Impact of Linear Load Modeling on Harmonic Power Flow Results in Distribution Networks

Linear load modeling represents an important step in conducting harmonic analyses. On harmonic frequencies, linear loads do not produce harmonic distortions, but have significant impact on the system's frequency response. In the available literature there are variety of linear load models which consist of different combination of series and/or parallel resistances, inductances and capacitances. In this paper the comprehensive analysis of 8 different linear load models for solving the harmonic power flow (HPF) on the standard IEEE 18-bus network is presented. In order to calculate harmonic components, the decoupled harmonic power flow (DHPF) algorithm is used. It is shown that results obtained using different linear load models can differ by more than 50%. The verification of HPF results is performed by comparison with those obtained using specialized software packages (i.e., ETAP, DIgSILENT and PCFLO).