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Harmonics Analysis

Harmonics Analysis

Harmonic studies are performed by Arc Flash Advisors to determine the effects of harmonic-producing non linear devices (such as furnaces, large adjustable-speed devices, static VAR compensators and HVDC rectifiers) on other equipment in the system, to determined potential resonance issues. These studies are typically associated with the installation of capacitor banks or reactors, and for designing and evaluating the performance of harmonic filter banks.

Harmonic currents can increase the heating of conductors and transformers to detrimental levels, as well as causing performance interference with some load devices, such as telephone interference. IEEE Standard 519 defines the characteristics of the harmonic distortion that is allowed at the interface point with the utility. A Harmonic Analysis Study will indicate if the power distribution system is in compliance with IEEE Standard 519.

Harmonic Analysis Studies are a prime aid in designing and implementing corrective filter systems for harmonic effect minimization. Study considerations include harmonic effects from power factor correction capacitors, resonance conditions, THD (Total Harmonic Distortion) percentage per IEEE 519, K-Factor calculations to meet UL Standards and ANSI C57.110 procedures.

Compliance: Following the NETA recommendations, the harmonic-analysis study will be performed in accordance with the recommended practices and procedures set forth in ANSI/IEEE 399, IEEE 519, and ANSI C57.110.

Study Report: Following NETA recommendations, the results of the harmonic-analysis study will be summarized in a final report containing the following items:

•Basis, description, purpose, and scope of the study.
•Tabulations of the data used to model the system components and a corresponding one line diagram.
•Descriptions of the scenarios evaluated and the basis for each.
•Tabulations of rms voltages, peak voltages, rms currents, and total capacitor bank loading versus associated equipment ratings. Equipment with insufficient ratings shall be clearly identified for each of the scenarios evaluated.
•Tabulations of calculated voltage-distortion factors, current-distortion factors, and individual harmonics versus the limits specified by ANSI/IEEE 519. Calculated values exceeding the limits specified in the standard shall be clearly noted.