Ahlstom-Monksjo (Expera) Thilmany Mill
Alvar Aallon katu 3 C
FI-00101 Helsinki, Finland
The L&S Electric Advanced Excitation System (AES) full static excitation system was selected to replace the existing G.E. SCT/PPT Static Exciter Regulator at the Expera Specialty Solutions, Thilmany Plant’s Unit No. 2 synchronous generator. Expera choose the AES for its advanced monitoring and control features, the comfort they felt in L&S Electric’s excitation engineering expertise, the L&S Electric provided 24/7 product support, the competitive price, the two (2) year warranty, and the commercially available spare parts.
The Unit No. 2 synchronous generator’s rated output is 11 MW at 12kV and has field requirements of 272 amperes, 125 volts at rated load and 0.89 power factor. The input power to the AES was provided from an excitation power transformer (EPT) with ratings of 68kVA, 14,000/134 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 Expera exciter is a LS-AES-FS-EXC-DT-400 Static Exciter System. The 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 Expera exciter 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 (cut-ins), installation supervision services, and the AES commissioning with onsite AES training.
The unit was installed August 2018.