Power from the 3,000 MW coal-fired Rihand thermal power plant in Uttar Pradesh is transmitted over the Rihand-Delhi HVDC bipolar transmission link, which has a rated capacity of 1,500 MW at ±500 kV, and over existing and parallel 400 kV AC lines.
The aim of this HVDC link is to efficiently transmit power from Rihand thermal station to meet the urgent need for power in India's northern region. An HVDC transmission system was chosen for its overall economy, reduced right-of-way requirements, lower transmission losses, better stability on parallel AC lines and better controllability. The Rihand-Delhi HVDC transmission was the first commercial long-distance HVDC link in India.
The two converter stations in Rihand and Dadri, outside Delhi, were supplied jointly by ABB and Bharat Heavy Electricals Limited, a government of India undertaking. The transmission, which was commissioned in 1990, is owned by Power Grid Corporation of India, and includes an 814-km bipolar overhead line.
In order to enhance the reliability of integrated AC/DC bulk power transmission system, special control features were incorporated in the scheme, including power modulation, frequency control, sub-synchronous resonance damping, reactive power control and runback control.