Use of Actual and Reference Impedances in Two Harmonic Emission Assessment Methods

This paper evaluates two commonly used methods that require information either on network harmonic impedance (IEC method), or on both network and customer installation harmonic impedances (voltage harmonic vector, VHV, method) for determining network and customer contributions to the total voltage harmonic distortion. The paper compares results of the IEC and VHV methods obtained with actual and reference impedances, which are also cross-correlated with the third method (voltage-only method, VoM), which does not rely on the use of either network or customer impedances. The results are obtained for a MV benchmark network model (BNM) proposed by IEEE-PES TF, which features network background distortion, harmonic resonance, different compensator types and customers with both linear and nonlinear loads. The results of VoM, IEC and VHV methods are discussed and illustrated for a range of harmonic interactions, with particular attention paid to the analysis of resonance conditions in the BNM.