Managing grid stability and power quality in the renewable energy era

The weak grid conditions pose significant threats during fault events as the voltage recovery becomes sluggish and fault clearance is delayed.

As the world rapidly transitions towards a cleaner and more sustainable energy future, India finds itself at the forefront of this transformative journey. With about 30 percent of the country’s current power requirement being met by renewable energy sources, the momentum favours green power. The Indian government has set ambitious targets to triple the renewable energy generation capacity by 2030, aiming for a staggering 500 GW. This mirrors the global ambition to reduce reliance on fossil fuels significantly and progress toward achieving net-zero emissions by 2050.

The integration of large-scale renewable energy (RE) into the grid has brought a new set of technical challenges, particularly regarding grid stability and power quality.

Renewable energy installations, especially solar and wind farms, are typically located in remote areas where the grid is inherently weak, characterised by poor short-circuit ratios and low system inertia. These weak grid conditions pose significant threats during fault events as the voltage recovery becomes sluggish and fault clearance is delayed. Traditional solutions like fixed or automatic capacitor banks are no longer adequate to meet modern grid code requirements, such as Low Voltage Ride Through (LVRT) and High Voltage Ride Through (HVRT), leading to instances of mass tripping. Rajasthan, for example, witnessed over 28 major tripping events in 2022 alone.

Regulatory measures and tech solutions for grid stability

Recognising these vulnerabilities, the Central Electricity Authority (CEA) has mandated the use of Static VAR Generators (SVGs) to provide instantaneous reactive power support. Now, RE developers are required to install SVGs with a capacity equivalent to 33 percent of the plant’s rating to ensure voltage stability and fault clearance. But voltage management is just one part of the puzzle. The issue of power quality, especially the rise in harmonic distortion, has emerged as another significant concern.

Traditionally, harmonics in the power system were associated with consumer loads and it was believed that generation, transmission and distribution sectors remained relatively clean. However, this assumption no longer holds with the proliferation of inverter-based renewable generation. These Renewable Energy plants contribute lower-order, complex, and higher-order harmonics, sometimes reaching the 49th order. Standard harmonic mitigation solutions that were once sufficient have now become inadequate. Active filters typically target harmonics up to the 13th or 23rd order, while passive filters designed with damping resistors and high-pass capabilities are more suited to handle these newer challenges.

To enforce compliance, the CEA now insists that any plant seeking grid connection must meet IEEE 519 standards for harmonic distortion. This means appropriate filtering solutions must be incorporated, be they passive, active, or hybrid. To streamline implementation and prevent project delays, a technical committee was formed to recommend standardised solutions, allowing for quicker deployments with the flexibility for fine-tuning later. This proactive approach ensures that harmonic mitigation and reactive power compensation systems are in place before any plant is commissioned.

Balancing the energy mix for a stable transition

Adding to the complexity is the changing nature of demand.

The rise of energy-intensive harmonic-rich sectors such as data centres, AI, and cryptocurrency mining has further pressured the grid’s power quality. Addressing these challenges demands robust and intelligent engineering interventions across the generation and consumption ends. Even as RE capacity rises, the importance of thermal generation cannot be dismissed in the short to medium term. Conventional plants provide vital grid inertia and base load and peak lead stability. With electricity demand projected to grow significantly, the government anticipates an additional 80 GW thermal capacity by 2031. This is a pragmatic step to ensure a reliable 24/7 power supply during the transition.

India and China remain among the largest contributors to new RE capacity worldwide. With strong policy frameworks, skilled engineers and comprehensive grid codes, the country is not just keeping pace with global standards. Still, it also sets examples for coordinated grid planning and execution. While the journey is challenging, the direction is right, and the commitment to a greener, more stable power system is unwavering.