Determine the background harmonic voltage and current levels. The measurements typically are performed over a period of 1-5 days in order to assure that adequate data is collected to characterize the system operation and for verification of the analytical models. A list of nonlinear loads is compiled and representations of these loads as harmonic generating devices is developed. The motor loads and resistive loads have important impacts on the system frequency response but they are not sources of harmonic distortion. These representations are used in conjunction with the system model to estimate harmonic levels throughout the facility.
Output consisting of magnitude and phase angle for the driving point impedance is produced.
Tabular and graphical results of various switching conditions is prepared so harmonic resonance conditions can easily be identified. If problem conditions are identified at a given bus, filter designs are developed to alleviate the resonance problems. These filter designs should be coordinated closely with the transient analysis. The frequency scan cases identify system conditions that can cause harmonic problems due to resonance conditions. These system conditions are emphasized when evaluating the response to estimated harmonic current injection levels.