Experimental measurements of energy consumption changes in a wye distribution system serving multiple computer loads as various harmonic solutions are applied

Most older facilities' electrical systems were never designed to handle the harmonic stresses of modern electronic loads. To address these issues, many engineers and facility managers are forced to select from several harmonic solutions. In evaluating these various solutions, considerations must include effectiveness, installation costs, and total cost of ownership. Typically, total cost of ownership will outweigh installation costs. The largest component in total cost of ownership is energy consumption. This work will report results obtained measuring changes in energy consumption brought about by varying distribution system elements for distribution systems supplying single-phase nonlinear loads. The elements that were incorporated in the study include: (1) Various transformer types and impedances including (a) Standard (conventional), (b) K-13, (c) Zig-Zag; (2) Various distribution conductor configurations and lengths; (3) A Harmonic suppression system. Data were collected utilizing a laboratory 15 kVA distribution system. System energy consumption measurements and transformer secondary harmonic measurements provided data to enable evaluation of the various system configurations being studied.