Abstract
Interfacing a weak grid imposes challenges on distributed generators (DGs). These challenges include transient frequency and voltage dynamics that can destabilize the system. Accordingly, this paper investigates the grid stiffness based on different scenarios and the dynamics of a grid feeding DG connected to a weak grid. Moreover, the dynamic effects of the physical and control parameters on the system’s stability are deeply analyzed and evaluated. Specifically, complete mathematical models and graphical representation are carried out to precisely examine the impact of the system parameters on the stability and performance of the DG. Therefore, stable deployment of renewable energy resources into power networks can be achieved as well as an efficient and robust performance of DGs can be ensured when connected to weak grids. The obtained results show the importance of the performed study in optimal sizing and designing the output filter of the inverter and the impact of tuning the control parameters on the system dynamics. As a result, a proper design of system physical and control parameters can be accurately achieved considering all factors affect the system performance. The paper also conducts detailed and elaborated analyses and simulations to evaluate the performance of a PI-controlled RC damped inverter connected to a weak grid. The proposed filter design of the interfacing inverter can significantly extend the integration of DGs into microgrids without requiring complex control schemes or oversized components.
Highlights
A weak grid usually describes a power network with a voltage distortion present at the point of connection (POC) [1]
This work deals with evaluating the dynamic performance of distributed energy resources connected to a weak grid
Through complete modeling of the system and frequency domain analyses, this work reveals the impact of the control and physical parameters on the tracking capability and disturbance rejection of the model on system dynamics
Summary
A weak grid usually describes a power network with a voltage distortion present at the point of connection (POC) [1]. The determination and classification of a grid stiffness are performed essentially based on the grid short circuit ratio (SCR) calculated using the grid impedance values. Small grid impedance values result in a stiff grid with a high SCR. Large values of grid impedance seen at the POC result in a low SCR due to the increased voltage drop at the transmission lines [2,3,4]. While the grid resistance impacts the magnitude of the POC voltage, a large variation in the grid inductance affects the voltage magnitude and creates a phase shift that affects the active power flow at the POC. Increasing grid impedance value significantly affects the performance of the DG control that is tuned according to the known impedance value incorporated in the current control loop
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
