Evaluation and validation of Norton approaches for nonlinear harmonic models

Abstract

Distorted currents and voltages are an increasing problem in electrical power networks. Primarily, they are caused by loads and decentralized power supply units which are connected by power electronic interfaces. In order to analyze the effects of a widespread use of such nonlinear appliances, nonlinear models have to be developed. Beside the current source model (CSM), which is suitable only for one specific voltage distortion, the Norton approaches are one of the most common approaches in frequency domain. In this paper, the classic Norton model (NM) and the advanced coupled NM are calculated based on various measurement sets and analyzed regarding their practical applicability in harmonic studies. The limitations of application are emphasized and suitable measurement sets for the calculation of the model parameters are evaluated.

Bivariate stochastic model of current harmonic analysis in the low voltage distribution grid

“…5 represent the mathematical form of the NC model. The verification and comparison of frequency-domain models are presented in [12,13].…”

“…Therefore, a joint or bivariate probabilistic approach is more effective where the estimated variable depends on the probability density function of two variables. In [10], the load current for residential buildings was estimated using beta bivariate distributions.In [11,12], the joint normal distribution (JNB) was employed for the forecasting of harmonic emissions. The parameters of the normal joint distribution, σ (standard deviation) and μ (mean value) are calculated by Eq.…”

Data‐driven robust extended computer‐aided harmonic power flow analysis

“…For this purpose, data acquired from field measurements by staff and partners of the Power Disturbance and Signalling laboratory of University of Alberta, Edmonton, Canada, have been used in this study. The coupled harmonic models have been constructed based on the recursive least squares estimation (RLSE), essentially improving on the ordinary least squares estimation (OLSE) approach discussed in [1, 3]. For improved readability, a brief discussion on the OLSE as well as RLSE harmonic models and how the RLSE model was synchronised with the proposed harmonic assessment method is shown.…”

“…The high uptake of power electronic‐based loads in electricity distribution systems has necessitated the development of harmonic assessment tools and their improved versions in recent times [1–6]. Some of the methods have been extended to study the network operating conditions in the presence of harmonic pollutions [7, 8].…”

Residential Harmonic Injection Models Based on Field Measurements

“…NL loads can be simulated as ideal current sources, either neglecting the influence that distorted voltages may have on injected currents [18] or considering it [19]. NL loads can also be modeled as coupled or uncoupled Norton equivalent models ( [20], [21] or [22]- [24] respectively).…”