Summary
Transformerless string inverters afford a number of important advantages in commercial PB projects owing to their compact size, light weight, and ease of installation and maintenance. Their use in distributed system designs yields additional advantages, particularly the increase in energy production enabled by having the MPPT occur at what would be the combiner box level in a centralized system design.
These advantages make the use of transormerless string inverters viable even in systems where a step-up or -down transformer is required. Transformers are commonly used in many power distribution applications. The use of a transformer is the application has its own set of advantages, including the ability to provide isolation with the grid, and the potential for significantly reducing wiring cost by collecting the AC at 480 Vac and maximizing 490 V wiring distances before stepping it down to 208 wiring distances before stepping it down to 208 Vac. Isolation transformer can be used in the AE 3TL string inverters in all cases, however Advanced Energy recommends the use of an autotransformer for a WYE secondary due to the advantages of efficiency and cost.
Advanced Energy's 480V 3TL three-phase string inverter also has its own set of additional and unique advantages. The patented UltraEta drive provides industry-leading high power ouput across all array voltages, while support for high DC:AC ratios enables even greater power production in many systems. The AE 3TL series also provides industry-leading reliability and efficiency (Califorania Energy Commission rating of 97.5-98.0%), and helps minimize system costs with both 600 Vdc and 1000 Vdc imput options available in four models ranging from 12kW to 23kW. This high efficiency enables the AE 3TL with a step-up of step-sown transformer to achieve higher production compared to many string inverters available with 208 Vac output. Advanced Energy offers inverter and trnsformer packages to help ensure a seam less project design and installation. Contact your Greentech Renewables account manger or apply online for dealer pricing.
