With the growing uptake of renewable energy, power electronics will play an essential role in maintaining grid stability.
The rapid integration of Inverter Based Resources (IBR) such as wind and solar power generation is transforming the power grid, challenging the traditional reliance on synchronous generators (SGs) for stability. As the share of IBR increases, grid‑forming inverters (GFMs), are emerging as critical components in maintaining a stable and reliable power system.
The role of IBR
Unlike SGs, which impose strict frequency and voltage boundaries, IBR offer greater operational flexibility. Inverters can be broadly classified into two main categories based on their interaction with the grid: grid-forming and grid-following (with grid-supporting capabilities).
Grid-following inverters passively adhere to the grid’s characteristics, often with some grid-supporting capabilities such as providing ancillary services like voltage control. GFM on the other hand, possess the unique capability to independently establish and control the grid’s voltage and frequency, making them indispensable in scenarios with low or no SG presence.
The cornerstone of future grids
GFMs offer several advantages in the evolving power grid. They can emulate the inertial response of SGs, crucial for maintaining frequency stability as RES penetration increases and system inertia decreases. GFMs also enable the formation and operation of microgrids, which are essential for providing reliable power in remote areas and enhancing overall grid resilience.
However, the adoption of GFMs is not without challenges. Their control algorithms are inherently more complex than those of grid-following or grid-supporting inverters, requiring advanced modelling and real-time processing capabilities.
The cost of GFMs can also be higher due to their sophisticated features and high-reliability components. Furthermore, the coordination of multiple GFMs in a grid necessitates careful design and management to prevent adverse interactions and stability issues.
A double-edged sword
The use of multiple GFMs in a power system can bring significant benefits, such as improved grid reliability and resilience due to decentralised control and increased redundancy.
However, it’s important to acknowledge the complexities that arise with multiple GFMs. If not properly coordinated, they can interact negatively, leading to issues like oscillations, frequency instability, and voltage regulation problems.
Additionally, integrating and managing multiple GFMs requires advanced communication and control systems, which can raise concerns about scalability and cost. Therefore, careful management of these factors is crucial to ensure the economic viability of deploying multiple GFMs.
The road ahead
As the power grid transitions towards a future with higher levels of IBR penetration, GFMs are poised to play a pivotal role in ensuring grid stability and reliability.
Their ability to independently form and stabilise the grid offers significant advantages but also presents challenges in terms of control complexity, cost, and coordination. With continued research and technological advancements, GFMs are expected to become increasingly prevalent in future power grids, facilitating the seamless integration of renewable energy sources and contributing to a cleaner and more sustainable energy future.
Understanding Power System Dynamics with High Levels of Grid-forming Inverters is a research project funded by the Reliable, Affordable, Clean, Energy (RACE) for 2030 Cooperative Research Centre and in collaboration with Curtin University, Powerlink, and Queensland University of Technology (QUT).
Featured image: SritanaN/shutterstock.com
