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. The SEL-547 product flyer figures show examples of the SEL-547 "in action" at the transfer switch site and at an individual generator site. Other applications and scenarios are possible.
System Islanding Protection–Quickly detect local system disturbances and trip the transfer switch to separate the utility supply from the load. The SEL-547 Distributed Generator Interconnection Relay is a voltage-based protective relay with over-/underfrequency and over-/undervoltage elements to trip for local system “islanding” or system-wide voltage or frequency disturbances.
Directional Power Protection–Detect directional power flow problems, and quickly disconnect the utility supply from the load and the distributed resource. The directional power element trips for power export violations or generator “motoring.”
Synchronism Check Functionality–Protect both the generator and the grid from damage caused by an out-of-phase close. A synchronism check element detects healthy voltage, frequency, and angle, and supervises breaker/switch closing.
Renewable Generation Application–Apply the SEL-547 to small-scale wind and other renewable generation installations at the point of common coupling between the utility and the source.