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

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

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.