Abstract: A groundwall insulation system for use in dynamoelectric machines carrying voltage above 4 kV, and preferably in the order of 13.8 kV, or higher has two layers of insulation wound onto the conductors of the high voltage winding. The first layer of insulation has a first permittivity that is greater then the permittivity of the second layer of insulation wound onto the first layer of insulation. As a consequence, at the juncture between the first and second layers there is a sharp increase in the electric field profile as seen through the groundwall insulation.

Abstract: There is disclosed a groundwall insulation system for use in dynamoelectric machines carrying voltages above 4 kV and preferably in the order of 13.8 kV, or higher. The groundwall insulation comprises two layers of insulation wound onto the conductors of the high voltage winding. The first layer of insulation has a first permittivity that is greater then the permittivity of the second layer of insulation wound onto the first layer of insulation. As a consequence, at the juncture between the first and second layers there is a sharp increase in the electric field profile as seen through the groundwall insulation. This step increase in the electric field profile results in the electric field adjacent the conductor having a maximum magnitude that is less than that normally experienced by insulation systems in the past.

Abstract: A hydroelectric power generation system (20) generates electrical power for an electrical utilization system (72). A controller (42) obtains a requested output electrical power level from a hydro-turbine unit (70) by using a signal indicative of water head (h.sub.meas) to control speed of an asynchronous rotary converter (50) coupled to the hydro-turbine unit and to control gate position of the hydro-turbine unit. The requested output electrical power level is applied from the hydro-turbine unit via the rotary converter to the electrical utilization system. In one embodiment, the controller (42B) accesses an updatable memory wherein Hydraulic Hill Chart information is stored. In another embodiment, the controller (42C) also includes a real-time automatic governor which uses a signal indicative of ac transmission frequency to the electrical utilization system to control the output electrical power level of the rotary converter.