Siemens is supplying two gas-insulated high-voltage switchgear (GIS) for the Rogun hydropower plant in Tajikistan, a country bordered by Uzbekistan, Kyrgyzstan, China and Afghanistan. The power plant is part of the Rogun Dam project. At a height of 335 meters, the dam taking shape here will be the highest in the world. The 8DQ1 switchgear, covering a voltage range of up to 550 kilovolts (kV) with 21 circuit breakers, and the 8DN9, covering up to 220 kV with four circuit breakers, will protect the power generation and transmission systems in the hydropower station against short circuits and overloading. The switchgear should be fully installed and ready for operation by 2018.
The Rogun Dam will stand on the river Vakhsh, about 100 kilometers north-east of Tajikistan's capital, Dushanbe. It will be upriver from the Nurek Dam, which is currently the world's highest at 300 meters. A hydropower station with a generating capacity of 3600 megawatts (MW) is planned for the Rogun Dam, with generation provided by six 600 MW turbines. This will enable 13.3 billion kilowatt hours (kWh) of electricity to be generated annually, supplying power to large areas of Central Asia. It will be one of the largest hydropower stations in the world.
The gas-insulated switchgear covering ranges up to 220 kV and 550 kV are supplied with outgoing leads offering particular stability to ensure uninterrupted use even in difficult ambient conditions. The switchgear are fitted with online monitoring devices to enable automatic remote diagnosis and self-monitoring. The 8D series switchgear is metal-enclosed to minimize dielectric and dynamic stresses. Aluminum is used for the metal enclosure to keep the weight of the system to a minimum and ensure optimum corrosion resistance. Sulfur hexafluoride (SF6) is used as the insulating and arc extinguishing gas. The extremely tight enclosure prevents environmental contamination. Static filters in the head spaces provided on the inner side of the assembly openings absorb moisture and decomposition products.
Gas-insulated switchgear systems from Siemens have been developed for an estimated total service life of more than 50 years, and are almost maintenance-free once in operation. The switchgear has corrosion-free enclosures and uses self-lubricating drives, which contributes greatly to their long service life. The main contacts for the circuit-breakers, disconnectors and earthing switches are designed for a long service life and minimum maintenance outlay. The first Siemens GIS panel went into operation in Berlin in 1968 and continues to operate reliably.
Gas-insulated high-voltage switchgear are part of the Siemens Division Energy Management's product portfolio. As a product supplier, system integrator, and solution and service provider, the Division offers power supply companies and industry cost-efficient, reliable, and intelligent solutions for the transmission and distribution of electrical power. The portfolio ranges from products and systems for low-voltage and distribution networks and smart grid and energy automation solutions to high voltage transmission systems. With a presence in more than 100 countries, the Siemens Division earned approximately €11.9 billion in sales and €570 million in profit and employed just fewer than 53,000 employees worldwide last fiscal year, which ended on September 30, 2015.
Source: Siemens AG
Date: Aug 17, 2016