Abstract
Wind generators are exposed to numerous destructive forces such as lightning and are therefore vulnerable to these phenomena. To evaluate the transient behavior of a wind power plant during direct and indirect strikes, modeling of all relevant components is required. Among the protective and control components of wind turbines, the grounding system is the most important element for protection against lightning strikes. This paper examines the impact of nonlinear soil ionization behavior and frequency dependency on a wind turbine in order to model a sufficient protection scheme to reduce overvoltage and make the system tolerable against transitions. The high frequency models of other equipment such as transformers, horizontal conductors, vertical rods, surge arresters and underground cables must also be taken into account to design the grounding system. Our Proposed Modified Grounding Scheme (PMGS) is to reduce the maximum transient overvoltages. We simulate the model in a restructured version of the Electromagnetic Transient Program (EMTP-RV) software to examine the effectiveness of the system. We then apply the simulated results to pair of turbines that are interconnected with a frequency-dependent cable. We carry out the simulation for direct and indirect lightning strikes. The results indicate that the MGS can lead to considerably more than a 50% reduction in transient voltages for lightning and thus leads to more reliable networks.
Highlights
An ongoing concern about wind generators [1] and wind farms is how to protect them against harsh environmental conditions [2]
For the frequency-dependent distributed parameters grounding model, the rod is divided into N segments, where each segment is a part of the R-L-Cbranch with similar parameters.This study assumes that each segment is divided into three parts with a length of Unlike other research discussed in this article, this study addresses the nonlinear resistance behavior of the grounding rod to accurately obtain the performance of the rod in less conductive soil
The information shown in the tables indicates that despite the high overvoltages during lightning, the peak rates decrease by half in the Proposed Modified Grounding Scheme (PMGS) model, which is much more reasonable and safer for the wind turbines’ electric and electronic equipment compared to previous models
Summary
An ongoing concern about wind generators [1] and wind farms is how to protect them against harsh environmental conditions [2]. In [26], the authors examine the behavior of wind turbines through three different models that are based on constant resistance, nonlinear resistance and frequency-dependent resistance to obtain a proper grounding scheme for lightning strikes. The authors of [28,29] study direct and indirect strikes in a small wind farm To facilitate their simulation, they assume that the grounding system is a nonlinear resistance rod and that soil ionization is the only effective parameter for grounding protection. We consider a transient voltage study of a wind turbine [29] that considers high frequency models for all relevant components of the pair of turbines, such as transformers, vertical rods, horizontal conductors, Surge Arresters (SAs) and Frequency-Dependent (FD) cables.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
