Product Description - GE T35 Instruction Manual

T35 Transformer Protection System
Chapter 2: Product description

Product description

This chapter outlines the product, order codes, and specifications.
2.1 Product description
The T35 Transformer Protection System is part of the Universal Relay (UR) series of products. It is a microprocessor-based
relay for protecting small, medium, and large three-phase power transformers involved in complicated power system
configurations. The relay is available with two to six banks of three-phase inputs: either CTs or CTs and VTs.
Typical T35 applications include:
• Transformers with windings connected between two or more breakers
• Transformers with windings without associated breakers, where the only available ones are those on buses, lines, or
feeders
The percent and instantaneous differential elements are the primary protection elements. The backup protection
elements, such as instantaneous overcurrent, can be expressed in fully configurable FlexElements™. The relay can also be
configured to protect transformers with any phase shift between the windings and handle up to 32 times the ratio
mismatch.
Voltage, current, and power metering are built into the relay as standard features. Current parameters are available as
total waveform root mean square (RMS) magnitude, or as fundamental frequency only RMS magnitude and angle (phasor).
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, as well as 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 that can be set to record the
measured parameters before and after the event for viewing on a computer. These tools significantly reduce
troubleshooting time and simplify report generation in the event of a system fault.
Several options are available for communication. An RS232 port (USB port with the graphical front panel) can be used to
connect to a computer to program settings and monitor of actual values. 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 IEC 60870-5-103 protocol is supported on the RS485 interface. IEC 60870-5-103,
DNP, and Modbus cannot be enabled simultaneously on this interface. Also only one of the DNP, IEC 60870-5-103, and IEC
60870-5-104 protocols can be enabled at any time on the relay. When the IEC 60870-5-103 protocol is chosen, the RS485
port has a fixed even parity and the baud rate can be either 9.6 kbps or 19.2 kbps. The 100Base-FX Ethernet interface
provides fast, reliable communications in noisy environments. The Ethernet port supports IEC 61850, Modbus/TCP, TFTP,
T35 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL 2-1