Flicker Mitigation via Dynamic Volt/VAR Control of Power-Electronic Interfaced WTGs

Abstract

The emerging trend for electric utilities to install wind based generation on a large scale into distribution networks, employing DFIG or full converter turbine technologies is raising issues for distribution planning engineers with regard to flicker amongst other power quality issues. This paper investigates dynamic Volt/VAR control, a viable flicker mitigation technique which exploits the reactive power capabilities of modern power electronic interfaced wind turbine generators (WTGs). Dynamic Volt/VAR control essentially mitigates flicker by solely dispatching reactive power based on voltage fluctuations within the flicker frequency band. This technique can be incorporated as part of a wind farm multiobjective reactive power control scheme, which facilitates regulating both 1) the voltage level at the point of common coupling (PCC) employing slow acting voltage control or power factor control and 2) the flicker level at the PCC with fast acting dynamic Volt/VAR control. This two-level approach can reduce the wind farm flicker level up to 80 % and maintains the voltage level at the PCC well within acceptable bands. The results presented in this paper focus on a typical 25 kV medium voltage distribution feeder integrating wind based generation on a large scale. The performance of the two-level controller was tested for varying levels of penetration and wind speed conditions. The applicable standards and utility grid code requirements are considered throughout.

Total output power variation of several small wind turbines

“…in the system (Alasooly and Redha, 2010;Blavette et al, 2016) and inrush current at the startup of induction machines (Chen et al, 2016;Leinonen and Laketic, 2018;Rahman et al, 2018), but it is recognized that severe output variation of wind power may also be another cause of voltage flicker (Ammar and Ammar, 2016). Thus, studies to analyze the voltage flicker caused by large-scale WTs have been conducted under numerical simulations (Alaboudly et al, 2013;Ammar and Ammar, 2016;Fooladi and Akbari Foroud, 2016;Hu et al, 2009;Mascarella et al, 2015).…”

Non stationary‐ARMA flicker model for squirrel cage induction generators based wind farms

“…An analytical formulation of the generated aerodynamic torque of a three‐bladed wind turbine including the effects of wind shear and tower shadow is presented in [12]. The proposed model in [12] was utilized in several applications as the volt/var control of power‐electronic interfaced WTGs [13] and reactive power coordination in DFIG based wind farms [14]. A neural network based model for wind turbine flicker emission calculations is presented in [15].…”

“…Estimation of cumulative P st for multiple wind turbines (13) where, P st,i is the flicker severity due to one wind turbine and n indicates flicker summation factor. In case of wind turbines with same rating, n can be calculated by Equation (14).…”

Comparison of Voltage Regulation of a Smart Load for 3 Bus System and 15 Bus System under High Penetration of Wind Energy System

“…Because of the significant variance, true power quality difficulties arise as the admission level of inexhaustible sources rises over time. Different issues arise from the insufficient changing parts of environmentally friendly power sources, such as the difficulty in predicting the framework's power stream, and it will not be difficult to undertake power stream examination midway in the keen lattice frameworks [6]. Further improved load management solutions are required to respond to these expanding features and eccentric nature of environmentally friendly power sources.…”