Khavda grid disturbance causes 9,000 MW generation loss, largest single-event outage in Indian grid history
A major grid disturbance in the Khavda Renewable Energy (RE) complex on May 13, 2026 resulted in the largest single-event generation loss recorded in the history of the Indian grid, according to a presentation made by GRID-INDIA before the National Committee on Transmission (NCT).
The disturbance occurred at 14:09 hrs and led to the complete outage of three major pooling stations: KPS-1, KPS-2 and KPS-3. The stations together had an installed capacity of 15.9 GW, comprising 14.8 GW of Variable Renewable Energy (VRE) and 1.1 GW of Battery Energy Storage Systems (BESS).
Sequence of events
According to the preliminary analysis based on Phasor Measurement Unit (PMU) data, the sequence of disturbances began at around 14:02 hrs, when a voltage dip was observed in the Khavda complex. The event was likely linked to a fault on the 400 kV Indore-Asoj line and may have been compounded by Low Voltage Ride Through (LVRT) operations at certain RE plants.
Between 14:02 hrs and 14:06 hrs, low-frequency oscillations of 0.458 Hz were observed within the complex. During this period, three LVRT operations occurred without any associated reduction in generation.
The main disturbance took place at 14:09 hrs following another voltage dip. GRID-INDIA noted that RE plants continued injecting reactive power after the dip, which likely resulted in the tripping of both RE plants and evacuation lines due to High Voltage Ride Through (HVRT) and over-voltage protection mechanisms.
Within 16 seconds, around 17 Extra High Voltage (EHV) transmission lines tripped, including eight 765 kV lines and nine 400 kV lines. The total RE generation loss was estimated at around 9,000 MW.
Frequency response
The sudden loss of generation caused the grid frequency to decline by 0.56 Hz, from 49.953 Hz to 49.398 Hz.
The Under Frequency Load Shedding (UFLS) scheme was automatically triggered at 49.40 Hz under Stage-1 operation, resulting in the shedding of around 6,000 MW of load. However, the relief achieved was below the desired level of around 12,000 MW.
As per the Indian Electricity Grid Code (IEGC), 2023, Pumped Storage Hydro (PSH) plants operating in pumping mode and Energy Storage Systems (ESS) operating in charging mode are required to disconnect automatically before the first stage of UFLS. GRID-INDIA noted that most pumped storage plants did not provide automatic load relief during the disturbance.
The frequency decline was eventually arrested through Primary Frequency Response (PFR), after which the system frequency recovered to 49.598 Hz. Additional support was later provided through Automatic Generation Control (AGC) and tertiary reserve deployment.
Grid stability concerns
GRID-INDIA identified multiple operational and systemic concerns arising from the event.
The organisation stated that the behaviour of RE plants during the disturbance, particularly continuous reactive power injection following the voltage dip, requires detailed examination by the concerned developers.
For further root cause analysis, all RE developers have been asked to submit inverter-level granular data with 1 millisecond resolution or better. The presentation noted that the required data had not yet been submitted at the time of the NCT meeting.
GRID-INDIA also observed that system strength, measured through Short Circuit Ratio (SCR), remains low in the Khavda, Rajasthan and Pachora RE complexes. According to the presentation, low-frequency oscillations linked to low SCR and improper controller tuning are being observed regularly in these RE zones.
The presentation further warned that additional BESS deployment under non-solar hour connectivity arrangements could further weaken SCR levels. GRID-INDIA stated that operational feedback on low SCR conditions has already been shared with the Central Electricity Authority (CEA) and Central Transmission Utility of India Limited (CTUIL).
Measures planned
Following discussions, the NCT agreed on a set of corrective and preventive measures.
GRID-INDIA will carry out a detailed assessment of the UFLS response and follow up with utilities where load relief was inadequate.
Northern Regional Power Committee (NRPC) and Western Regional Power Committee (WRPC) will coordinate with RE developers to obtain root cause analyses, inverter-level data and corrective tuning measures for plant controllers.
CTUIL has been asked to coordinate with Transmission Service Providers (TSPs) to expedite the commissioning of planned Static Synchronous Compensators (STATCOMs) in the Khavda RE complex.
The CEA’s Grid Management (GM) Division will issue an office memorandum mandating Grid Forming (GFM) inverters in all new BESS projects above 50 MW and requiring 25 per cent GFM capacity in all new RE plants. The CEA will also expedite amendments to connectivity standards.
A committee constituted under Member (Power System) [PS] will finalize a uniform methodology for computing SCR. CTUIL has also been directed to plan additional grid-strengthening measures, including Synchronous Condensers (SynCONs), for RE complexes.
