Equivalent Modelling of Wind Farms for Probabilistic Harmonic Propagation Studies

Abstract

This paper investigates the effect of modelling of different aspects of wind farms (WF) as a first step towards development of the equivalent harmonic model initially of WF, and later of other types of converter connected generation, for studies of harmonic propagation and mitigation in power electronics (PE) rich transmission networks. The aim of the study was to establish a set of scaling factors that can be used when modelling the entire WF as a single probabilistic harmonic generator in harmonic propagation studies, considering different WF configurations, weather conditions, harmonic cancellation effects, individual wind generator availability, cable disconnection, and the influence of the non-ideal external grid. The importance of modelling resonance and individual characteristic harmonics on the equivalent modelling of WF has also been established. The results facilitate the assessment of global contribution of PE connected RES to harmonic levels in transmission networks and more generally harmonic propagation studies in large PE rich transmission networks.

Probabilistic Harmonic Estimation in Uncertain Transmission Networks Using Sequential ANNs

“…For each type of harmonic sources, different harmonic injection spectra are utilised, covering different operating conditions. The magnitudes of harmonic injections are randomly sampled within normal distributed pre-defined ranges that are selected based on long-term measurements of the harmonic spectrum of PE interfaced generations [1,20,26]. For all types of harmonic sources, the harmonic angle injections are randomly sampled within a range of (0°, 180°), considering all 2 nd -25 th harmonic orders [26].…”

“…Among those, the harmonic distortion issues, that result in significant financial losses to both network operators and end users is becoming even more pronounced. Although the harmonic distortions and voltage fluctuation are controlled by transmission system operators (TSOs) at present, the increased number of the future PE devices could lead to increase propagation of harmonics into the transmission system and leading to additional uncontrolled harmonic power flows [1,2].…”

Accuracy of Probabilistic Harmonic Estimation in Sparsely Monitored Transmission Networks

“…The ranges of harmonic magnitude injections (Normal distributed) are defined based on long-term measurements [13] of the harmonic spectrum in terms of different types of harmonic sources and individual harmonic orders (2 nd -25 th ). The range of harmonic phase injection is defined as (0°, 180°), applicable for all types of harmonic sources [1,22].…”

“…Power system harmonic distortions are highly associated with the increasing penetration level of power electronic (PE) devices, e.g., renewable generations. In response to the global environmental-friendly policies, there are more and more PE interfaced devices continuously connecting into the large transmission system, leading to additional uncontrolled harmonic power flows and unexpected harmonic issues, thus resulting in significant financial loses to both transmission system operators (TSOs) and customers [1,2].…”

Propagation characteristics and quantification analysis of harmonic current in large‐scale wind farms

“…1 The applications of many power electronic devices make the wide frequency domain harmonic problems increasingly severe in the power system. [2][3][4] Due to the application of power electronic equipment in wind power grid-connected systems, the harmonic oscillation in the wide frequency domain is no longer a local single oscillation problem and is a global complex oscillation problem. [5][6][7] As the resonant circuit no longer limits the harmonic oscillation caused by power electronic equipment, wind farm harmonics spread to all system regions through the transmission network.…”