Product Description; Introduction; Overview - GE L60 Instruction Manual

2 PRODUCT DESCRIPTION

2 PRODUCT DESCRIPTION 2.1INTRODUCTION
The L60 Line Phase Comparison System 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 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, direc-
tional 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 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 throughout the system. Events can also
be programmed (via FlexLogic™ equations) to trigger oscillography data capture which may be set to record the measured
parameters before and after the event for viewing on a personal computer (PC). These tools significantly reduce trouble-
shooting time and simplify report generation in the event of a system fault.
Several options are available for communication. A faceplate RS232 port can be used to connect to a computer for the pro-
gramming of settings and the monitoring of actual values. The RS232 port has a fixed baud rate of 19.2 kbps. The rear
RS485 port allows independent access by operating and engineering staff. It can be connected to system computers with
baud rates up to 115.2 kbps. All serial ports use the Modbus RTU protocol. The 100Base-FX or 100Base-T Ethernet inter-
face provides fast, reliable communications in noisy environments. The Ethernet port supports IEC 61850, Modbus/TCP,
and TFTP protocols, PTP (according to IEEE Std. 1588-2008 or IEC 61588), and allows access to the relay via any stan-
dard web browser (L60 web pages). The IEC 60870-5-104 protocol is supported on the Ethernet port. DNP 3.0 and IEC
60870-5-104 cannot be enabled at the same time. The Ethernet port also supports the Parallel Redundancy Protocol (PRP)
of IEC 62439-3 (clause 4, 2012) when purchased as an option.
Settings and actual values can be accessed from the front panel or EnerVista software.
Typical two-terminal and three-terminal applications are shown below.
GE Multilin L60 Line Phase Comparison System

2.1 INTRODUCTION

2.1.1 OVERVIEW

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