American Electric Technologies has been a leading provider of power delivery solutions to the traditional and renewable energy industries for more than 65 years.
When AETI designed its 1.0, 1.5, 2.0, 2.5 and 3.0-MW integrated solar inversion systems, utilities identified three design objectives that were not being met: improved efficiency and lower tare loss, long-term reliability and lower integrated installed cost.
Regarding efficiency, more customers are requiring Nationally Recognized Test Laboratory (NRTL) witness-tested California Energy Commission (CEC) efficiency of 97.5% or better. AETI selected the testing voltages of 650, 775 and 900 volts DC, which represent all levels of PV array production for its CEC. AETI also uses unipolar PV arrays with open circuit voltages up to 1100 Volts DC to obtain 10 to 20 percent more power per string, which also saves up to 40 cents per watt in costs over bipolar designs.
Next is long-term reliability. The use of noisy high-velocity fans with air intake from the ground fail because of sucked in dust and grit that destroys bearings. Instead, AETI uses vortex-filtered air intake from above with multiple quiet, small and more reliable fans operating at lower velocity for longer life, greater reliability and far less tare loss than competitive offerings. By combining positive-pressure fan cooling with liquid cooling of the 500-KW, UL-tested power modules, AETI’s inverter operates up to 55°C without output power derating while dramatically extending the life of the power modules. This results in megawatts of production power produced even in the sunniest and hottest climates for many years.
Finally, AETI lowers installed costs by integrating the PV master recombiner, DC & AC disconnect switches, inverters, AC panelboard and MV transformer and switchgear together as one NEMA 3R/4 system. SPW