Great River Energy, Elk River Station, Unit Nos. 1 & 2
Elk River, MN
Great River Energy
12300 Elm Creek Boulevard
Maple Grove, MN 55369
The L&S Electric Advanced Excitation System (AES) static excitation system was selected to replace the existing Basler DECS-200 pilot exciters at the Great River Energy’s Elk River Plants’ Unit No. 1 and Unit No. 2 synchronous generators. GRE choose the AES for the comfort they felt in L&S Electric’s excitation engineering expertise, the AES’s advanced monitoring and control features, the L&S Electric provided 24/7 product support, the two (2) year warranty and the commercially available spare parts.
The Unit No. 1 and Unit No. 2 synchronous generators’ rated outputs are 12 MW at 13.8kV and has field requirements of 193 amperes, 250 volts at rated load and 0.85 power factor. The input power to the AES was provided from an excitation power transformer (EPT). The EPT’s ratings are 180kVA, 13,800/480 volts AC, 3-phase, 60 hertz, wye-delta with ±2x2½% primary taps and one (1) RTD in the center winding for over-temperature protection.
The GRE exciters are LS-AES-FS-EXC-DT-400 Static Exciter Systems. Each exciter included the AES’s standard features; a digital excitation controller, a 400-amp, full wave rectifier bridge assembly with redundant fan-cooling, an AC input breaker, AC field flashing, a crowbar with a linear field discharge resistor for over excitation protection, an AC filter, a DC filter, a holding resistor, shaft voltage suppressor, Ethernet IP communications, and a 15-inch color touchscreen (OIT), all in a 2-door, climate controlled, NEMA 12 enclosure with forced ventilation.
The GRE exciters also included the optional field ground monitoring and detection (64F) capabilities.
Additionally, the L&S Electric project provided services including the design and supply of the AES excitation elementary diagrams, the wiring diagrams, the assembly diagrams, operation & maintenance manual, installation engineering, installation supervision services, and the AES commissioning and onsite AES training.
Unit No. 1 was installed April 2016 and Unit No. 2 was installed June 2016