DGen-A — air-cooled turbogenerator, 110–200 MVA

Description

DGen-A is a series of two-pole turbogenerators with fully air cooling, the smallest in the manufacturer's generator range. The generators are intended for drive by steam and gas turbines in combined-cycle plants, small and medium thermal power plants, CHP plants and biofuel stations. Air cooling without a hydrogen system simplifies the auxiliary equipment, lowers the explosion-safety requirements for the machine hall and reduces the scope of maintenance, so such machines are especially convenient for units with frequent starts and manoeuvring modes. According to the manufacturer's catalogue, the DGen-A series is produced at 110–200 MVA in two versions: for 50 Hz networks (3000 rpm) with a rated stator voltage of 10.5–15.75 kV, and for 60 Hz networks (3600 rpm) with 12.5–18 kV. In the manufacturer's range the series occupies the niche of small and medium-power generators; more powerful machines are built with hydrogen (DGen-H) and hydrogen-water (DGen-W) cooling. All turbogenerators of the manufacturer share common design solutions. The stator insulation system is designed for both continuous operation and daily starts and stops, and is confirmed by more than twenty years of operating experience. The stator end windings are secured by a system that withstands the forces of normal and emergency conditions and practically requires no maintenance. The bars in the slots are held by top wedges and wave springs, which eliminates bar vibration and extends insulation life. The core is stacked from low-loss electrical steel and mounted on a support system that isolates its vibration from the frame. The rotor retaining rings are made of non-magnetic 18Mn-18Cr steel, resistant to stress corrosion cracking; the field winding has direct cooling and uniform temperature distribution. Excitation is a static digital system, DS-DEX. The DS-DEX system is built on an open modular architecture and is used with generators driven by turbines of any type. Production takes place at the plant in Changwon (Republic of Korea), where turbines and generators are manufactured, assembled and tested; development is carried out jointly with the R&D centre in Plzeň (Czech Republic). The company also rewinds the stators and rotors of generators in operation.

Technical specifications