Evaluating the High Frequency Behavior of the Modified Grounding Scheme in Wind Farms

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.

Minimum Frequency and Voltage Stability Constrained Unit Commitment for AC/DC Transmission Systems

“…Meanwhile, the power's wide transfer would occur and result in transmission lines' power exceeding limits. To avoid the above situation, we introduce constraint (14) in the UC model.…”

“…After HVDC blocking happens, the secondary frequency regulation would adjust real power output of thermal generators to re-establish power balance in a short time. The constraints in Formulas (12)- (14) are added in order to ensure transmission active power within limits. To get augmentation ∆P t G,i and ∆Q t G,i of the real and reactive power of the thermal generators, the linear model of the secondary frequency regulation sub-model is established, which is displayed in Appendix A in detail.…”

“…It can always be triggered by continuous commutation failures or DC lines failures. With such wind power as random source penetrating into the power grid, the HVDC blocked risk will increase [14]. After HVDC transmissions are fed into the power grid, the system operator should prepare much more spinning reserve for dealing with its blocked fault because of HVDC's larger capacity than thermal plants.…”

Electro-Mechanical Design and Creep Analysis of Proposed Enclosure for Flexible Gas Insulated Line Regarding Subsurface Metropolitan Applications of High-Voltage Transmission Lines

“…Proliferating industrialization and urbanization has increased the load demand, which necessitates upgradation along with new installation of power transmission lines (PTLs), in order to ensure higher system reliability and stability [1][2][3][4]. Additionally, development of the smart grid [4,5], integration of renewable energy [6][7][8] and the requirement of interruption free operation [9,10] necessitates implementation of PTLs with in metropolitan areas [11,12]. Literature describes that existing PTLs are comprised of underground cables (UGCs) [7,[13][14][15], overhead lines (OHLs) [2,11,16,17] and gas insulated lines (GILs) [18][19][20][21].…”

Scheduling Distributed Energy Resource Operation and Daily Power Consumption for a Smart Building to Optimize Economic and Environmental Parameters

“…A microgrid (MG) encompasses a portion of an electric power distribution system that is located downstream of the distribution substation. It includes a variety of distributed energy resource (DER) units (such as solar panel and wind turbine [2]) and serves different types of end users of electricity and/or heat [3,4]. Each microgrid is able to supply power to local residents in a small geographical area in a cost-effective manner, by integrating a networked group of renewable generators and storage systems.…”