Mundra - Mahendragarh

The Mundra-Mahendragarh HVDC project is a power transmission system in India, connecting the western and northern regions of the country. The project is notable for being the first private sector HVDC transmission line in India, developed by Adani Power Limited.

Technical Specifications

The transmission line is a bipolar 500 kV HVDC system with a capacity to transmit 2,500 MW of power. It spans a distance of approximately 986 km, traversing three states: Gujarat (366 km), Rajasthan (567 km), and Haryana (53 km). The line connects the Mundra power station in Gujarat to Mohindergarh in Haryana.

The system has converter stations at Mundra and Mohindergarh, along with two electrode stations. The HVDC link is designed to operate in both bipolar and monopolar modes, with ground return or metallic return options available in monopolar mode.

Performance and Efficiency

One of the key advantages of this HVDC system is its high efficiency. It experiences minimal transmission losses of around 1%, compared to the 5% to 8% average for conventional AC lines. The system is capable of transmitting power in both directions, although the primary flow is from Mundra to Mohindergarh.

Design and Capacity

The converter stations are designed to handle a continuous power of 2,500 MW (±500 kV, 2,500 A) at the DC terminals of the rectifier converter station. They can operate at full rated power continuously at a maximum ambient dry bulb temperature of 50°C without the redundant cooling system. With redundant cooling, the system can handle a 1.1 pu rated power overload for 2 hours.

The HVDC interconnection can operate at reduced DC voltage levels from 500 kV down to 350 kV (70%). At 80% voltage, the maximum DC current is 2,250 A, and at 70% voltage, it's 2,145 A without redundant cooling equipment.

Technology and Equipment

The project utilizes Line Commutated Converters (LCC) based on thyristor valves. It employs modern Light-Triggered Thyristor (LTT) technology, which offers high reliability and requires minimal maintenance due to its compact and economic design.

Performance Guarantees

The system has a guaranteed energy availability of 97% per year for the complete bipole, averaged over a three-year availability guarantee period, considering both forced and scheduled maintenance outages. The maximum specified equivalent outage frequency is 10.

Construction and Commissioning

Siemens AG and its Indian arm Siemens Ltd were awarded the contract to construct this HVDC line in May 2009. The project was completed in two phases, with the first phase commissioned in February 2011 and the second in July 2011. This rapid implementation made it one of the fastest project completions by any power developer in India.