Product Description; Introduction; Overview - GE L60 Instruction Manual

2 PRODUCT DESCRIPTION

2 PRODUCT DESCRIPTION 2.1INTRODUCTION
The L60 Line Phase Comparison Relay 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, mainte-
nance, and analysis. The L60 integrates received pulses on a sample-per-sample base, similar to the analog phase-com-
parison 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 set-
ting. The L60 supports 2 and 3-terminal applications, can be used for single- and three-pole tripping applications, and sup-
ports 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.
Typical two and three-terminal applications are shown below.
GE Multilin L60 Line Phase Comparison Relay

2.1 INTRODUCTION

2.1.1 OVERVIEW

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