In a peer study, PowerCalc was used to review the installation of a backup generator.
The electrical design for the installation specified ten (10) 112.5 kVA transformers. That's a lot of transformers, an oversight easily identified by a seasoned professional. This specification is about three times (3X) the amount of electrical power typically designed for such a facility (10W / SF instead of 3 W / SF).
Running the same design through PowerCalc resulted in a reduction of this specification for transformers instead to ten (10) 30 kVA to 45 kVA transformers. This "downsizing" resulted in over $2,000,000 in savings by not only reducing the size of the transformers, but also the related conductors and conduits.
For all involved in construction every day, these types of mistakes are not uncommon. These issues arise from the current electrical design practice of using "rules of thumb", makeshift spreadsheets, and software that "designs" from the top-down (estimating the total electrical load at the start of design). The accurate design approach is to instead know the actual electrical demand load by adding electrical loads from the circuit to the facility's connection to the power grid (bottom-up). This bottom-up approach is PowerCalc's patented design methodology.
In contasting approaches, guestimating the size of the electrical load in conjunction with pre-sets for panelboard sizes, transformers, equipment disconnects, feeders, and overcurrent protection devices at the start of the project may lead to an inaccurate baseline on which to build the electrical engineering design instead of an accurate calculation of the Total Electrical Load based on the project's actual electrical demand.
This distinction in approach is important as electrical equipment that is (1) oversized results in increased costs for the developer and/or owner for expensive electrical equipment as well as wasted electrical energy and (2) undersized results in a potentially increased risk to safety (fires).
FYI: the initial design was done by an engineering consulting firm ranked in the top 100 nationally using leading electrical design software with a top-down design approach.
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