India Explores Grid-Forming Technology To Strengthen Renewable Energy Integration And Grid Stability—Discussion Paper

Grid-India, the Grid Controller of India Limited, has released a detailed discussion paper exploring the role of grid-forming (GFM) technology as India accelerates its transition toward renewable energy. With the country aiming to achieve 500 GW of non-fossil fuel capacity, the power system is undergoing a major shift from traditional synchronous generators to inverter-based resources (IBRs) such as solar and wind power. While this transition is essential for sustainability, it also brings complex stability challenges that require advanced inverter controls.

Historically, the Indian power system has relied on grid-following (GFL) inverters. These devices act as current sources and depend on an existing grid voltage and frequency signal to operate. GFL technology works well in strong grids but often faces difficulties in weak grid conditions, where the connection to the main power system is less robust. In such situations, GFL inverters can become unstable, potentially causing equipment tripping or loss of generation.

GFM technology, however, represents a significant shift by allowing inverters to function as controllable voltage sources. Unlike GFL inverters, GFM devices can autonomously establish and maintain voltage and frequency references. This makes them highly resilient in weak grids and capable of providing “black start” functionality, which enables the restart of a portion of the grid after a total blackout without relying on external power.

The discussion paper includes extensive simulation studies of the all-India power system, with a particular focus on large renewable energy complexes in Rajasthan. The results demonstrate that GFM technology performs significantly better than GFL inverters during and after grid disturbances. One of the most important benefits is the ability of GFM inverters to provide an “inertia-like” response. Traditional grids rely on the rotating mass of large turbines to naturally resist frequency changes during faults. As turbines are replaced by static solar panels, this inertia is lost. GFM inverters can digitally replicate this effect, instantly limiting the rate of change of frequency (RoCoF) and helping prevent system-wide instability.

The research also highlights that GFM inverters improve voltage stability. They reduce the severity of voltage dips during faults and mitigate high-voltage overshoots that can occur after fault clearance in areas with high renewable penetration. The studies indicate that the benefits of GFM technology increase with higher deployment levels, especially when distributed across the grid for system-wide impact.

International examples confirm the practicality of GFM technology. Projects in Australia, Great Britain, Saudi Arabia, and the United States have successfully used GFM in transmission-level applications. In Hawaii, a large-scale GFM battery energy storage system (BESS) has helped stabilize the island grid following the retirement of a major coal plant, demonstrating the commercial viability of the technology.

Looking forward, Grid-India recommends a phased approach for implementing GFM technology. New battery energy storage installations above 50 MW, particularly in remote or weak-grid areas, should include grid-forming capabilities. The paper also stresses the importance of updating Indian grid codes and technical standards to align with international practices. As the power sector reviews these findings, attention will turn to pilot projects and compliance verification to ensure that India’s next-generation grid is both resilient and capable of supporting a green energy future.

This discussion paper signals a major step in preparing India’s power system to handle high renewable energy penetration while maintaining stability, offering a roadmap for integrating advanced inverter technology into the nation’s rapidly evolving energy landscape.