate, and data logger acquisition of up to 16
channels, with programmable content and sampling rate. The internal clock used for time-tagging can be synchronized
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL 2-1