Features

The impulse voltage generators / series G are the main component of impulse voltage test systems, series G (see Data Sheet 3.10), ranging from 1000 kV up to 6000 kV cumulative charging voltage.

They are designed for testing high voltage equipment of power systems with lightning impulses (LI: 1.2/50 µs) and switching impulses (SI 250/2500 µs) according to the IEC standard 60060-1 (IEEE St.4). The maximum charging voltage is 200 kV per stage with a maximum energy of 30 kJ per stage. With 30 stages, maximum output voltages of 5700 kV (+/-LI) and 4500 kV (-SI) can be generated in the no-load case.

The impulse voltage generators can be modified for carrying out a variety of special tests, e.g. on transformers, impulse current testing of surge arresters and even components of wind generators or air planes as well as EMP tests of electrical equipment. The chosen modular system enables a very variable application in industries as well as in laboratories for research and education.

The circuit of the impulse voltage generators is a modified Marx multiplier circuit. The impulse capacitors, arranged in the stages of the generator, are charged with positive and negative DC voltages up to 100 kV each against earth potential and, in order to generate impulses, connected in series by spark gaps. For the adjustment of the front time and time to half value of the approximately double-exponential impulses, the generator stages comprise appropriate front resistors and tail resistors. A short discharge loop guarantees low internal inductances and smooth voltage shape.

All components of the impulse generator are supported by four insulating columns made of glass-fiber reinforced plastic. A stable construction is achieved by rectangular frames in each generator stage. In each third stage there is a folding platform that can be entered for a convenient changing-over of the resistors. These platforms are accessible without risk via an insulating ladder throughout all generator stages. The switching spark gaps of all stages are commonly housed inside a fifth insulating column with a slight air over-pressure to guarantee clean air for a safe triggering. For safe operation, the test generator is equipped with two earthing switches and two motor driven earthing ropes, which additionally short-circuit all impulse capacitors after the generator is switched off.

The four insulating columns are placed on a common sectional steel base which can be designed either as stationary or as a mobile type. The frame carries also the DC generator including the cubicle for the thyristor controller.