New Delhi-based WattPower, which makes solar inverters and energy storage solutions, has launched its 506KTL grid-forming string inverter on the opening day of REI Expo 2026 in Greater Noida, India. The 420 kW unit has been designed for utility-scale solar plants on weak grids, and it has therefore been equipped with virtual inertia, power oscillation damping and a black start function.
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WattPower used the opening day of REI Expo 2026 at India Expo Mart in Greater Noida to unveil its 506KTL grid-forming string inverter. The company, which is based in New Delhi, India, makes solar inverters and energy storage solutions, and it has said that it has already supplied more than 24 GW of inverter capacity across the country.
Rated at 420 kW, the 506KTL has been made for utility-scale solar. Its AC side runs at 1,000 V and its DC side at up to 1,600 V. Because WattPower has raised the power density by 40%, the company has said, a developer will need fewer inverters for a plant, and the balance of system should cost less.
Unlike a grid-following unit, a grid-forming inverter such as the 506KTL sets the voltage and frequency at its own terminals. On weak grids, that design is backed by virtual inertia, power oscillation damping and steady operation at a low short-circuit ratio. With its black start function, the inverter can also feed AC power to a site while it is being commissioned, which does away with diesel generators, and after a night-time outage it resets on its own and goes back to supplying reactive power to the grid.
Divya Prakash Choraria, the CEO and Co-founder of WattPower, said that the response on the first day had reflected the sector's growing focus on grid stability alongside generation capacity. Choraria added that grid-forming technology would play a key role in supporting grid stability as more renewable energy is integrated, and that the 506KTL reflected that shift.
At the same stand, WattPower has also displayed a 330 KTL utility solution with a smart array controller and a smart transformer station, a smart PV solution for C&I users and a model of an ultra-fast EV charging station.