Product Description; Introduction; Overview - GE t60 Instruction Manual

2 PRODUCT DESCRIPTION

2 PRODUCT DESCRIPTION 2.1INTRODUCTION
The T60 Transformer Protection System is a microprocessor-based relay for protection of small, medium, and large three-
phase power transformers. The relay can be configured with a maximum of four three-phase current inputs and four ground
current inputs, and can satisfy applications with transformer windings connected between two breakers, such as in a ring
bus or in breaker-and-a-half configurations. The T60 performs magnitude and phase shift compensation internally, eliminat-
ing requirements for external CT connections and auxiliary CTs.
The percent differential element is the main protection device in the T60. Instantaneous differential protection, volts-per-
hertz, restricted ground fault, and many current, voltage, and frequency-based protection elements are also incorporated.
The T60 includes sixteen fully programmable universal comparators, or FlexElements™, that provide additional flexibility
by allowing the user to customize their own protection functions that respond to any signals measured or calculated by the
relay.
The metering functions of the T60 include true RMS and phasors for currents and voltages, current harmonics and THD,
symmetrical components, frequency, power, power factor, and energy.
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 or via the SNTP protocol over the Ethernet port. 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 troubleshooting time and simplify report generation in the event of a sys-
tem fault.
A faceplate RS232 port may be used to connect to a PC for the programming of settings and the monitoring of actual val-
ues. A variety of communications modules are available. Two rear RS485 ports allow independent access by operating and
engineering staff. All serial ports use the Modbus RTU protocol. The RS485 ports may be connected to system computers
with baud rates up to 115.2 kbps. The RS232 port has a fixed baud rate of 19.2 kbps. The 100Base-FX Ethernet interface
provides fast, reliable communications in noisy environments. The Ethernet port supports IEC 61850, IEC 61850-90-5,
Modbus/TCP, and TFTP protocols, PTP (according to IEEE Std. 1588-2008 or IEC 61588), and allows access to the relay
via any standard web browser (T60 web pages). The IEC 60870-5-104 protocol is supported on the Ethernet port, and DNP
3.0 and IEC 60870-5-104 cannot be enabled at the same time.
The T60 IEDs use flash memory technology which allows field upgrading as new features are added. The following Single
line diagram illustrates the relay functionality using ANSI (American National Standards Institute) device numbers.
Table 2–1: DEVICE NUMBERS AND FUNCTIONS
DEVICE FUNCTION
NUMBER
21G Ground distance
21P Phase distance
24 Volts per hertz
25 Synchrocheck (optional)
27P Phase undervoltage
27X Auxiliary undervoltage
49 Thermal overload (RTD)
50/87 Instantaneous differential overcurrent
50BF Breaker failure
50G Ground instantaneous overcurrent
50N Neutral instantaneous overcurrent
50P Phase instantaneous overcurrent
51G Ground time overcurrent
GE Multilin
DEVICE
NUMBER
51N
51P
59N
59P
59X
67N
67P
68
78
81O
81U
87G
87T
T60 Transformer Protection System

2.1 INTRODUCTION

2.1.1 OVERVIEW

FUNCTION
Neutral time overcurrent
Phase time overcurrent
Neutral overvoltage
Phase overvoltage
Auxiliary overvoltage
Neutral directional overcurrent
Phase directional overcurrent
Power swing blocking
Out-of-step tripping
Overfrequency
Underfrequency
Restricted ground fault
Transformer differential
2
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