GE Industrial Solutions POWER LEADER PMCS Network Architecture Guide - Manual (Page 70)

Power Management Control System
Appendix A — IED Descriptions
60
User Interface
• 40-character display and keypad
• One RS232 port, two RS-485 ports
SR745 Transformer Management Relay
The SR745 is a high-speed, multiprocessor based, three-
phase, two- or three-winding, Transformer
Management Relay™ intended for primary protection
and management of small, medium and large power
transformers.
The SR745 combines percent differential, overcurrent,
frequency, and overexcitation protection elements
along with monitoring of individual harmonics and
THD in one economical package.
The SR745 provides a variety of adaptive relaying
features. Adaptive harmonic restraint addresses the
problem of false tripping during inrush. Adaptive time-
overcurrent elements adjust their pickup settings based
on the calculated transformer capability when
supplying load currents with high harmonic content.
Multiple setpoint groups allow you to enter and
dynamically select from as many as four groups of relay
settings to address the protection requirements of
different power-system configurations. Dynamic CT-
ratio mismatch correction monitors the on-load tap
position and automatically corrects for CT-ratio
mismatch. FlexLogic™ allows PLC-style equations based
on logic inputs and protection elements to be assigned
to any of the SR745 outputs.
Simulation mode provides a powerful testing and
simulation feature. This provides the ability to test the
relay operation based on captured or computer-
generated waveform data. These data can be converted
to a digitized format and downloaded into the SR745’s
simulation buffer for playback.
The SR745 also provides its own waveform-capture
function, which records waveform data for faults,
inrush, or alarm conditions.
The autoconfiguration function eliminates the need for
any special CT connections by having all CTs
connected in wye.
Application
• Small, medium, and large power transformers
Protection
• Percent differential
• Adaptive harmonic restraint
• Multiple overcurrent elements
• Adaptive time O/C elements
• Underfrequency
• Frequency rate-of-change
• Overexcitation
• Multiple setpoint groups
Metering and Monitoring
• All currents
• THD and harmonics
• Demand
• Percent of rated load
• Harmonic analysis
• Tap position
• Ambient temperature
• Analog transducer input
• Waveform capture and playback
• Simulation mode
Inputs/Outputs
• Three analog transducer inputs
• 16 digital (logic) inputs
• Seven analog transducer outputs
• Nine control outputs
Additional Features
• FlexLogic™ (programmable logic)
• Auto-configuration (vector group
compensation)
• Dynamic CT-ratio mismatch correction
• RS-232 and RS-485 ports
• Draw-out construction
SR750 Feeder Management Relay
The SR750 Feeder Management Relay is a
microprocessor-based relay intended for the
management and primary protection of distribution
feeders. It can also be used for management and
backup protection of busses, transformers, and power
lines. The relay tracks the power-system frequency and
adjusts the sampling rate to maintain accuracy at all
times.
The relay is specifically designed as an economical
feeder-management system, incorporating the
requirements for protection, control, metering, and
both local and remote user interfaces in one assembly.
This eliminates the need for expensive discrete
components.
Complete overcurrent protection is provided. This
includes phase, neutral, ground, and negative-sequence