THE PQI CALCULATOR™

In 2003, e-Rated Transformer Corporation developed a sophisticated computer program that calculates any transformer’s efficiency under any non-linear load condition. This program is now the basis for an upgraded version of The PQI CalculatorÔ, shown in Figure 1.

The PQI CalculatorÔ

Figure 1

The PQI CalculatorÔ will allow an engineer to compare the performance of a Distribution TransFiltersÔ and any conventional or K-Rated distribution transformer.

Main Data Entry

Figure 2

The programmer then has the option of entering either the transformers’ efficiencies, at a specific load, Figure 3, or their losses, Figure 4.

Losses Figure 4

The programmer must then enter the load’s harmonic current magnitudes. The default values shown are typical for single-phase, non-linear switch-mode power supplies, as per IEEE Std 519-1992.

Harmonics Figure 5

The programmer then has the option of entering the transformers’ Custom Load profile, Figure 6, or any one of four NEMA PT 1-2002 profiles at a specified load level, Figure 7.

Custom Load Figure 6

NEMA TP 1-2002 Figure 7

COMPUTATIONS

Once these selections have been made, The PQI CalculatorÔ will compute all values contained in the red and green windows, and generate loss and efficiency curves for both transformers under linear and non-linear load conditions, Figures 8, 9 & 10.

75kVA Conventional Transformer vs. 75kVA Distribution TransFilterÔ Figure 8

75kVA Conventional Transformer vs. 75kVA Distribution TransFilterÔ Figure 9

75kVA Conventional Transformer vs. 75kVA Distribution TransFilterÔ Figure 10

With reference to Figure 1, The PQI CalculatorÔ shows the various outcomes when comparing the performance of two 75kVA transformers in a Custom Load scenario.

In order to display the Annual Savings, ROI and Payback, in a substitution and replacement scenario simultaneously, the programmer has entered the Capital Cost for both transformers plus an Installation Cost. Ordinarily, the programmer would enter (i) either the two Capital Costs, for a substitution scenario or (ii) the Capital Cost of the Distribution TransFilterÔ and its Installation Cost, for a replacement scenario.

The Annual Energy Savings, ROI and Payback, calculated by The PQI CalculatorÔ, are based on transformer performance only.

System performance

The reduction of harmonic currents and voltages in the remaining elements of the electrical distribution system will further reduce its ‘penalty losses’ and increase its efficiency. In medium to large distribution systems, these additional financial benefits can equal or exceed those produced by the application of Distribution TransFiltersÔ in isolation.

The PQI Solution™

Power Quality internationAL, inc. uses The PQI CalculatorÔ to optimize the financial benefits of The PQI SolutionÔ. This service is available on a free-of-charge basis. Please call PQI at (888) 539-7712 for additional information.