POWERFORMER

[attachment=16253]

Introduction
Today’s high-voltage generators are constructed in such a way that limits their output voltage to a maximum of 30 kV. Those generators cannot, directly supply the power grid with voltages up to 800 kV, a reason why large power plants nowadays are using power step-up transformers in order to transform their generated voltage to a higher voltage level suitable for the interface with the transmission grid.
The step-up transformer imposes great drawbacks on the power plant as a whole, starting from reduction in efficiency, high maintenance costs, and more space, less availability and not to forget the increased environmental impact of the plant.
During the last century, a number of attempts were made at developing a high-voltage generator that could be connected directly to the power grid, i.e. without going via the step-up transformer. However, although grid voltages can reach 800 kV or more, generators are presently constructed for voltages up to 30 kV only, as stated above.


. Powerformer Concept
Powerformer, although a new machine, it is a 3-phase AC generator with a rotor of conventional design. The difference compared with conventional generator lies in the stator windings. In Powerformer stator winding consists of high-voltage cables instead of today’s windings with a square cross-section. By using high-voltage cables as generator stator winding, it is possible to highly increase the generated voltage. The decisive difference between this design and present-day technology is that Powerformer allows direct connection to the high-voltage grid



Innovative Design
Powerformer has been designed with several unique features that allow it to exceed the 30kV limit, including a winding consisting of power cables and an innovative stator design.

Powerformer windings
The magnetic circuit of Powerformer makes certain demands on the winding. The winding consists of a power cable with solid insulation and two semiconducting layers, one surrounds the conductor and the other outside the insulation, the semiconducting layers serves as an equi-potential surface that forces the electric field to be uniform around the circumference


Non conventional stator design
The design of the slots and teeth in the magnetic circuit plays a decisive role in the optimization of a rotating electrical machine. The slots should enclose the casing of the coil as closely as possible. At the same time, the teeth should be as broad as possible at each radial level. This reduces the losses in the machine and also the need for excitation.