Smaller, high efficiency hydro generators from WEG

WEG has introduced its GH20 Hydro Generator line, a series of small, low and medium voltage generators designed to meet and comply with all aspects of the growing Small Hydro Power Plants (SHPP) market.

The new generators are lighter and more compact in comparison with the previous GH10 design, offering a reduction of up to 70 per cent in volume and 40 per cent in length. This compact envelope enables optimisation within low power hydroelectric power plants, saving up to 30 per cent in total space, and lowering the necessary investment in installation infrastructure.

Aside from the smaller design, the new GH20 Hydro Generators offer more strategic advantages in hydroelectric generating plants, not least the potential to be skid mounted at the factory. This configuration helps to reduce field mounting costs and save time during site installation. Further benefits include vacuum pressure impregnation (VPI) with epoxy resin. The VPI process has for many years shown its efficiency and reliability in rotating electric machines across a variety of applications.

The GH20 Hydro Generators include bearings which have been developed for easy maintenance and high operational reliability. Moreover, the design of the generator’s anti-friction bearings (grease or oil lubricated) means they can withstand both radial and axial loads from the hydraulic turbine and flywheel. As a result, the use of multiple bearings to support turbine and flywheel loads is not required, which in turn reduces the length of the generator turbine assembly.

The line is supplied with protection devices such as thermal sensors, voltage and current measurement devices and speed sensors. The sensors are used to improve and monitor the operation of the generator, bringing greater reliability to its operation. In addition, the generators feature a main terminal box that not only offers six terminals with access to neutral leads but, thanks to the winding process, has been specially designed and specified for the required generation voltage (low or medium). The medium voltage hydro generator coils are manufactured with rectangular copper wire, pre-formed and insulated with mica-based porous tape. Both conducting and semi-conducting strips are used in the winding process, wrapping the coils and ensuring their resistivity.

In terms of specification, technical features of the series include: 300 to 3,900 kVA output; voltage from 380 to 4,160 V; 50 and 60 Hz frequency; and 6 to 16 poles. IP20 and IP21 protection rating versions can be offered.