Project Description

SEL-547 Distributed Generator Interconnection Relay

SEL-547 Distributed Generator Interconnection Relay

Apply the flexible SEL-547 at the transfer switch site (interconnection point between the utility and the customer) and at each individual generator site. When the SEL-547 at the transfer switch site detects utility supply problems, it separates the customer system from the utility supply. When the SEL-547 at an individual generator site detects a system problem that could adversely affect the generator, it separates the individual generator from the rest of the system.

Functional Overview

 SEL-547 Functional Overview
25 Synchronism Check
27 Undervoltage
32 Directional Power
40 Loss-of-Field
47 Reverse-Phase Sequence Voltage
59 Overvoltage
81 (O,U) Frequency (Over, Under)
SER Sequential Events Recorder


Front- and Rear-Panel Diagrams

SEL-547 Front Panel SEL-547 Top Panel
Front Top


Protection and Control Elements Required by IEEE 1547

  • Four undervoltage elements (device 27)
  • Four overvoltage elements (device 59)
  • Four over-/underfrequency elements (device 81)
  • Directional power element (device 32)
  • Synchronism check element (device 25)

Modbus® and SEL Communications Interface

  • Modbus communications protocol interfaces the SEL-547 to outside communications networks.
  • Integrate with SEL communications processors using SEL Fast Meter and Fast Operate messages.

Additional Elements for System Protection and Restoration

  • Over-/undervoltage or over-/underfrequency elements operate for local system islanding or system-wide voltage/frequency disturbances.
  • Directional power element operates for power export violations or generator motoring.
  • Synchronism check element detects healthy voltage, frequency, and angle, and supervises breaker/switch closing.



300G 700G 547
Generator Protection
Induction Motor Protection
Breaker Failure Protection f f
Equipment Thermal Monitoring + +
Generator Intertie Protection
Synchronism Check + +
Integrated Synchronizer +
21P Phase Mho or Compensator Distance +
24 Overexcitation (Volts/Hertz)
27/59 Under-/Overvoltage
32/37 Directional/Underpower Elements
40 Loss-of-Field
46 Current Unbalance
47 Phase Reversal
49 Thermal
50 (P,N,G) Overcurrent (Phase, Neutral, Ground)
50Q Negative-Sequence Overcurrent
51 (N,G) Time-Overcurrent (Neutral, Ground)
55 Power Factor f f
60 Loss-of-Potential
64G 100 Percent Stator Ground +
64F Field Ground
67 (N,G) Directional Overcurrent (Neutral, Ground)
78 Out-of-Step
81 Over-/Underfrequency
87 Current Differential + +
87G Restricted Earth Fault
Separate Neutral Overcurrent
Inadvertent Energization f f
Flashover Protection f f
SELogic Control Equations/Remote Control Switches
Nonvolatile Latch Control Switches
Multiple Settings Groups
Station Battery Monitor
Breaker Wear Monitor
Event Report (Multicycle Data)/Sequential Events Recorder
Demand Meter
Load Profile Report
RTD (Resistance Temperature Detector) Inputs + +
Ethernet +
IEC 61850 +
Simple Network Time Protocol (SNTP)
Modbus TCP
Modbus RTU Outstation +
Synchrophasors With IEEE C37.118 Protocol
Mirrored Bits Communications
DeviceNet +
Accepts Wye or Open-Delta Voltage Transformers +
Connectorized (Quick Disconnect) Available +
Standard Feature
+ Model Option
f This function may be created using settings

Product Literature